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 .
Calcium-vitamin D cosupplementation influences circulating inflammatory biomarkers and adipocytokines in vitamin D-insufficient diabetics: a randomized controlled clinical trial.
CONTEXT To the best of our knowledge , no study has examined the effects of vitamin D-calcium cosupplementation on inflammatory biomarkers and adipocytokines in vitamin D-insufficient type 2 diabetics . OBJECTIVE This study was performed to assess the effects of vitamin D and calcium supplementation on inflammatory biomarkers and adipocytokines in vitamin D-insufficient people with type 2 diabetes . METHODS Totally , 118 diabetic patients were enrolled in this r and omized , placebo-controlled clinical trial . After matching for age , sex , body mass index , type and dose of hypoglycemic agents , and duration of diabetes , subjects were r and omly assigned into 4 groups receiving the following : 1 ) 50000 IU/wk vitamin D + calcium placebo ; 2 ) 1000 mg/d calcium + vitamin D placebo ; 3 ) 50 000 IU/wk vitamin D + 1000 mg/d calcium ; or 4 ) vitamin D placebo + calcium placebo for 8 weeks . Blood sampling was done for the quantification of inflammatory biomarkers and adipocytokines at the study baseline and after 8 weeks of intervention . RESULTS Calcium ( changes from baseline : -75 ± 19 ng/ml , P = .01 ) and vitamin D alone ( -56 ± 19 ng/mL , P = .01 ) and joint calcium-vitamin D supplementation ( -92 ± 19 ng/mL , P = .01 ) result ed in a significant reduction in serum leptin levels compared with placebo ( -9 ± 18 ng/mL ) . This was also the case for serum IL-6 , such that calcium ( -2 ± 1 pg/mL , P < .001 ) and vitamin D alone ( -4 ± 1 pg/mL , P < .001 ) and their combination ( -4 ± 1 pg/mL , P < .001 ) led to significant reductions compared with placebo ( 3 ± 1 pg/mL ) . After adjustment for potential confounders , individuals in the calcium ( -3.1 ± 1.3 , P < .05 ) , vitamin D ( -3.1 ± 1.3 , P < .05 ) , and joint calcium-vitamin D groups ( -3.4 ± 1.3 , P < .05 ) had greater reductions in serum TNF-α concentrations compared with placebo ( 0.1 ± 1.2 ) . Individuals who received joint calcium-vitamin D supplements tended to have a decrease in serum high-sensitivity C-reactive protein levels compared with placebo after controlling for baseline levels ( -1.14 ± 0.25 vs 0.02 ± 0.24 ng/mL , P = .09 ) . CONCLUSION Joint calcium-vitamin D supplementation might improve systemic inflammation through decreasing IL-6 and TNF-α concentrations in vitamin D-insufficient people with type 2 diabetes
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 .