Background learning, for me, on Vitamin D and diabetes #wddty

Doctors, skeptics and science twitterers / bloggers across the land have had their interest piqued by Lynne McTaggart's magazine "What Doctors Don't Tell You" which has recently become available in highstreet shops after being subscription only (since 1989). The front cover itself is full of snappy hyperbole but the contents are also promoting health advice that may well be rooted in a rather selective pick of the evidence.

I've written before on diabetes and vitamin D and answered a fair few questions on it from members of the public and healthcare professionals when I used to work at Diabetes UK. It looks like I might enjoy revisiting this so, rather than just write the finished blog post ("What Doctors Don't Tell You didn't tell you about Vitamin D and diabetes" sounds snappy) I thought I'd 'show my workings' as I investigate this.

Below, in reverse order, is what I've been looking at. I suspect I'm in for the long haul on this one.

Day One - 6 October 2012 - early afternoon

Front cover: "Sunbathe your diabetes away" - this seems to be saying that sunbathing can get rid of your diabetes which... is a bit troubling.

Article title: in the Prevention section (so that's not quite the same as getting rid of) "D is for diabetes; the sunshine supervit" - OK nothing wrong with that title.

Article content - I'm ignoring the claims in the article for the time being, plenty more on that later.

References: The article in WDDTY is referenced. It cites several peer-reviewed articles that are published in journals I've heard of - one, Diabetes Care, is actually the house journal of the American Diabetes Association. The references aren't from the Journal of Utter Nonsense, which is a good start.

My questions / thoughts on this include - how were these articles selected (what was the search strategy used that resulted in these references being chosen), do these articles tell the whole story and were the full articles obtained or just the abstracts read.

In almost all journal papers there's a free abstract available but it can often cost money to read the whole thing. Quite a few journals make their articles free after one year but there are nearly always ways of getting hold of free copies (emailing the author for one thing, often works rapid wonders).

If articles are freely available to those without subscription then the advantage is that the full article was probably read but my concern would be that these were chosen because they were freely available (and makes me wonder what non-freely available published research was ignored), or where just the abstracts were read. It feels a bit mean to be considering criticising a publication that's referenced research that's largely freely available!

It also costs a bit of mental processing to fully understand the article and to know what conclusions can be drawn from it - helpful to have a bit of background knowledge about the overall field of diabetes and Vit D to draw on too.

The references are, with further details below:

1. Diabetes Care, 2011, 34 - 1133-1138 (full PDF)

2. Diabetes Care, 2007, 30 - 2569-2570 (full PDF)

3. Diabetes Care, 2006, 29 - 650-664 (full PDF)

4. Am J Clin Nutr, 2011, 93 - 764-771 (full PDF)

5. Diabetes Metab Res Rev, 2009, 25 - 417-419 (paywalled link to PDF, possibly the article includes this preceeding article in its commentary, on Vitamin D and LADA)

6. Curr Diab Rep, 2008, 8 - 393-398 (not found PDF but this is the abstract) and
    Diabetes Care, 2011, 34 - 1081-1085 (full PDF)

7. Lancet, 2001, 358 - 1500-1503 (abstract only, also related article commentary abstract)

8. Arch Dis Child, 2008, 93 - 512-517 (full PDF)

9. Diabetes Care, 2009, 32 - 1278-1283 (full PDF)

I'm on a computer that's not currently logged in to any academic or other network so I can only access full articles that everyone can access at the moment. Of the above 10 articles cited (number 6 mentions two articles) I was able to get full PDF or web versions for seven of them.


1. Serum 25-Hydroxyvitamin D, Calcium Intake, and Risk of Type 2 Diabetes After 5 Years: Results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle study)Claudia Gagnon,  Zhong X. Lu,  Dianna J. Magliano,  David W. Dunstan, Jonathan E. Shaw,  Paul Z. Zimmet,  Ken Sikaris,  Narelle Grantham, Peter R. Ebeling,  and Robin M. Daly
Diabetes Care May 2011 34:1133-1138; published ahead of print March 23, 2011, doi:10.2337/dc10-2167
Original Research - Epidemiology/Health Services Research

2. Serum 25-Hydroxyvitamin D Concentration and Subsequent Risk of Type 2 Diabetes
Catharina Mattila,  Paul Knekt,  Satu Männistö,  Harri Rissanen, Maarit A. Laaksonen,  Jukka Montonen,  and Antti Reunanen
Diabetes Care October 2007 30:2569-2570; published ahead of printJuly 12, 2007, doi:10.2337/dc07-0292
Epidemiology/Health Services Research

3. Vitamin D and Calcium Intake in Relation to Type 2 Diabetes in Women
Anastassios G. Pittas,  Bess Dawson-Hughes,  Tricia Li,  Rob M. Van Dam, Walter C. Willett,  Joann E. Manson,  and Frank B. Hu
Diabetes Care March 2006 29:650-656;doi:10.2337/diacare.29.03.06.dc05-1961
Cardiovascular and Metabolic Risk

4. Daily consumption of vitamin D– or vitamin D + calcium–fortified yogurt drink improved glycemic control in patients with type 2 diabetes: a randomized clinical trial
Bahareh Nikooyeh, Tirang R Neyestani, Maryamosadat Farvid, Hamid Alavi-Majd, Anahita Houshiarrad, Ali Kalayi, Nastaran Shariatzadeh, A'azam Gharavi, Soudabeh Heravifard, Nima Tayebinejad,
Shabnam Salekzamani, and Malihe Zahedirad
Am J Clin Nutr 2011 93: 764-771;  First published online February 2, 2011.  doi:10.3945/ajcn.110.007336

5. Vitamin D in diabetes mellitus—a new field of knowledge poised for D-velopment
(pages 417–419)
B. Alfonso, E. Liao, A. Busta and L. Poretsky
Article first published online: 29 JUN 2009 | DOI: 10.1002/dmrr.927

6a. Diabetes and the vitamin d connection.
Curr Diab Rep. 2008 Oct;8(5):393-8.
Holick MF.

6b. Vitamin D Levels, Microvascular Complications, and Mortality in Type 1 Diabetes
Christel Joergensen,  Peter Hovind,  Anne Schmedes,  Hans-Henrik Parving, and Peter Rossing
Diabetes Care May 2011 34:1081-1085; doi:10.2337/dc10-2459
Original Research - Clinical Care/Education/Nutrition/Psychosocial Research

7. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study
Elina Hyppönen, Esa Läärä, Antti Reunanen, Marjo-Riitta Järvelin, Suvi M Virtanen

8. Vitamin D supplementation in early childhood and risk of type 1 diabetes: a systematic review and meta-analysis
C S Zipitis, A K Akobeng
Arch Dis Child 2008;93:512-517 Published Online First: 13 March 2008doi:10.1136/adc.2007.128579

9. Plasma 25-Hydroxyvitamin D Concentration and Metabolic Syndrome Among Middle-Aged and Elderly Chinese Individuals
Ling Lu,  Zhijie Yu,  An Pan,  Frank B. Hu,  Oscar H. Franco,  Huaixing Li, Xiaoying Li,  Xilin Yang,  Yan Chen,  and Xu Lin
Diabetes Care July 2009 32:1278-1283; published ahead of print April 14, 2009, doi:10.2337/dc09-0209
Original Research - Cardiovascular and Metabolic Risk