Association of Vitamin D and Parathyroid Hormone Levels in Overweight and Obese Adolescents

Vitamin D deficiency in known to be high in obese and overweight adolescents. Few studies in other countries have shown lower parathyroid hormone (PTH) levels in obese adolescents despite high vitamin D deficiency. The aim of the study is to assess vitamin D and PTH levels and their relationship in overweight and obese adolescents in Telangana. This cross-sectional study was carried out in 108 overweight and obese boys and girls aged 12–18 years. A pretested Questionnaire was administered to collect information on demographics, sun exposure, medical and nutritional history. Anthropometry and blood sample was collected for estimating 25 hydroxy vitamin D, and PTH. Body mass index Z scores (WHO growth standards) were used for assessing overweight and obesity in adolescents. 54.6% of the subjects were boys. Mean (SD) levels of vitamin D and PTH were 18.25 (9.26) ng/mL and 45.39 (28.23) ng/L respectively. The prevalence of vitamin D deficiency and insufficiency in the current study was 54.6% and 25.9% respectively. However, PTH levels were high only in 24.2% of subjects (> 65 ng/L). There was an inverse but non-significant correlation between vitamin D and PTH. The association was same after adjusting for age, gender and weight. Our study highlights the high prevalence of vitamin D deficiency among overweight and obese adolescents in Telangana. Despite high vitamin D deficiency, very few had high PTH levels and the vitamin D–PTH axis may be altered in overweight and obese adolescents.