The impact of preoperative vitamin administration on skeletal status following sleeve gastrectomy in young and middle-aged women: a randomized controlled trial

Background: The appropriate strategies to minimize skeletal deterioration following bariatric surgeries are inconclusive. This randomized controlled trial evaluated the effect of preoperative vitamin supplementation on bone mineral density (BMD) and biochemical parameters in females post-sleeve gastrectomy (SG).

Methods: Participants were randomized to a 2-month preoperative treatment with a multivitamin and vitamin D 4000 IU/d (intervention arm) or 1200 IU/d (control arm). Preoperative and 12-month postoperative follow-up evaluations included anthropometrics, biochemical parameters, and dual energy X-ray absorptiometry (DEXA).

Results: Sixty-two females (median age 29.7 years and median BMI 43.4 kg/m²) were recruited, 87% completed the 12-month follow-up. For the intervention and control arms, significant and similar reductions at 12-months post-surgery were observed in BMD of the hip (-6.8 ± 3.7% vs. -6.0 ± 3.6%; P = 0.646) and of the femoral neck (-7.1 ± 5.8% vs. -7.2 ± 5.5%; P = 0.973). For the intervention compared to the control arm, the 25 hydroxyvitamin D (25(OH)D) increment was greater after 2 months treatment, and vitamin D deficiency rates were lower at 3 and 6-months follow-up (P < 0.016). However, at 12-months postoperative, 25(OH)D values and vitamin D deficiency were comparable between the arms (P > 0.339). Predictors for BMD decline in the total hip were the percentage of excess weight-loss, age>50 years, and lower initial BMI (P ≤ 0.003).

Conclusions: SG was associated with a significant decline in BMD of the hip and femoral neck in young and middle-aged women, and was unaffected by preoperative vitamin D supplementation. Females who are peri-menopausal or with greater postoperative weight-loss should be particularly followed for BMD decline.