Talk:Vitamin D/Archive 5

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The IOM report is fundamentally flawed

See here. We can include the conclusions of this report, but only by qualifying properly what they did, which is not an unbiased review of the entire literature. We can't just say that because it's an IOM report and "IOM= The highest authority in medicine", we should take this report as gospel.

The IOM report even managed to get the not so controversial issues about bone health wrong, leading to lower recommendations of the calcidiol level than the authors cited in the IOM report recommend:

"Michael Amling, a bone expert at the University Medical Center Hamburg-Eppendorf in Germany is one such critic. He says he was thrilled when Rosen e-mailed him in 2009 to enquire about some of his data. "I wanted to support the work of the IOM," says Amling. He assumed its analysis would conclude that most people were vitamin-D deficient, and that this might encourage the German government, which does not fortify food, to reconsider the issue.

The IOM was interested in a study Amling had published, in which he had measured bone quality and blood levels of vitamin D in the bodies of 675 people who had died in good health (for example, in car accidents and suicides)4. Amling concluded that an ideal level for the general population would be 75 nmol/L because everyone above that level had strong bones, and they therefore weren't at a high risk of fractures.

The IOM's mandate was to set the levels that protect most people, but not all. It found that Amling's data supported a 50 nmol/L threshold (which had been suggested elsewhere in the literature) because at that level, only 1% of people in the study had weak bones. But Amling says that the IOM made a mathematical mistake: it should have looked at the risk of weak bones in people at or above a certain level, not in the whole population (see 'Denominator dispute'). Instead of dividing the 7 people with weak bones and levels above 50 nmol/L by all 675 people in the study, he says it should have divided 7 by the 82 individuals with levels above 50 nmol/L. Charles McCulloch, a biostatistician at the University of California, San Francisco, who has no vested interest in vitamin-D thresholds, agrees: the panel should have found that 8.5% of the population above 50 nmol/L had weak bones, and therefore according to its goal of allowing no more than 2.5% of the population to be at risk, Amling's data would support a higher level. "I'm very shocked they made such a basic mathematical mistake," Amling says.

Another researcher whose work received a fair share of the IOM's attention is Heike Bischoff-Ferrari, director of the centre for ageing and mobility at the University of Zurich in Switzerland. She published a meta-analysis in 2009 that pooled eight clinical trials testing the ability of vitamin-D supplements to reduce falling in elderly people5. In her analysis, participants who took daily doses of 700–1,000 IU fell less often than those taking a placebo. Doses below 700 IU made no difference.

When the IOM panel came to analyse Bischoff-Ferrari's data, it decided to include different studies. It removed a study6 showing a benefit from doses higher than 800 IU because the study had focused on groups of about 20 people, which the panel considered too small. And it added a trial7 that Bischoff-Ferrari had excluded because it hadn't been double-blinded. Once the IOM swapped trials in Bischoff-Ferrari's meta-analysis, the evidence showed no benefit from supplementation. Needless to say, Bischoff-Ferrari and others disagree with the IOM's decision.

With no universal criteria to identify which studies ought to be included in meta-analyses, it's hard to say which team selected the most appropriate ones. What is clear, however, is that a lack of high-quality primary research makes these decisions difficult and prone to bias.

Another criticism levelled at the report has to do with the IOM's warning that too much vitamin D could cause harm. In the only clinical trial claiming risk, elderly women treated with a single 500,000-IU dose of vitamin D annually fell and fractured their bones more often than those in the placebo group8. Many researchers find the study ridiculous. "No one absorbs 500,000 IU a day from the Sun, so why would you give that as a supplemental dose?" says Edward Giovannucci, a nutritional epidemiologist at the Harvard School of Public Health in Boston, Massachusetts."

So, even on the non-controversial issues like bone health, the report doesn't reflect the scientific opnion of the experts well enough to be given so much weight in this article.

About the other health effects of vitamin D, the IOM report is competely off the mark. The IOM report itself does say that they use a double standard for such evidendce. They have a low threshold for admitting evidence suggesting that there are adverse health effects, while they use a very high threshold for evidence for beneficial health effects. This was criticed by Holick and others. Wikipedia must clearly state this difference in threshold level when it cites IOM report.

Another issue is that health benefits does not necessarily equate to a clear signal in disease prevention. Such a signal can be too difficult to see in short term double blind trials as Dr. Vieth points out. Also, you have to consider that health benefits can be accompanied with a slight increase in the risk of developing certain diseases, so the two things are not necesarily the same at all. E.g. we know that calorie restriction to about 1500 Kcal per day or less is very likely able to lower the risk of getting diseases like heart disease and cancer. But then you would probably need to sleep 12 hours per day and the 12 hours you are awake, you cannot be very active. Count Iblis (talk) 23:25, 28 October 2011 (UTC)

Thanks for that, Iblis. -- cheers, Michael C. Price ^talk 05:36, 29 October 2011 (UTC)

Iblis, In my edit I included a small section on 'dissenting opinions and gave it the best ref I could find and a week or so ago left in a mention by Greensburger that some members of the 97 IoM committe on vitamin D agreed with this school of thought. I'm not the one claiming that high dose vitamin D advocates should be given NO voice in the article. DocJames is the one saying that unless it is supposted by a REF to a REVIEW it can not go on the page. ("Please provide one review that concludes their are health benefits other than bone health. Thanks Doc James ") He and you are in agreement that the IoM are not the supreme authority on vitamin D. Calorie or carbohydrate restriction is an interesting subject (check out Michael Ristows work), but let's stick to discussion of the matter at hand please . The weight I gave to the major IoM report on vitamin D went along with mentioning that some experts disagree with them. Overagainst (talk) 13:04, 29 October 2011 (UTC)

Iblis and Michael C. Price, To be clear I am happy for there to be a section which gives the high dose advocates among experts a voice. I just didn't think that it could be presented as equal in weight to the IoM. DocJames has taken that section (the dissenting opinions section out completely. He says the ref ('Why the IOM recommendations for vitamin D are deficient')is not a proper ref It is now going to stay out unless someone else (Not me I can't revert it again) reverts back to the version which included it. If you choose to revert back to that version we could collaboratively edit it to somewhat expand the section giving the Hollick viewpoint. There needs to be more refs for in a somewhat expanded version of the section. the original one Why the IOM recommendations for vitamin D are deficient Update of vitamin d. Overagainst (talk) 14:22, 29 October 2011 (UTC)

Okay, I concur. DocJames has systematically gutted the article of information. I'm reverting back to some semblance of sanity so that we can work forward with this.-- cheers, Michael C. Price ^talk 14:53, 29 October 2011 (UTC)

We use review articles per consensus. I am happy to see people imporve this further but returning all the primary research is not cool. The sections on health effects was also a mix of pathophysiology (these are not health effects) Doc James (talk · contribs · email) 13:58, 30 October 2011 (UTC)

Unless there is a Wikipedia guideline forbidding the use of primary studies I don't think we can say that none of them belong in the article at all. Why don't you make some detailed and specific proposals for the text and referenced studies in the health effects section which could be done without or reffed by a review instead of a primary study . Bone-health is uncontroversial and has many reviews which could be used as refs; primary studies could be dispensed with there. The mortality section has a review ref (IoM) for "The data suggest a U-shaped shaped risk curve between serum 25OHD level and all-cause mortality; increases in risk with high levels appear at a lower threshold for the black population.[176]" as that is from a review I propose deleting the following; "Calcifediol (25-hydroxy-vitamin D) is implicated in the etiology of atherosclerosis, especially in non-Caucasians.[106][108][167][168] Freedman et al. (2010) found that serum vitamin D correlates with calcified atheroscleratic plaque (CP) in African Americans, but not in Euro-Americans, Higher levels of 25-hydroxyvitamin D seem to be positively associated with aorta and carotid CP in African Americans but not with coronary CP. These results contradict what is observed in individuals of European descent.[168] ". Overagainst (talk) 17:28, 30 October 2011 (UTC)

