This meta- analysis concludes that hypovitaminosis D is associated with increased risk of hyperglycemia both in diabetic and non-diabetic subjects .
There is evidence that vitamin D status is associated with type 2 diabetes .
Many observational studies have been performed investigating the relationship of vitamin D status and circulating biomarkers of glycemic regulation .
To find out whether this association holds , we conducted a systematic review and meta- analysis of cross sectional and longitudinal studies .
Plasma 25-hydroxyvitamin D and its genetic determinants in relation to incident type 2 diabetes: a prospective case-cohort study
It is unclear whether vitamin D lowers risk of type 2 diabetes ( T2D ) . In an observational study , we assessed the prospect i ve association between plasma  25-hydroxyvitamin D ( 25(OH)D )  and incident T2D  , and evaluated whether it holds up for genetically determined elevated 25(OH)D. We used a case-cohort study nested within the German arm of the European Prospect i ve Investigation into Cancer . From a total cohort of 53,088 participants with a mean follow-up of 6.6 years , we identified a r and om subcohort of 2,121 participants ( 57 % women ) and 1,572 incident cases of T2D .  25(OH)D was measured in baseline plasma sample s retrieved from frozen storage . Mean plasma 25(OH)D in the subcohort was 47.1 ( 5th–95th percentile 19.6–80.7 ) nmol/L. After controlling for age , sex , center , season of blood draw , education , and lifestyle , the hazard of T2D decreased across increasing plasma concentrations of 25(OH)D ( P linear trend < 0.0001 ) . The association became non-linear after adjustment for BMI and waist circumference ( P non-linearity < 0.0001 ) , with the inverse association being restricted to participants with 25(OH)D concentrations below ~45 nmol/L ( hazard ratio per 5 nmol/L higher 25(OH)D 0.91 , 95 % CI 0.84–0.98 ) . A score predicting genetically determined plasma 25(OH)D by weighting four independent single-nucleotide polymorphisms by their effect on 25(OH)D , explained 3.7 % of the variance in 25(OH)D. The hazard ratio ( 95 % CI ) per 5 nmol/L higher genetically predicted 25(OH)D was 0.98 ( 0.89–1.08 ) in the entire study sample and 1.06 ( 0.93–1.21 ) in the sub- sample with 25(OH)D < 45 nmol/L. This latter finding casts doubt on a strong causal association of 25(OH)D with T2D , but further research in large-scale consortia is needed
This meta- analysis concludes that hypovitaminosis D is associated with increased risk of hyperglycemia both in diabetic and non-diabetic subjects .
There is evidence that vitamin D status is associated with type 2 diabetes .
Many observational studies have been performed investigating the relationship of vitamin D status and circulating biomarkers of glycemic regulation .
To find out whether this association holds , we conducted a systematic review and meta- analysis of cross sectional and longitudinal studies .