Current evidence indicates that inverse association between leptin level and 25(OH)D concentration was observed in observational studies , which was not demonstrated in intervention studies with high heterogeneity .
We aim ed to investigate the potential association between vitamin D and serum leptin levels by pooling together the results from observational studies and clinical trials .
The effect of cholecalciferol supplementation on vitamin D levels and insulin sensitivity is dose related in vitamin D-deficient HIV-1-infected patients.
OBJECTIVE The aim of this study was to explore the effects of cholecalciferol supplementation on vitamin D levels , bone mineral density ( BMD ) , body fat distribution and insulin sensitivity in vitamin D-deficient HIV-1-infected patients . METHODS Twenty vitamin D-deficient HIV-1-infected patients were prospect ively treated with 2000 IU cholecalciferol/day for 14 weeks , whereafter treatment was continued with half this dosage until 48 weeks . BMD , body fat distribution , 1,25-dihydroxy vitamin D(3 ) ( 1,25(OH)2D3 ) , fasting glucose , insulin , adiponectin , leptin , interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha were measured at baseline , and at 24 and 48 weeks . Parathyroid hormone ( PTH ) , 25-hydroxy vitamin D(3 ) [ 25(OH)D(3 ) ] , cholesterol and triglycerides were measured at baseline , and at 12 , 24 and 48 weeks . RESULTS After 24 weeks , cholecalciferol supplementation significantly increased 25(OH)D3 and 1,25(OH)2D3 levels and decreased PTH and insulin sensitivity . After 48 weeks , however , only 25(OH)D3 levels remained significantly different from baseline , while the other parameter levels returned to baseline , suggesting a dose-response effect . Cholecalciferol had no effect on BMD , adipokines and triglycerides . CONCLUSIONS The effect of cholecalciferol treatment in this cohort appears to be dose dependent . Cholecalciferol dosages of > or = 2000 IU are necessary to achieve 1,25(OH)2D3 levels that significantly decrease PTH , but also negatively affect insulin sensitivity . The results of this hypothesis-driven explorative study need to be confirmed in larger clinical trials
Current evidence indicates that inverse association between leptin level and 25(OH)D concentration was observed in observational studies , which was not demonstrated in intervention studies with high heterogeneity .
We aim ed to investigate the potential association between vitamin D and serum leptin levels by pooling together the results from observational studies and clinical trials .