Sure feel free to add it back in. Doc James (talk · contribs · email) 10:24, 31 October 2011 (UTC)

We have "Ideal sources for biomedical material include general or systematic reviews in reliable, third-party, published sources, such as reputable medical journals, widely recognised standard textbooks written by experts in a field, or medical guidelines and position statements from nationally or internationally recognised expert bodies." Thus the IoM and review articles. If these did not exist than yes we could consider using primary research sparingly. But the guideline is fairly clear that primary refs should rarely be used and only with great caution. None of the ones I removed is in the should be used group (think Women's Health Initiative for primary sources that may be justified).--Doc James (talk · contribs · email) 10:54, 31 October 2011 (UTC)

So unless we can agree that this is the direction we need to move this article (basing it on review articles and major governmental position papers like the IoM). 1) we will have trouble working together 2) we will have trouble getting it to GA.--Doc James (talk · contribs · email) 10:58, 31 October 2011 (UTC)

Dissenting/Other opinions on vitamin D

Some refs Vitamin D supplementation for prevention of mortality in adults'Vitamin D in the form of vitamin D3 seems to decrease mortality in predominantly elderly women who are mainly in institutions and dependent care'.

Vitamin D, obesity, and obesity-related chronic disease among ethnic minorities: A systematic review. Overagainst (talk) 16:37, 29 October 2011 (UTC)

Agree and have added it.--Doc James (talk · contribs · email) 10:25, 31 October 2011 (UTC)

Primary research

Before we had stuff like this

A study done in Norway consisted of 246 patients with hip fractures who were studied for risk factors.[116] Results showed that a vitamin D intake lower than 100 IU/day was associated with an increased risk for hip fracture.[116] Vitamin D supplements may also increase bone mineral density in other parts of the skeleton.[116] A study showed that a supplement of 800 IU per day of vitamin D increased the bone mineral density of the lumbar spine in postmenopausal women in comparison with the control group.[116]

This sort of text is not supported by policy. A 246 patient primary research study is not notable. And community consensus is in support of the fact that this sort of content should be removed and replaced with high quality references.Doc James (talk · contribs · email) 11:09, 31 October 2011 (UTC)

Agree with Doc James, we really, really need to remove primary studies from this article, as the extensive use of them goes against our policies, guidelines, and creates WP:UNDUE weight by cherry picking which of the thousands of primary studies on Vitamin D we include and which we don't. Yobol (talk) 23:54, 1 November 2011 (UTC)

The distinction between primary and secondary sources is fuzzy and does not guarantee absence of bias. A retrospective study could be viewed as a secondary source because it reviews and reanalyzes experimental data and findings from several prior primary studies. But if those prior studies were cherry picked and flawed or if some of the prior studies were misrepresented in the retrospective study, the retrospective study may be far less reliable than primary studies that provide evidence that the prior studies were flawed or misrepresented. Review articles may disregard those dissenting opinions and not mention the flaws, simply because the dissenting opinions are in the minority, not because the alleged flaws were not flaws. Primary studies that reveal those flaws may not be conclusive, but should be included in Wiki articles simply to illustrate dissenting opinions and to illustrate cherry picking in the secondary sources. Greensburger (talk) 01:38, 2 November 2011 (UTC)

Retrospective studies do unique analyses on data and are, by definition, primary. If reviews do not mention the flaws, then they are not notable. We do not include primary studies to debunk secondary studies, nor do we include primary studies because of their viewpoints against WP:DUE weight in the literature. If there is significant dissent, then it will be noted in the secondary reviews. Yobol (talk) 03:28, 2 November 2011 (UTC)

Suppose there are ten primary studies in reputable journals that state that XYZ is a fact, and a flawed secondary study claims that XYZ is not a fact, but no review has been found that reviews those ten primary studies and concludes that XYZ is an established fact. You are saying that the flawed study must be reported in Wikipedia with no mention of the ten reliable studies that prove the opposite. Of course we can hope that at least one reliable review can be cited that debunks the flawed study. My point is that until such a debunking review can be found, balanced coverage requires at least one or two of the ten primary studies should be cited as a temporary place holder until a reliable debunking review is found. Greensburger (talk) 05:10, 2 November 2011 (UTC)

But this is not the case here. Yes if all we had where 20 year old review articles we would have a problem. But there are dozens of recent review articles on this topic and thus no need to use primary research. The have done analysis of how well reviews and primary research stands the test of time and while the majority of primary research is contradicted within 10 years the miniority of review articles are. We of course give preference to systematic reviews for specific questions.Doc James (talk · contribs · email) 09:44, 2 November 2011 (UTC)

Proposed edit

I'm reading this article for the first time in a long time, and was wondering whether editors here would support a change from

The assumption that vitamin D levels in the population follow a latitude gradient is especially questionable in view of surveys which have shown that UVB penetrating to the earth's surface over 24 hours during the summer months in northern Canada equals or exceeds UVB penetration at the equator. Accordingly, there is sufficient opportunity during the spring, summer, and fall months at high latitude for humans to form and store vitamin D₃^[1]

to

The relationship between latitude and UVB penetration is complicated by factors such as atmosphere height (50% higher at the equator), cloud cover (denser at the equator) and ozone layer density, and latitude does not consistently predict the average serum 25OHD level of a population. UVB penetrating to the earth's surface over 24 hours during the summer months in northern Canada (where summer days are longer) equals or exceeds UVB penetration at the equator, allowing sufficient opportunity during the spring, summer, and fall at high latitude for humans and their food animals to form and store vitamin D₃. This, combined with recent computer modeling may call into question the assumption that vitamin D levels in the population follow a latitude gradient.^[1]

Agreed, As DocJames is OK with it I made the change.Overagainst (talk) 12:47, 2 November 2011 (UTC)

Rationale

This replaces "especially questionable" with "may call into question", the language of the source; adds the confounding factors, atmosphere height, cloud cover and ozone layer; adds the contribution of food animals to dietary D; and clarifies that the "question" in the source derives from both the computer modeling and the geophysical surveys. --Anthonyhcole (talk) 09:06, 2 November 2011 (UTC)

No issue with this proposed change. Being from the North myself we go 5 month wearing lots of clothing. We never go outside in the sun without at least three layers. I have seen minus 48 degree C. I wear a ski mask to cover my eyes and face mask, a down jacket, ski pants and full gloves. Any exposed skin will get frozen quickly. Thus the amount of UVB reaching the ground is not that significant.Doc James (talk · contribs · email) 09:29, 2 November 2011 (UTC)

I'm walking around in shorts and crocs at the moment. Australia is Canada with good weather. :) --Anthonyhcole (talk) 10:06, 2 November 2011 (UTC)

You are wise to protect your eyes in Canada DocJames, MedicineNet.com ('We bring Doctors' knowledge to you') states "Snowblindness: A burn of the cornea (the clear front surface of the eye) by ultraviolet B rays (UVB). Also called radiation keratitis or photokeratitis" UVB photons bounce off the clouds, ground and especially the snow like ping pong balls. In Oz you could sit in the shade and still get a lot of UVB, enough - as Dr. Kimlin has shown - to activate vitamin D production in the skin. Here is a nice study by Kimlin et al Location and Vitamin D synthesis:Is the hypothesis validated by geophysical data? Overagainst (talk) 12:42, 2 November 2011 (UTC)

