Hypovitaminosis D and hyperparathyroidism: a 5-year postoperative follow-up of 30,458 gastric bypass and sleeve gastrectomy patients.

Previous studies alongside these results suggest that RYGB, more so than SG, may cause hypovitaminosis D and thereby hyperparathyroidism, which could lead to osteopenia. The threshold for 25-OH-D should be >75 nmol/L, and despite higher levels, current vitamin D supplementation may not be sufficient. Follow-up should include screening for hyperparathyroidism and hypovitaminosis D.