Is There Any Relationship between Plasma 25-Hydroxyvitamin D(3), Adipokine Profiles and Excessive Body Weight in Type 2 Diabetic Patients?

A growing interest in the role of vitamin D in metabolic diseases led us to study the relationships between 25-hydroxyvitamin D(3) (25(OH)D(3)) and the profiles of selected adipokines in type 2 diabetic (T2DM) patients. The study comprised 92 type 2 diabetics divided into quartiles regarding 25(OH)D(3) concentration. Each group was divided into male and female subgroups. All the studied patients had their anthropometric and biochemical parameters determined. Plasma 25-hydroxyvitamin D(3) concentration was determined by HPLC, while the selected adipokines (leptin, adiponectin, resistin and visfatin) by ELISA methods. The ratio of leptin to adiponectin (L/A) was calculated for all the patients. In 85.3% of diabetics a full (<20 ng/mL) or moderate (20–30 ng/mL) vitamin D deficit was found. Irrespective of sex, plasma leptin concentration decreased across increasing quartiles of 25(OH)D(3) level. In women, 25(OH)D(3) was negatively correlated with BMI, leptin level as well as L/A ratio, and positively with adiponectin concentration. In men, 25(OH)D(3) was positively correlated with HDL and negatively with systolic blood pressure (SBP), leptin level and L/A ratio. Considering all the patients, there ocurred a significant negative correlation between 25(OH)D(3) and SBP, BMI, WHR, TG, leptin and L/A ratio and positive ones between 25(OH)D(3) and both adiponectin and HDL. The results of the study support the existence of the relationship among vitamin D, obesity and leptin in type 2 diabetic patients.