It is incredibly cold in Canada for sure but if you will look at this overlay of European cities onto North America you may be surprised (I was).Overagainst (talk) 13:08, 2 November 2011 (UTC)

Layout

Before we had a section on "health effects" and one on "Vitamin D and health outcomes" I have merged them into one called "Health effects". Some of the content did not related to "health effects" such as recommended intact and this was split into its own section. We could have a section on "Mechanism of action" to discuss how vitamin D effects human biochemistry. Changes in biochemical values are not however "health effects" this referring to hard endpoints rather than markers.--Doc James (talk · contribs · email) 11:06, 31 October 2011 (UTC)

The problem is Doc that you have not tried collaborative editing, you made massive changes to text and layout without discussing them first and now you want everyone else to accept that they are a fait accompli. I want to discuss changes. Obviously you have good points about the need to clean up the article and remove some primary studies and have things in the relevant section, maybe you have a point about the layout too. But I'm not convinced this article should have the same layout as the caffine one as yet. When you revert the layout you are in effect reverting to a completely new article which you created without any discussion. Can we please start with the text and refs, get that sorted out and them discuss the layout. I think your version of the article is not good at all; the refs for the health effects section are inferior to the IoM, I don't understand why they are there and the text seriously misrepresents the balence of scientific opinion as to the effect of vitamin D supplements.Overagainst (talk) 19:16, 31 October 2011 (UTC)

And I am afraid that the text is plain wrong in places - "Vitamin D appears to have a protective effect against multiple sclerosis.[30] While the initial hypothesis was based on that fact that MS occurred at high rates in the region of the world with long periods with little sunlight further supportive evidence is now available.[30]" reffed to 'Ascherio, A; Munger, KL, Simon, KC (2010 Jun). "Vitamin D and multiple sclerosis.". Lancet neurology 9 (6): 599-612. PMID 20494325.'

Layout and sections are one thing but assertions of that kind are another. One cherry picked review article is not sufficient for making the assertion that vitamin D appears to have a protective effect on MS . Dietary Reference Intakes for Calcium and Vitamin D (2011)Page 173 "Systematic reviews and meta-analyses The AHRQ-Tufts systematic review found no RCTs for immune function clinical outcomes and no evidence for MS related to vitamin D." I have already pointed this out why do you keep including that false assertion about MS? We need to agree about the text then work on the layout.Overagainst (talk) 19:40, 31 October 2011 (UTC)

Something else about the incorrect assertions which were inserted in a prominent position in the article during the layout change. The following was in the above mentioned section about MS but the point about latitude could appply to almost any health outcome: "While the initial hypothesis was based on that fact that MS occurred at high rates in the region of the world with long periods with little sunlight" it said. That would be north Canada right? Dietary Reference Intakes for Calcium and Vitamin D (2011),Page 105 "More recent data may call into question current assumptions about the effect of latitude. In fact, Kimlin et al. (2007), using computer modeling, concluded that it may no longer be correct to assume that vitamin D levels in populations follow latitude gradients. Indeed, the relationship between UVB penetration and latitude is complex, as a result of differences in, for example, the height of the atmosphere (50 percent less at the poles), cloud cover (more intense at the equator than at the poles), and ozone cover. The duration of sunlight in summer versus winter is another factor contributing to the complexity of the relationship. Geophysical surveys have shown that UVB penetration over 24 hours, during the summer months at Canadian north latitudes when there are many hours of sunlight, equals or exceeds UVB penetration at the equator (Lubin et al., 1998). Consequently, there is ample opportunity during the spring, summer, and fall months in the far north for humans (as well as animals that serve as food sources) to form vitamin D3 and store it in liver and fat. These factors may explain why latitude alone does not consistently predict the average serum 25OHD level of a population." Overagainst (talk) 11:22, 1 November 2011 (UTC)

O', stop asking loaded questions, along the lines of "why do you make false statements". There are other studies (inluding an intervention trial) which report ameliative effect of vitamin D on MS symptoms.-- cheers, Michael C. Price ^talk 05:08, 2 November 2011 (UTC)

The Lancet review from 2010 states "Overall, the results of these studies support a protective effect of vitamin D" I reworded it as "Vitamin D appears to have a protective effect against multiple sclerosis." What is wrong with this? I am happy to discuss review articles but continuely attempted to return primary research is against many policies as stated by Yobol. If you find another recent review that contradicts this yes feel free to add it but do not quote primary research as we do not use primary research to refute review articles and this is very clear.Doc James (talk · contribs · email) 09:25, 2 November 2011 (UTC)

Let us be clear, In arguing that you should not be trying to insert the statement "Vitamin D appears to have a protective effect against multiple sclerosis" into the article I cited the IoM report. You can not call that primary research. You have cited a review article from a prestigous journal but it's not good enough. Against the conclusions of an exhaustive review of studies on potential health outcomes (including MS) by the Institute of Medicine which "found that the evidence supported a role for these nutrients in bone health but not in other health conditions" the Lancet article, review or not, is a wholly inadequate reference.Overagainst (talk) 13:26, 2 November 2011 (UTC)

I have no problem with the IoM opinion being here aswell. Both opinions should be present.Doc James (talk · contribs · email) 17:00, 2 November 2011 (UTC)

I have to agree that we need to place all reviews in the article; while significant weight needs to be given to the IOM report, we can't act like it is the only opinion available. Yobol (talk) 17:19, 2 November 2011 (UTC)

Yobol said "I have to agree that we need to place all reviews in the article" huh? I suppose you meant to say we should have only reviews in the article, Yobol. Reviews are preferred over the primary studies because they are more authoritative, the IoM is more authoritative still, because it is a tertiary source. You can't call the IoM report an 'opinion'. There is already some balancing of the IoM report in the article.Overagainst (talk) 22:13, 2 November 2011 (UTC)

No, I meant that we need to use all MEDRS compliant sources, including those that dissent with the IOM, with due weight. Yobol (talk) 22:14, 2 November 2011 (UTC)

A collage of different opinions all of equal standing, sounds confusing.Overagainst (talk) 22:17, 2 November 2011 (UTC)

We need to represent all significant viewpoints, including when they contradict. Yobol (talk) 22:18, 2 November 2011 (UTC)

Yes the use of review articles is accepted practice that one does not need to obtain talk page consensus to add.Doc James (talk · contribs · email) 10:17, 3 November 2011 (UTC)

Yobol,The use of review articles is most certainly not mandated in order to include 'all significant viewpoints'. Review article are prefered to primary studies because their conclusions are broadly based and less likely to represent a particlar viewpoint. Yobol you really must stop referring to the IoM report as if it is one persons opinion or viewpoint the article gives a link (ref 36) to biographical sketches of the 14 committee members. Here is what one, Clifford Rosen, said about the criticism of the report "This is the beginning of a whole new phase," he says. "In the old days of medicine we believed experts, and now we say, show us the data".

