Treatment of vitamin D depletion after Roux-en-Y gastric bypass: a randomized prospective clinical trial.

BACKGROUND: A high prevalence (60%) of vitamin D (VitD) depletion, defined as a serum 25-hydroxyvitamin D level of < or =20 ng/mL, is present in preoperative morbidly obese patients. Despite daily supplementation with 800 IU VitD and 1500 mg calcium after Roux-en-Y gastric bypass (RYGB), VitD depletion persists in almost one half (44%) of patients. However, the optimal management of VitD depletion after RYGB and the potential benefits of such treatment are currently unknown. METHODS: A total of 60 VitD-depleted morbidly obese women were randomly assigned to receive 50,000 IU of VitD weekly after RYGB (group 1; n = 30) or no additional VitD after RYGB (group 2; n = 30). All patients received a daily supplement of 800 IU VitD and 1500 mg calcium. The serum calcium, parathyroid hormone, 25-hydroxyvitamin D, bone-specific alkaline phosphatase, urinary N-telopeptide, and bone mineral density were measured preoperatively and 1 year after RYGB. Questionnaires were used to assess other potential sources of VitD, including sunlight exposure and ingestion of VitD-containing foods/liquids. RESULTS: At 1 year after RYGB, VitD depletion and mean 25-hydroxyvitamin D level had improved significantly in group 1 (14% and 37.8 ng/mL, respectively) compared with the values in group 2 (85% and 15.2 ng/mL, respectively; P <.001 for both). A significant 33% retardation in hip bone mineral density decline (P = .043) and a significantly greater resolution of hypertension was seen in group 1 (75% versus 32%; P = .029). No significant adverse effects were encountered from pharmacologic VitD therapy. CONCLUSION: The results of our study have shown that 50,000 IU of VitD weekly after RYGB safely corrects VitD depletion in most women, attenuates cortical bone loss, and improves resolution of hypertension.

Effect of gastric bypass surgery on vitamin D nutritional status.

BACKGROUND: We previously reported a 60% prevalence of vitamin D (VitD) depletion, defined as a 25-hydroxyvitamin D (25-OHD) level of < or =20 ng/mL, in morbidly obese patients preoperatively. We now report the effect of gastric bypass (GB) on the VitD nutritional status in these patients. METHODS: We prospectively studied 108 morbidly obese patients who had undergone GB. Routine postoperative supplementation consisted of 800 IU VitD and 1500 mg calcium daily. Serum calcium, parathyroid hormone, and 25-OHD were measured before and 1 year after GB. RESULTS: The mean patient age was 46 +/- 9 years, 93% were women, and 72% were white. Preoperatively and at 1 year postoperatively, the prevalence of VitD depletion and hyperparathyroidism (HPT) and the mean 25-OHD level was 53% and 44%, 47% and 39%, and 20 and 24 ng/mL, respectively. One year after GB, the percentage of excess weight loss was 67% and demonstrated significant correlations both positively with 25-OHD and inversely with parathyroid hormone. At both intervals, blacks had a greater incidence of VitD depletion than did whites, and, at 1 year after GB, HPT was more common in patients with VitD depletion (55% versus 26%, P = .002). CONCLUSION: With customary supplementation, VitD nutrition is improved after GB, but VitD depletion persists in almost one half of patients, and blacks are at a significantly greater risk than whites. HPT did not improve, and those with VitD depletion had a significantly greater rate of HPT. Additional prospective studies are needed to determine how to optimize VitD nutrition and avoid potential long-term skeletal complications after GB.

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

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