Risk factors for secondary hyperparathyroidism after bariatric surgery: a comparison of 4 different operations and of vitamin D-receptor-polymorphism.

To determine the relative frequency of secondary hyperparathyroidism after 1 of 4 standard bariatric surgical procedures, with respect to vitamin D-receptor (VDR) Bsm1 genotype-polymorphism (VDRP). Included were 141 obese men and women [aged 44.6±10.4 years, body mass index (BMI) 44.4±5.4 kg/m 2 ], who had undergone either gastric banding (GB; n=39), laparoscopic sleeve-gastrectomy (LSG; n=31), Roux-en-Y-gastric-bypass (RYGB; n=43), or biliopancreatic-diversion with “duodenal switch” (BP-DS; n=28)]. They were tested for VDR-genotype (Bsm1), vitamin D, and serum-PTH-levels postoperatively. Analysis of Covariance revealed a treatment effect, showing statistically significantly higher PTH-levels after BP-DS than after GB (mean difference=32.14, p In a comparison of the 4 most frequently performed bariatric operations vitamin-D-receptor polymorphism (VDRP) had no influence on the development of postoperative secondary hyperparathyroidism (SHPT) and is not useful as a predictor. SHPT occurs most often after BP-DS. Operation type, gender, VDRP, preoperative BMI, and relative postoperative BMI-loss, however, only explain 24% of the variance in postoperative PTH levels. Other gastral or intestinal factors physiologically promoting calcium-turnover and PTH regulation are postulated.