We are mandated, by policy to include all significant viewpoints, which would include any reviews published in high quality journals that meet MEDRS. The IOM report deserves significant weight, but we cannot treat it as the final authority when others disagree in MEDRS compliant papers, especially systematic reviews, even if they differ with the IOM conclusions. Yobol (talk) 15:24, 3 November 2011 (UTC)

DocJames, maybe if you just tried giving the number of the ref you object to we could look at it and might agree with you. But you are making major changes each time and it is difficult to see what you are doing . Please leave the layout alone for now and take it one step at a time, preferably giving the ref no.s here beforehand. It might be a good idea to start with the refs that you consider most objectionablly sourced (ie ref to a blog post or internet site). Overagainst (talk) 12:44, 3 November 2011 (UTC)

Yobol, please put new text below old text and do not insert your response into my comments, I don't have Alzheimer's and can follow things. Now about your link (the word 'policy')- "Neutrality requires that each article or other page in the mainspace fairly represents all significant viewpoints that have been published by reliable sources, in proportion to the prominence of each viewpoint". Right, I am all in favour of this being applied to the article, in fact it already is; the Institute of Medicine report stands above all other authorities. They are the go-to people for health information (not on this isssue but on any issue which they issue a report on NYT articles on the Institute of Medicine), The US and Canadian governments asked them to prepare this report, I think that speaks for itself and is proof of the amount of weight their findings carry. They issued a major report and everyone in the field must take account of it

NYT"The 14-member expert committee was convened by the Institute of Medicine, an independent nonprofit scientific body, at the request of the United States and Canadian governments. It was asked to examine the available data — nearly 1,000 publications — to determine how much vitamin D and calcium people were getting, how much was needed for optimal health and how much was too much." I'm not sure what you mean by 'final authority' Yobol, I do not object to it being mentioned that some experts (like Dr. Michael Holick) disagree whith the Institute of Medicine about vitamin D. There is already a section in the article to this effect maybe we could mention Hollick by name. From your link to policy "If a viewpoint is in the majority, then it should be easy to substantiate it with reference to commonly accepted reference texts;

If a viewpoint is held by a significant minority, then it should be easy to name prominent adherents". I'm fine with that in fact that is what I have tried to do. But the Institute of Medicine report is the accepted reference text or tertiary source on vitamin D, it's not just one of many voices in a debate nor is it an opinion or viewpoint. On no pretext whatsoever can the Institute of Medicine report be treated as if it is just another 'MEDRS compliant paper'. No one knew what was what looking at 'MEDRS compliant papers' that is why the US and Canadian governments asked the Institute of Medicine to prepare its report on vitamin D. Your way will result in an ever expanding number of contradictary reviews being added to the article. It will go on and on and there will be chaos. From your link "Keep in mind that, in determining proper weight, we consider a viewpoint's prevalence in reliable sources, not its prevalence among Wikipedia editors or the general public.". Overagainst (talk) 16:56, 3 November 2011 (UTC)

I added to the 'Criticism of the IOM report' section in the article, which already said that a wide ranging 2011 review showed postive effects of supplementation on mortality (in elderly women resident in institutions) that the review was from the "respected Cochrane Collaboration". That is giving it due weight I think.Overagainst (talk) 17:22, 3 November 2011 (UTC)

Do the IOM report conclusions fairly summarize a majority of its members?

Due and undue weight "If a viewpoint is held by a significant minority, then it should be easy to name prominent adherents;". OK that is fair enough, I added to the 'Dissenting opinions on vitamin D levels' subsection that proponents of higher recomendations for vitamin D levels include "Robert P Heaney and Michael F Holick who were members of the panel which drafted the 1997 report on vitamin D from the Institute of Medicine".Overagainst (talk) 17:37, 3 November 2011 (UTC)

Also Grant, Vieth, Hollis, Wagner, Garland and many other experts. I'm actually wondering if the number of experts who think that the IOM was right to say such things as "600 IU/day is enough", "No evidence that vitamin D is involved in anything else but bone health" isn't smaller than the number of experts who disagree on such very important issues. Count Iblis (talk) 17:47, 3 November 2011 (UTC)

An issue here is that the IOM report is meant to be in some respects an authorative judgement for the field of medicine. The field of medicine is different from other scientific fields like e.g. astrophysics, because there are patients whose lives depend on the guidelines given to doctors. But this demands a very conservative approach. The way the IOM reviewed papers has more of a character of how a court would arive at a verdict than performing an unbiased review of the scientific literature. The IOM report itself was not peer reviewed. The IOM is deliberately biased toward not accepting new positive health effects and biased toward accepting adverse health effects. The former needs to meet a much higher burden of proof than the latter.

This is exactly what they had to do, but we do then need to take into account the fact that the IOM did indeed go about reviewing the literature in this way. So, there isn't then necessarily a contradiction between the IOM not coming out supporting certain claims and other review articles that do support that same claim. Count Iblis (talk) 18:38, 3 November 2011 (UTC)

"The IOM report itself was not peer reviewed." It was reviewed.

NYT"“The number of vitamin D tests has exploded,” said Dennis Black, a reviewer of the report who is a professor of epidemiology and biostatistics at the University of California, San Francisco. At the same time, vitamin D sales have soared, growing faster than those of any supplement, according to The Nutrition Business Journal. Sales rose 82 percent from 2008 to 2009, reaching $430 million. “Everyone was hoping vitamin D would be kind of a panacea,” Dr. Black said. The report, he added, might quell the craze. “I think this will have an impact on a lot of primary care providers,” he said."[...]Evidence also suggests that high levels of vitamin D can increase the risks for fractures and the overall death rate and can raise the risk for other diseases. While those studies are not conclusive, any risk looms large when there is no demonstrable benefit. Those hints of risk are “challenging the concept that ‘more is better,’ ” the committee wrote. That is what surprised Dr. Black. “We thought that probably higher is better,” he said. He has changed his mind, and expects others will too: “I think this report will make people more cautious.”" Overagainst (talk) 21:24, 3 November 2011 (UTC)

Using primary research to refute review articles

I am not willing to compromise on people using primary research articles in an attempt to refute review articles. The Huffington post is also not a reliable source. And two is not many.Doc James (talk · contribs · email) 10:50, 3 November 2011 (UTC)

Still no comment related to this policy. Thus restoring reviews.--Doc James (talk · contribs · email) 00:44, 5 November 2011 (UTC)

Doc James, WT:MEDRS is where to comment on policy. This page is for how to improve the article. The trouble is not policy but the lack of clarity about how you're interpreting the policy in specific instances. In short, despite repeated requests you're not being specific about proposed changes. Everything is being bundled into a huge take it or leave it edit which is justfied as policy. There is no consensus for the massive edit of content and layout that you keep making (and adding to ), it makes it very difficult to see what the changes are for one thing. Please can we go one step at a time. Quote one specific part of the text you object to, a managable para or section, explain your reasons and them give the text and refs you want to replace it with. Then there'll be a timely discussion. Is it too much to ask for you to go one step at a time instead of altering the entire article and saying in an edit summary you're 'restoring reviews' (in fairness you are doing far more than that).

Another issue is that an encyclopedic article will mention the alternative theoretical formulation which Hollick and Heaney are advocates for. Your interpretation of policy will prevent that as far as I can see. Overagainst (talk) 10:14, 5 November 2011 (UTC)

I have replaced primary research with review articles. You and Price continue to remove all of the review articles. There for example was not a summary of the health effects of supplementation in the lead. I added it supported by 5 recent review articles in main stream scientific publications from the last 3 years..

The evidence for the health effects of vitamin D supplementation in the general population is inconsistent. The best evidence of benefit is for bone health and a decrease in mortality in elderly women.

Doc James (talk · contribs · email) 12:30, 5 November 2011 (UTC)

I provided a clear example of some of the poor quality previous text here [1]. There has been no justification for continually replacing it.Doc James (talk · contribs · email) 12:46, 5 November 2011 (UTC)

The justification is (1)the changes are embedded in a massive edit which is in effect a completely new article and that the reasonable changes are bundled into one huge edit along with questionable changes. You choose not to go to talk and discuss changes before making them (as I did when I made far less drastic edits) and people reverted the changes pending discussion. If you had appproached this in the way Anthonyhcole did (ie going to Talk and discussing your rationale for every big proposed edit you would not have had the problem. (2) I think some of what you say is plain wrong according to the best source on the subject, namely the IoM. For example The IoM found Vitamin D does not protect against MS so you can't say it does.

