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 .
A global representation of vitamin D status in healthy populations
Purpose This paper visualizes the available data on vitamin D status on a global map , examines the existing heterogeneities in vitamin D status and identifies research gaps . Methods A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011 . Studies were eligible if they included sample s of r and omly selected males and females from the general population and assessed  circulating 25-hydroxyvitamin D [ 25(OH)D ] levels .  Two different age categories were selected : children and adolescents ( 1–18 years ) and adults ( > 18 years ) . Studies were chosen to represent a country based on a hierarchical set of criteria . Results In total , 200 studies from 46 countries met the inclusion criteria , most coming from Europe . Forty-two of these studies ( 21 % ) were classified as representative . In children , gaps in data were identified in large parts of Africa , Central and South America , Europe , and most of the Asia/Pacific region . In adults , there was lack of information in Central America , much of South America and Africa . Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L. Conclusions This study provides an overview of 25(OH)D levels around the globe . It reveals large gaps in information in children and adolescents and smaller but important gaps in adults . In view of the importance of vitamin D to musculoskeletal growth , development , and preservation , and of its potential importance in other tissues , we strongly encourage new research to clearly define 25(OH)D status around the world
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 .