Evidence from trials with vitamin D and /or calcium supplementation suggests that combined vitamin D and calcium supplementation may have a role in the prevention of type 2 DM only in population s at high risk ( i.e. glucose intolerance ) .
Vitamin D and calcium insufficiency may negatively influence glycemia , whereas combined supplementation with both nutrients may be beneficial in optimizing glucose metabolism
CONTEXT Altered vitamin D and calcium homeostasis may play a role in the development of type 2 diabetes mellitus ( type 2 DM ) .
Glucose intolerance is associated with altered calcium homeostasis: a possible link between increased serum calcium concentration and cardiovascular disease mortality.
Serum calcium concentration has recently been shown to predict cardiovascular mortality in a large health-screening program . Since impaired glucose tolerance ( IGT ) is an independent cardiovascular risk factor , we examined the association between glucose intolerance and serum calcium in a population -based cohort study . To characterize this association , we measured  total serum calcium , parathyroid hormone ( PTH ) , 25-hydroxyvitamin D ( 25OHD ) , and 1,25-dihydroxyvitamin D ( 1,25-(OH)2D ) levels  in a cohort of 1,071 r and omly selected white individuals aged 40 to 65 years in whom an oral glucose tolerance test had been completed . In multivariate analyses , the  2-hour plasma glucose  was positively associated with increasing total serum calcium and PTH in men and women after adjustment for age , obesity , season , and 25OHD . The adjusted odds ratio ( OR ) between increasing quintiles of total serum calcium and IGT was 1.63 ( 95 % confidence interval [ CI ] , 1.42 to 1.88 ) . The OR comparing the top with the bottom quintile was 8.5 ( 95 % CI , 4.5 to 16.0 ) . The association with quintile of serum PTH was 1.30 ( 95 % CI , 1.14 to 1.49 ) . These data suggest that IGT is associated with an increase in both total serum calcium and PTH that can not be explained by confounding by aging , obesity , or 25OHD . This relationship may explain the previously observed association between serum calcium and cardiovascular mortality . Whether this association is a manifestation of a shared cellular defect or represents a common relationship with an unknown etiologic factor are important questions for further research
Evidence from trials with vitamin D and /or calcium supplementation suggests that combined vitamin D and calcium supplementation may have a role in the prevention of type 2 DM only in population s at high risk ( i.e. glucose intolerance ) .
Vitamin D and calcium insufficiency may negatively influence glycemia , whereas combined supplementation with both nutrients may be beneficial in optimizing glucose metabolism
CONTEXT Altered vitamin D and calcium homeostasis may play a role in the development of type 2 diabetes mellitus ( type 2 DM ) .