I am not here to provide the "truth". Just to reflect the best avaliable references. Do you wish to start this discussion by address one health effect at a time? We can start with MS if you like.Doc James (talk · contribs · email) 13:20, 5 November 2011 (UTC)

OK, lets start with MS.Overagainst (talk)

Vitamin D is involved in a lot of processes that have nothing to do with bone health

See here

"Activated vitamin D (calcitriol) is a pluripotent pleiotropic secosteroid hormone. As a steroid hormone, which regulates more than 1000 vitamin D-responsive human genes, calcitriol may influence athletic performance. Recent research indicates that intracellular calcitriol levels in numerous human tissues, including nerve and muscle tissue, are increased when inputs of its substrate, the prehormone vitamin D, are increased."

It may be involved in cancer prevention

Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act

These are all review articles reporting health effects other than bone health (and there are many more such articles). Count Iblis (talk) 18:05, 3 November 2011 (UTC)

Count Iblis, There is a section which gives the advocates for higher vitamin D levels a voice in the article and there is already a high quality review which is positive about supplementation used there. Maybe you should list the very best reviews you can find and then we'll see what the reactions are on Talk. By the way, I am not the one insisting that only review sources can be used in the article. Overagainst (talk) 20:32, 3 November 2011 (UTC)

Stop thinking in terms of advocates of levels, that reminds me of the long history of sarcoidosis vandalism where advocates of a certain theory disfigured that article repeatedly. WP should summarize all facets of available information. Richiez (talk) 21:56, 3 November 2011 (UTC)

Please take a look at this Richiez " The statement that skeletal health can be ensured at serum 25(OH)D levels of 20 ng/mL is simply incorrect. [...] The privilege instead must be given to the intake that prevailed during the evolution of human physiology, the intake to which, presumably, that physiology is fine-tuned. So far as can be judged from numerous studies documenting the magnitude of the effect of sun exposure,(12,13) the primitive intake would have been at least 4000 IU/day and probably two to three times that level, with corresponding serum 25(OH)D levels ranging from 40 to 80 ng/mL". Source; Heaney and Hollick, Why the IOM Recommendations for Vitamin D Are Deficient – Mar 2011. I don't see how Heaney and Hollick were misrepresented in the fragment of discussion you picked up on. The article certainly makes clear that they believe disease can be prevented by higher vitamin D levels. If anything the text tones down their views somewhat. I have never been to the sarcoidosis article.Overagainst (talk) 13:23, 4 November 2011 (UTC)

Richiez, said "WP should summarize all facets of available information". I'm confused as that would mandate what you seem to be objecting to in relation to the the sarcoidosis page, namely fringe theories being added to articles. Obviously Heaney and Hollick are not fringe scientists; they are prominent adherents propounding an alternative theoretical formulation from within the scientific community and are named as such. They and their school of thought are given a section in the article. No one can just exclude information on WP. Due and undue weight. Overagainst (talk) 16:12, 4 November 2011 (UTC)

Part of this is mechanism of action which is separate from health effects.Doc James (talk · contribs · email) 12:32, 5 November 2011 (UTC)

But yes agree we need to discuss Vitamin D by health condition not but "advocates"/"skeptics" or what have you which makes no sense at all.

I have summarized the literature here as

===Cancer===

Low vitamin D levels are associated with some cancers. When supplementation is used to treat people with prostate cancer, however, there does not appear to be a benefit. Results for a protective or harmful effect of vitamin D supplementation in other types of cancer are inconclusive.

Doc James (talk · contribs · email) 12:53, 5 November 2011 (UTC)

Health effects

Have rewritten the health effects sections using review articles as follows:

==Health effects==

The effects of vitamin D on health is uncertain. An Institute of Medicine report states: "Outcomes related to cancer/neoplasms, cardiovascular disease and hypertension,diabetes and metabolic syndrome, falls and physical performance, immune functioning and autoimmune disorders, infections, neuropsychological functioning, and preeclampsia could not be linked reliably with calcium or vitamin D intake and were often conflicting."

Mortality

Low blood levels of vitamin D are associated with increased mortality. Supplemental with vitamin D(3) appears to decrease all cause mortality with the best evidence of a benefit in elderly women. Vitamin D(2), alfacalcidol, and calcitriol do not appear to be effective.

Overall, excess or deficiency in the calciferol system appear to cause abnormal functioning and premature aging. The data suggest a U-shaped shaped risk curve between serum 25OHD level and all-cause mortality; increases in risk with high levels appear at a lower threshold for the black population.

Bone health

Low serum vitamin D levels are associated with rickets, falls, and low bone mineral density. Supplementation with vitamin D and calcium improves bone mineral density slightly, as well as decreases the risk falls and fractures in certain groups of people. The quality of the evidence is, however, poor.

Cardiovascular disease

Evidence for health effects from vitamin D supplementation for cardiovascular health is poor. Moderate to high doses may reduce cardiovascular disease risk but are of questionable clinical significance.

Cancer

Low vitamin D levels are associated with some cancers. When supplementation is used to treat people with prostate cancer, however, there does not appear to be a benefit. Results for a protective or harmful effect of vitamin D supplementation in other types of cancer are inconclusive.

Other

Vitamin D appears to have a protective effect against multiple sclerosis. While the initial hypothesis was based on that fact that MS occurred at high rates in the region of the world with long periods with little sunlight further supportive evidence is now available. The relationship between latitude and UVB penetration is however complicated by factors such as atmosphere height (50% higher at the equator), cloud cover (denser at the equator) and ozone layer density, and latitude does not consistently predict the average serum vitamin D level of a population. UVB penetrating to the earth's surface over 24 hours during the summer months in northern Canada (where summer days are longer) equals or exceeds UVB penetration at the equator, allowing sufficient opportunity during the spring, summer, and fall at high latitude to form and store vitamin D₃. This, combined with recent computer modeling may call into question the assumption that vitamin D levels in the population follow a latitude gradient.^[1] Whether vitamin D supplements during pregnancy can lessen the likelihood of the child developing MS later in life is not known.

Vitamin D appears to have effects on immune function. It has been postulated to play a role in influenza with lack of vitamin D synthesis during the winter as one explanation for high rates of influenza infection during the winter. For viral infections, other implicated factors include low relative humidities produced by indoor heating and cold temperatures that favor virus spread.

--Doc James (talk · contribs · email) 12:32, 5 November 2011 (UTC)

MS

Vitamin D appears to have a protective effect against multiple sclerosis. While the initial hypothesis was based on that fact that MS occurred at high rates in the region of the world with long periods with little sunlight further supportive evidence is now available.

