Association of 25-hydroxy Vitamin D levels with indexes of general and abdominal obesity in Iranian adolescents: The childhood and adolescence surveillance and prevention of adult non-communicable disease-III study

This study aimed to determine the association of serum 25-hydroxy Vitamin D (25(OH)D) levels with measures of general and abdominal obesity in Iranian adolescents. This nationwide cross-sectional study was conducted among 1090 students, aged 10-18 years, living in 27 provinces in Iran. Serum concentration of 25(OH)D was analyzed quantitatively by direct competitive immunoassay chemiluminescence method. Body mass index (BMI) and waist-to-height ratio (WHtR) were considered as measures of generalized and abdominal obesity, respectively. Study participants consisted of 1090 adolescents (51.9% boy and 67.1% urban residents) with mean age, BMI, and waist circumference of 14.7 (2.6) years, 19.3 (4.2) kg/m2, and 67.82 (12.23) cm, respectively. The median serum 25(OH)D was 13.0 ng/mL (interquartile range: 20.6). Overall, 40% of participants were Vitamin D deficient, and 39% were Vitamin D insufficient. Serum 25(OH)D level was not associated with BMI and WHtR. We did not document any significant association between serum 25(OH)D level and anthropometric measures in adolescents. This finding may be because of considerably high prevalence of hypovitaminosis D in the study population.