Effects of Native Vitamin D Supplementation on Vitamin D Status and Body Composition After Sleeve Gastrectomy: A Retrospective Study in Japanese Patients

Introduction: The effect of vitamin D status after bariatric surgery on postoperative skeletal muscle condition has not been adequately studied.

Methods: Clinical data from 83 patients (median age 44 years, BMI 40.4 kg/m) who underwent sleeve gastrectomy (SG) were collected from medical records and analyzed retrospectively. Of the 83 patients, 37 who received continuous guidance on native vitamin D3 supplementation from before to 12 months after surgery were defined as the vitamin D supplementation (VDS) group, and 46 patients who did not receive such guidance as the control group. Native vitamin D3 supplement was provided by a dietitian at preoperative and postoperative visits. The supplementation dose was prescribed at 3000 IU/day after SG.

Results: In VDS group, blood 25-hydroxyvitamin D (25OHD) level increased significantly from 18.5 at baseline to 29.7 ng/mL at 3 months after surgery and plateaued, while 25OHD level remained low in the control group. In the analysis that included both groups, change in 25OHD level from baseline to 12 months after surgery correlated significantly with mean vitamin D intake (r = 0.596, p < 0.001) and 12-month post-SG/baseline ratio of percent lower limb skeletal muscle mass (r = 0.469, p < 0.05). Multiple regression analysis identified change in 25OHD level and mean exercise time as significant factors independently associated with 12-month post-SG/baseline ratio of percent lower limb skeletal muscle mass.

Conclusion: Vitamin D3 supplementation after SG is useful for improving vitamin D status that may be associated with prevention of postoperative lower limb skeletal muscle mass loss.