Do people feel this is an accurate summary of the source in question? Are there other sources that deal specifically with MS that disagree or could be used to expand upon this?Doc James (talk · contribs · email) 13:27, 5 November 2011 (UTC)

Accuracy is not the issue. I don't think your ref is good enough to make that statement. Citing a review article from a prestigous journal like the Lancet would be sufficient if there was no higher authority but it's not good enough against the conclusions of an exhaustive review of studies on potential health outcomes (including MS) by the Institute of Medicine which "found that the evidence supported a role for these nutrients in bone health but not in other health conditions" The Lancet article, review or not, is a wholly inadequate reference. I don't understand how you can say (as you do above) "I have no problem with the IoM opinion being here as well. Both opinions should be present.Doc". Isn't that exactly what you are complaining about . You keep saying against Michael C. Price that primary studies don't count against secondary sources. Now, it seems, you are happy arguing that secondary sources do count against tertiary sources when it suits you. Can't have it both ways. If primary is inferior to secondary, secondary is inferior to tertiary. Dietary Reference Intakes for Calcium and Vitamin D By Institute of Medicine, Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, it is over 1000 pages detailing the work of 14 experts. It is a tertiary source on vitamin D. To contradict it in the article you need something more than a secondary source. Overagainst (talk) 14:01, 5 November 2011 (UTC)

Unless I'm reading the wrong abstract, I don't see a contradiction between what the Lancet article is saying and what the IoM is saying. Take particular note of the qualifyer " but there are uncertainties". And that's exactly what the IoM says. They didn't really dispute findings such as in the Lancet article pointing to positive health effects, what the did was to test if there is something beyond bone health for which the evidence can now be said to be "solid". And the conclusion is that as of yet, there isn't. That's 100% consistent with the Lancet article, they don't say that positive health effects for MS is a settled matter. Count Iblis (talk) 15:59, 5 November 2011 (UTC)

About how vitamin D exerts a protective effect:

"While for years scientists have noted an association between levels of vitamin D in a person's body and the person's ability to resist or minimize the effects of multiple sclerosis (MS), the mechanism involved has not been established. However new research by Sylvia Christakos, Ph.D., of UMDNJ-New Jersey Medical School (principal investigator) Sneha Joshi (first author, a UMDNJ Ph.D. student), and colleagues (including co-investigator Lawrence Steinman, MD, of Stanford University) appears to have uncovered that process. The study, published in the journal Molecular and Cellular Biology, finds that vitamin D directly terminates the production of a disease-causing protein.

During MS ("EAE" in mice), a damaging protein called interleukin-17 (IL-17) is produced by immune cells in the brain. The investigators, a collaborative team of scientists from the University of Medicine and Dentistry of New Jersey and Stanford University, find that after vitamin D binds to its receptor, the receptor parks itself on the gene that encodes IL-17. By doing so, the receptor occupies a site normally reserved for a protein called NFAT, which is required to turn the gene on. The gene stays off and IL-17 levels plummet.

At the same time, the vitamin D receptor turns on another gene, whose product generates suppressive T cells that combat the destructive action of their IL-17-producing counterparts.

According to the researchers, the mechanism they identify suggests what might be a new path toward pharmaceutical treatment of MS, as well as therapies for other autoimmune diseases that might include rheumatoid arthritis, type 1 diabetes, eczema and psoriasis."

Count Iblis (talk) 16:13, 5 November 2011 (UTC)

May I draw editors' attention to the recent reviews at PMID 20584945 and PMID 21333483? Both are by the same authors at different journals and dates. I would also point out that the IOM book's discussion of MS and Vitamin D (on pp.174-5) cites references no later than 2009. LeadSongDog come howl! 16:50, 5 November 2011 (UTC)

LeadSongDog, Hector DeLuca check out the page. Now, DeLuca on MS and UV he casts considerable doubt on the idea that D levels are the key factor. You can cherry pick a review article for almost any viewpoint. The IoM looked at only the biggest and best studies and analysed them very carefully, their conclusions are reliable. The highest quality studies are still valid years later.

Count Iblis, you keep saying that the IoM didn't really say what they said or mean what they said. Let's just read what these bunch of ... of... well experts actually, put in their report.

"Despite the many claims of benefit surrounding vitamin D in particular, the evidence did not support a basis for a causal relationship between vitamin D and many of the numerous health outcomes purported to be affected by vitamin D intake" So the sections on cancer, TB, cardiovascular health, Influenza ect ect are now established to be just plain wrong. "Despite the many claims of benefit surrounding vitamin D in particular, the evidence did not support a basis for a causal relationship between vitamin D and many of the numerous health outcomes purported to be affected by vitamin D intake[...] Although ensuring adequacy is important, there is now an emerging issue of excess vitamin D intakes. A congruence of diverse data on health outcomes ranging from all-cause mortality to cardiovascular risk suggests that adverse health outcomes may be associated with vitamin D intakes that are much lower than those classically associated with hypervitaminosis D and that appear to occur at serum 25OHD levels achievable through current levels of supplement use".Implications and Special Concerns

The IoM found no benefit and indications of risk from supplementation. If you want to read about what the found out about multiple sclerosis specifically here is an interview with a panel member Panel Clarifies Advice On Vitamin D Intake

"Clifford Rosen "Dr. Rosen, I remember an article over the summer in the New York Times, and it was about how most of us are vitamin deficient, that the average person should have about 30 nanograms of Vitamin D for every milliliter of blood. It included recommendations to spend at least five to 10 minutes in the sunshine, without sunscreen, three times a week.

And I must confess, I started to do that almost immediately after reading the article. Those recommendations came from Dr. Michael Holick at Boston University. You're now saying all that is unnecessary. What are the rest of us to make of these different recommendations? I mean, it's very confusing.

Dr. ROSEN: It is confusing. And Michael is a good friend of mine and a colleague, and mentored me in my early stages of my career. And he's done a lot for the Vitamin D field, and he's really brought it to the attention of both bone health experts and also others.

So I would just argue that I think we found that 20 nanograms per ML was very sufficient to maintain skeletal health. And indeed, more is not better. And we found no evidence that Vitamin D had effects on other disease states.

RAZ: Like cancer.

Dr. ROSEN: Like cancer or heart disease or neurological diseases or multiple sclerosis. When we started the report, we had over 30 disorders - from autism all the way to multiple sclerosis - that we were looking at to see if there were associations.

RAZ: Well, what's the downside of taking too much?

Dr. ROSEN: Well, that's what got us a little worried. As we got into the report, we actually saw that when levels of Vitamin D got too excessive, not only was the blood calcium increased, but we started to see a signal that suggested you might be at increased risk for other diseases -including, surprisingly enough, fractures.

RAZ: So don't take 5,000 units of Vitamin D a day; that's your recommendation.

Dr. ROSEN: That's definitely our recommendation."

The WP article on vitamin D should give proper weight to the scientific body whose reports are generally seen as authoritative. It can be mentioned that some researchers disagree with them of course, but what is the point of a "Health Effects" section with a laundry list of health effects referenced to secondary sources when the authoritative IoM report, which is a tertiary source, has discredited the idea of health effects other than bone health. Cut to the chase. The dissent is from lesser authorities and that must be reflected in the prominence given to them when they are mentioned in the article. The best layout is the 'Health outcomes' section which started off by explaining how and why the IoM report was authoritative (it is) and gave their conclusions using direct quotes.Overagainst (talk) 20:49, 5 November 2011 (UTC)

I will ask for clarification on the secondary verses tertiary issue at WP:MEDRS. This is not at all like the primary/secondary source issue. Also can people please just quote text from review articles rather than "medical news sites" or "interviews with authors". As Leadsong states the Lancet paper is more recent. I have added the two reviews LeadSong mentions.Doc James (talk · contribs · email) 13:49, 6 November 2011 (UTC)

Vitamin D overdose (moved)

Overdosing on Vitamin D is easier than you may think Dietary Reference Intakes for Calcium and Vitamin D (2011) p.436"large-scale pooled analysis (n = 2,285) found a statistically significant two-fold increased risk for pancreatic cancer in participants withserum 25OHD levels at or above 100 nmol/L compared with those with levels between 50 to 75 nmol". 100 nmol/L = 40ng/ml. (ie less 40 to 80 ng/mL which some say is the optimum range) Overagainst (talk) 17:33, 8 November 2011 (UTC)

