Background: 25-hydroxyvitamin D and irisin have been found to be involved in the pathogenesis of obesity. The aim of the study is to assess the serum levels of 25-hydroxyvitamin D and irisin in obese patients and to determine the association of 25-hydroxyvitamin D and irisin levels with anthropometric parameters.
Methods: The study was carried out on 300 obese patients in addition to 156 healthy age and gender matched subjects as a control group. Demographic data were collected from the studied cases. Body mass index, serum levels of insulin, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, 25-hydroxyvitamin D, and irisin were measured.
Results: 25-hydroxyvitamin D levels were significantly associated with obesity, the incidence of 25-hydroxyvitamin D deficiency (< 12 ng/mL) was 49.3% in obese patients, especially in females. A positive correlation was noted between 25-hydroxyvitamin D and age TC:HDL ratio. It was negatively correlated with BMI. Serum irisin levels were higher, but not significantly, in obese patients compared to controls. Irisin was positively associated with insulin levels and negatively correlated with total cholesterol.
Conclusions: Obesity is associated with 25-hydroxyvitamin D deficiency and high serum levels of irisin. Body mass index and gender are predictors of 25-hydroxyvitamin D status. The positive correlation between serum irisin and insulin indicates that compensatory enhancement of irisin excretion can occur due to insulin resistance.