Ieong K, Ardila-Gatas J, Yang J, et al. - This study was undertaken to investigate the effect of vitamin D and calcium levels on bone mineral density (BMD) after sleeve gastrectomy (SG). Between 2014 to 2016, researchers conducted a retrospective chart review to include patients who had undergone Roux-en-Y gastric bypass (RYGB) or SG at a single institution. They preoperatively collected serum 25-hydroxy vitamin D and calcium levels and at the time of bone densitometry scan. They further compared BMD and T-score changes at the femoral neck, femoral trochanter, total hip, and lumbar spine between RYGB and SG patients. This research enrolled a sum of 40 patients. After RYGB and SG, all individuals were found to have decreased BMD. In BMD change, surgery type was not a significant risk factor. A reduction in vitamin D and calcium levels were correlated with a decrease in BMD, despite vitamin D and calcium supplementation in all patients. In all bariatric patients, close follow-up and treatment of vitamin D and calcium levels are warranted.