That's not how "vitamin D overdose" is conventionally defined. Also, even if you wanted to redefine what "overdose" should mean, the fact that you are at a higher risk of developing pancreatic cancer if your calcidiol level is higher than 100 nmol/l (assuming that this is actually a fact) isn't evidence that such calcidiol levels are too high. Lowering the chance of getting certain diseases can sometimes be achieved by doing something that moves the body away from normal parameters. You can lower the chance of getting a heart attack by making your blood thinner than normal. You can also use statins to get abnormally low cholesterol level to lower that risk even further. You can restrict your calorie intake to less than 1500 Kcal per day to dramatically lower the risk of many diseases. Count Iblis (talk) 19:18, 8 November 2011 (UTC)

This whole focus on "authority" is wrong. In science we do need to resort to authority to some degree, but this is a necessary evil. It's far better to focus in the specific issues and cite the scientific arguments that they are based on. That the IoM report and other review articles will be given more weight is clear, but that's not the most important issue when writing the article.

E.g. Overagainst quoted from the IoM report "...there is now an emerging issue of excess vitamin D intakes". But then, if the IoM report is to be considered as a tertiary article, then it shouldn't be difficult to quote many review articles where this conclusion is also reached. But such articles don't exist, therefore this is a new conclusion based on a meta analysis performed by the IoM. From a scientific POV this statement should have the status of a primary research result. Pooling together research results from papers to reach a novel conclusion is not simply a review of the individual papers. The IoM not only performed their own statistical analysis, they even disagreed with the authors of individual papers about the conclusions of those papers.

So, on some issues, statements in the IoM report cannot be presented as if it gives the scientific consensus that existed at the time. But that doesn't mean that we can't include those statements from the IoM report. We can, but we need to put the statements in the proper context. By using the IoM report at all for some of the controversial statments they make, we are already giving it a far larger weight than we would give other papers that would make similar claims.

E.g., had the IoM report not appeared yet and had some other author done exactly what the IoM had done to reach the conclusion that "..there is now an emerging issue of excess vitamin D intakes", no one would even have suggested that this merits inclusion in Wikipedia, at least not before that paper would be widely cited. The very fact that this statement is controversial and contradicts the opinion of most researchers, would be a strong argument against including the statement. Clearly, then, the fact that the statement is currently included in Wikipedia and no one suggests that it should be removed, implies that the editors there are already giving the IoM report a much larger weight than any other article. Count Iblis (talk) 19:07, 8 November 2011 (UTC)

Why are people reverting back to a version with way too many primary studies?

Per WP:MEDRS, WP:PSTS, and WP:DUE, we should be avoiding using primary studies. I am at a complete loss as to why people keep removing secondary reviews and adding back primary studies. Yobol (talk) 22:03, 15 November 2011 (UTC)

Yes so am I.--Doc James (talk · contribs · email) 03:06, 16 November 2011 (UTC)

Published studies, if peer-reviewed, are not considered by WP to be completely primary, and by WP standards, very reliable. The introduction and conclusions are generally considered secondary sources, and therefore the journal article itself can be used extensively, provided the majority of the information is coming from the introduction or conclusions, which most in a WP article should. See Examples of Overlap of Primary and Secondary Material in a Single Source and Use of peer-reviewed sources.

I should note that I have not yet looked through this article to see what was used and what wasn't, but it's easy to think that entire peer-reviewed journal articles are completely primary when most of them aren't. The Haz _talk 03:47, 16 November 2011 (UTC)

The conclusion section of any novel study producing new results is primary by any definition, and it is this section that is being used here. They are clearly primary sources for the conclusion of that study, and should be avoided per WP:MEDRS. They also violate WP:DUE, as there are literally thousands of studies on vitamin D, and cherry picking which ones to discuss creates an WP:UNDUE problem. Yobol (talk) 03:50, 16 November 2011 (UTC)

I'm sorry but I can't agree with you there. First, the WP guideline I linked to above states that the conclusion of a peer-reviewed journal article is considered a secondary source. In my own opinion (as someone who is actually in a class on critically reading medical journal articles), I believe that most, but not all, statements in a conclusion can be considered secondary. They are heavily peer-reviewed and therefore almost as if the reviewer is writing them (which in many cases is exactly what happens when something is sent back for a rewrite). Theoretically, the reviewer would not have let the conclusion go to press if he/she didn't also come to the same conclusion based on the data. The Haz _talk 04:07, 16 November 2011 (UTC)

I have not seen Haz's definitions supported by the literature. Are there refs that say this? See review article... --Doc James (talk · contribs · email) 03:56, 16 November 2011 (UTC)

Since Haz has not even read the article to see if their comments are even applicable to this situation, might I suggest that Haz take this discussion to somewhere else so that we can focus on improving the article. Yobol (talk) 03:58, 16 November 2011 (UTC)

Actually right after writing that, I read the article and tried replying to you (edit conflict). My conclusion is that while some use data that can be considered primary (which don't forget is okay in WP--an article just cannot be majority primary), many also use the introductory material. However, I strongly agree with Yobol in that people should not be deleting secondary sources if they're there. That's just a shameful practice by any means. The Haz _talk 04:06, 16 November 2011 (UTC)

I don't know much about Vitamin D, but I do think it's clearly wrong that introductions and conclusions of individual published primary sources are secondary sources. As an academic, that's neither how we review nor how we write articles; the conclusions of a study are explicitly expected to be its own conclusions, and may not be consensus that everyone agrees with, so long as they pass the bar of being "worth publishing". Introductions and "future work" sections are even worse, often containing outright opinion or speculation that may not be held by anyone besides the authors. --Delirium (talk) 04:02, 16 November 2011 (UTC)

The "discussion" section of a primary research paper contains material which is usually a sort of targetted "mini-review" of the literature, commenting on other people's results and attempting a synthesis of the results of the present study with those of others. Sometimes for WP purposes, this section can thus be useful, inasmuch as it often covers material too new to be in texts, and for which there IS NO dedicated review article available in the literature yet, but here you can still seize the chance to quote somebody's synthetic opinion on a point-- an opinion which is in peer-reviewed print. Furthermore, I don't necessarily think that the quality of such statements, so long as they aren't taken too broadly, is worse than what you find in peer-reviewed dedicated reviews. You may complain that the writer of a primary paper is being rather biased in their very selective citation of other works that resemble the one they are presenting-- and so they are. But "dedicated reviews" are often not a lot better, and almost always have some obvious axe to grind. Too often they've been mined from the writer's last grant proposal, so they started out as material that was arguing toward a synthetic purpose ("why you should give me money") from the get-go. In fact, sometimes it's worse if this is partly hidden. At least in a grant proposal, or a primary paper intro (or discusssion), we know what the authors' purpose is: it's to make his own work shine. In a dedicated review, that may not be quite so apparent to the reader, even if the writer is still at it.

