Endocrine Abstracts

Rationale: Patients with morbid obesity may have vitamin D deficiency and bariatric surgery may exacerbate it due to factors such as lack of dietary compliance, reduced intake, malabsorption, etc.

Objective: To study vitamin D deficiency prevalence in patients with morbid obesity before and after bariatric surgery and its relationship with other laboratory parameters.

Methods: A retrospective study of 88 morbidly obese patients before and 1 year after surgery (bypass or sleeve). We collected data about: age, sex, previous comorbidities, physical examination, impedance testing, and laboratory parameters (25-hydroxyvitamin D, iPTH, Ca, HbA1c, total cholesterol, LDL, HDL, triglycerides, uric acid, and leptin).

Results: The mean age of patients was 45.1±10.01 years, 78.4% women. Weight before and after surgery: 139.37±27.46 vs 89.5±16.89 (P<0.05). