Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery

Abstract Background Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. Methods We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. Results Mean patient age was 43 ± 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level ≤ 20 ng/mL, was found in 166 patients (60%). An elevated PTH level was found in 48% of the patients. A significant inverse correlation was found between serum 25-hydroxyvitamin D level and both body mass index ( r = .15; P = .012) and serum PTH level ( r = .45; P P Conclusions Before gastric bypass surgery, a majority of morbidly obese patients have vitamin D depletion and secondary hyperparathyroidism. Studies evaluating the effects of gastric bypass on vitamin D metabolism must consider preoperative vitamin D nutritional status. © 2006 American Society for Bariatric Surgery