4 percent less type 2 diabetes for every 4 ng more vitamin D – meta-analysis May 2013

Blood 25-Hydroxy Vitamin D Levels and Incident Type 2 Diabetes: A meta-analysis of prospective studies.

Diabetes Care. 2013 May;36(5):1422-8. doi: 10.2337/dc12-0962.
Song Y, Wang L, Pittas AG, Del Gobbo LC, Zhang C, Manson JE, Hu FB.
Corresponding author: Yiqing Song, ysong3 at rics.bwh.harvard.edu.

OBJECTIVE To quantitatively assess the strength and shape of the association between blood 25-hydroxy vitamin D [25(OH)D] levels and incident risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS A systematic search of the MEDLINE and Embase databases and a hand search of references from original reports were conducted up to 31 October 2012. Prospective observational studies that assessed the association between blood levels of 25(OH)D and risk of incident type 2 diabetes were included for meta-analysis. DerSimonian and Laird's random-effects model was used. A quadratic spline regression analysis was used to examine the shape of the association with a generalized least-squares trend test performed for the dose-response relation.

RESULTS A total of 21 prospective studies involving 76,220 participants and 4,996 incident type 2 diabetes cases were included for meta-analysis. Comparing the highest to the lowest category of 25(OH)D levels, the summary relative risk for type 2 diabetes was 0.62 (95% CI 0.54-0.70). A spline regression model showed that higher 25(OH)D levels were monotonically associated with a lower diabetes risk.
This inverse association did not differ by sex, duration of follow-up, study sample size, diabetes diagnostic criteria, or 25(OH)D assay method.
A linear trend analysis showed that each 10 nmol/L increment in 25(OH)D levels was associated with a 4% lower risk of type 2 diabetes (95% CI 3-6; P for linear trend < 0.0001).

CONCLUSIONS Our meta-analysis showed an inverse and significant association between circulating 25(OH)D levels and risk of type 2 diabetes across a broad range of blood 25(OH)D levels in diverse populations.

PMID: 23613602
This article contains Supplementary Data online at http://care.diabetesjournals.org/lookup/suppl/doi:10.2337/dc12-0962/-/DC1.

Sample of the clinical trials

Supplementary data PDF is attached at the bottom of this page

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See also VitaminDWiki

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• Overview Metabolic Syndrome and vitamin D
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• Metabolic Syndrome 10% less likely for every 4 ng increase in Vitamin D – Jan 2013
• Type II Diabetes not reduced by 3 months of 5000 IU of vitamin D – RCT Jan 2013
• Diabetes 3.5X less likely if more than 25 ng Vitamin D – Sept 2012
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