Anyway, if nothing else better is available, some of this primary material is useful. That is not to say that it should replace dedicated really-good reviews, where they exist. I'm only pointing out that we can't denigrate all parts of primary literature. The main reason is that not all scientists who are tops in their fields (the real experts) actually write that many dedicated reviews that we can use. Instead, you'll find their opinions and surveys of their own fields-- what they choose to do of this-- in the discussion sections of their own primary research papers! Are we to throw all that out the window, in favor of textbooks written by nonworking scientists, and perhaps even reviews written by people who did NOT get the grant, and didn't get a good primary study published, but needed a publication to pad a CV anyway? It's a legitimate question. SBHarris 04:31, 16 November 2011 (UTC)

That's an excellent comment and some of that should be grafted into WP:MEDRS. Primary studies have their place!  Jabbsworth  05:47, 16 November 2011 (UTC)

Of course we shouldn't avoid citing the intro or discussion section of primary literature as a secondary source. Ideally, the person making the citation should know whether or not they are using it as a secondary source or primary source. Jesanj (talk) 05:19, 16 November 2011 (UTC)

It is a reasonable question but one which the research from my reading does not support.Doc James (talk · contribs · email) 04:03, 16 November 2011 (UTC)

Yeah, well I just realized that the page I was reading was a failed proposal (something you miss when links only go to anchors). Therefore I'll strike some of my comments above. However, WP:NOR still states that In general, the most reliable sources are: peer-reviewed journals[...] which I think can be used to accommodate at least the introduction. Again though, to make myself clear, I still prefer secondary reviews of studies, though they could really be no more reliable than the journal article itself. The Haz _talk 04:23, 16 November 2011 (UTC)

Indeed so, and for the reasons I note just above. SBHarris 04:32, 16 November 2011 (UTC)

• (ec)Haz touches on an valid point though which is mentioned in WP:MEDRS, there are mixes of primary and secondary sources, particularly when a primary source contains a review section concerning previous research, per WP:MEDRS:

Research papers that describe original experiments are primary sources; however, they normally contain previous-work sections that are secondary sources (these sections are often incomplete and typically less useful or reliable than reviews or other sources, such as textbooks, which are intended to be reasonably comprehensive).

To get other editors to join into this discussion you should provide some diffs or elaborate further on the issue here because it's not readily apparent, and comments to editors newly joining like these "might I suggest that Haz take this discussion to somewhere else so that we can focus on improving the article" are not at all helpful. Is this the diff you are referring to? It would be much more comprehensible if you just gave a list of the current primary sources and a list of the secondary sources you are trying to replace them with; the diff is hard to read with the wiki markup and mass moving of text, and on the surface it appears as though you have deleted 1/5 the article and inserted an external link to a Vitamin D advocacy group.AerobicFox (talk) 04:49, 16 November 2011 (UTC)

If there where no recent review articles than yes I would agree we would have to use the introduction or summary of primary research articles. However pubmed lists more than 7000 review articles dealing with vitamin D many of which are published in the last couple of years. There is thus little justification for using any part of a primary research paper in this case. Have provided some difs below. --Doc James (talk · contribs · email) 13:03, 16 November 2011 (UTC)

Summary of the evidence

I have added the following summary of the evidence on vit D

The evidence for the health effects of vitamin D supplementation in the general population is inconsistent. The best evidence of benefit is for bone health and a decrease in mortality in elderly women.

This is based on 5 secondary sources / review articles published in the last 3 years.Doc James (talk · contribs · email) 12:44, 16 November 2011 (UTC)

Cancer

Previously we stated

===Cancer===

The molecular basis for thinking that vitamin D has the potential to prevent cancer lies in its role in a wide range of cellular mechanisms central to the development of cancer. These effects may be mediated through vitamin D receptors expressed in cancer cells. Polymorphisms of the vitamin D receptor (VDR) gene have been associated with an increased risk of breast cancer. Women with mutations in the VDR gene had an increased risk of breast cancer.

A 2006 study using data on over 4 million cancer patients from 13 different countries showed a marked increase in some cancer risks in countries with less sun and another metastudy found correlations between vitamin D levels and cancer. The authors suggested that intake of an additional 1,000 international units (IU) (or 25 micrograms) of vitamin D daily reduced an individual's colon cancer risk by 50%, and breast and ovarian cancer risks by 30%. Low levels of vitamin D in serum have been correlated with breast cancer disease progression and bone metastases. However, the vitamin D levels of a population do not depend on the solar irradiance to which they are exposed. Moreover, there are genetic factors involved with cancer incidence and mortality which are more common in northern latitudes.

A 2006 study found that taking the U.S. RDA of vitamin D (400 IU per day) cut the risk of pancreatic cancer by 43% in a sample of more than 120,000 people from two long-term health surveys. However, in male smokers a 3-fold increased risk for pancreatic cancer in the highest compared to lowest quintile of serum 25-hydroxyvitamin D concentration has been found.

A randomized intervention study involving 1,200 women, published in June 2007, reports that vitamin D supplementation (1,100 international units (IU)/day) resulted in a 60% reduction in cancer incidence, during a four-year clinical trial, rising to a 77% reduction for cancers diagnosed after the first year (and therefore excluding those cancers more likely to have originated prior to the vitamin D intervention). The study was criticized on several grounds including lack of reported data, use of statistical techniques and comparison with a self-selected (i.e. non-randomized) observational study that found long term convergence of breast cancer incidence (i.e. the cancer occurrence had merely been delayed) The author's response provided the requested data, explained their statistical usage and commented that even if the vitamin D merely delayed the appearance of cancer (which they did not believe, based on other studies), that this was still a considerable benefit.

In 2007, the Canadian Cancer Society recommended that adults living in Canada should consider taking vitamin D supplementation of 1,000 international units (IU) a day during the fall and winter. A US National Cancer Institute study analyzed data from the third national Health and Nutrition Examination Survey to examine the relationship between levels of circulating vitamin D in the blood and cancer mortality in a group of 16,818 participants aged 17 and older. It found no support for an association between 25(OH)D and total cancer mortality. However, the study did find that "[c]olorectal cancer mortality was inversely related to serum 25(OH)D level, with levels 80 nmol/L or higher associated with a 72% risk reduction (95% confidence interval = 32% to 89%) compared with lower than 50 nmol/L, P_trend = .02." Unlike other studies, this one was carried out prospectively— meaning that participants were followed looking forward — and the researchers used actual blood tests to measure the amount of vitamin D in blood, rather than trying to infer vitamin D levels from potentially inaccurate predictive models.

A meta-study published in the International Journal of Cancer in May 2010 analyzed 35 independent studies of vitamin D and cancer. The researchers determined that a 10 nanogram/milliliter increase in serum vitamin D is associated with a 15% lower risk of colon cancer. The analysis also found an 11% lower risk for breast cancer, although the authors report that due to case study methodology that this finding is ultimately insignificant.

A 2011 study done at the University of Rochester Medical Center found that low vitamin D levels among women with breast cancer correlate with more aggressive tumors and poorer prognosis. The study associated sub-optimal vitamin D levels with poor scores on every major biological marker that helps physicians predict a patient’s breast cancer outcome. The lead researcher stated, “Based on these results, doctors should strongly consider monitoring vitamin D levels among breast cancer patients and correcting them as needed.”

This has been summarized using two review articles published in the last 3 years having removed all the primary research which is taking into account by these reviews

Low vitamin D levels are associated with some cancers. When supplementation is used to treat people with prostate cancer, however, there does not appear to be a benefit. Results for a protective or harmful effect of vitamin D supplementation in other types of cancer are inconclusive.

Doc James (talk · contribs · email) 12:48, 16 November 2011 (UTC)

Much of the first passage deals with the mechanism of action of vitamin D rather than its health effects.Doc James (talk · contribs · email) 12:50, 16 November 2011 (UTC)

Two sections on health outcomes

Before we had two sections on health outcomes. One called "health effects" and the other called "vitamin D and health outcomes". I have merged these two sections as they basically deal with the same thing into a section called "health effects.Doc James (talk · contribs · email) 12:58, 16 November 2011 (UTC)