The effect of cholecalciferol injection on serum 25 hydroxy vitamin D and parathyroid hormone in obese and none obese reproductive age women

Obese individuals are at high risk for developing endocrine and metabolic dysfunctions. Recent studies have linked obesity with alterations in the vitamin D endocrine system. Hypovitaminosis D can lead to hyperparathyroidism which can stimulate progressive depletion of bone minerals. The aim of this study was to investigate the effect of vitamin D injection on serum 25-hydroxy vitamin D and Parathyroid hormone levels in obese and non obese reproductive age women. This interventional study was performed on 86 healthy reproductive age women (17-50 years). 43 of these women had stage 1 and 2 obesity (BMI: 30-34.9 and 35-39.9 kg/m2 respectively) and 43 had normal weight (BMI: 18.5-24.9 kg/m2). Biochemical parameters were measured before and two weeks after injection of 600000 IU of vitamin D. Serum 25 hydroxy vitamin D, PTH and alkaline phosphatase were measured by Chemiluminescence Immuno Assay method, Enzyme Linked Immunosorbent Assay and Enzymatic method respectively. Serum calcium and phosphorous were measured colorimetrically. There was no significant difference between basal concentration of serum 25 hydroxy vitamin D in obese and none obese subjects, however, serum PTH concentration in obese group was significantly higher than none obese group (P<0.05). After vitamin D injection there was a significant increase in serum 25 hydroxy vitamin D, calcium and phosphorous and a significant decrease in serum PTH and alkaline phosphatase (P<0.05). Mean elevation in serum 25 hydroxy vitamin D among women with severe, moderate and mild vitamin D deficiency and women with vitamin D adequacy) was significantly different. (P<0.05). Considering strong modifier effect of vitamin D injection on vitamin D endocrine system, vitamin D supplementation can be a suitable method for treatment of these abnormalities.