Conclusions Vitamin D supplementation did not improve EF .
The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function .
Abstract Background In addition to regulating calcium homoeostasis and bone health , vitamin D influences vascular and metabolic processes including endothelial function ( EF ) and insulin signalling .
No Effect of High-Dose Vitamin D Supplementation on Glycemic Status or Cardiovascular Risk Factors in Subjects With Prediabetes
OBJECTIVE In observational studies , low serum 25-hydroxyvitamin D [ 25(OH)D ] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease . RESEARCH DESIGN AND METHODS We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose ( IFG ) and /or impaired glucose tolerance ( IGT ) r and omly assigned to 20,000 IU/week vitamin D3 or placebo .  An oral glucose tolerance test was performed at baseline and after 1 year . RESULTS Mean baseline serum 25(OH)D was 59.9 nmol/L and 61.1 nmol/L in the vitamin D and placebo groups , respectively , and increased by 45.8 nmol/L and 3.4 nmol/L , respectively . With adjustment for baseline concentrations , no differences in measures of glucose metabolism , insulin secretion or sensitivity , blood pressure , or hs-CRP were found after 1 year . There was a slight , but significant decrease in total and LDL cholesterol in the vitamin D group compared with the placebo group , but as there was also a decrease in HDL cholesterol , the change in the total/HDL cholesterol ratio did not differ significantly . Only analyzing subjects with 25(OH)D < 50 nmol/L did not change the results . CONCLUSIONS This study shows that vitamin D supplementation does not improve glycemic indices , blood pressure , or lipid status in subjects with IFG and /or IGT
Conclusions Vitamin D supplementation did not improve EF .
The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function .
Abstract Background In addition to regulating calcium homoeostasis and bone health , vitamin D influences vascular and metabolic processes including endothelial function ( EF ) and insulin signalling .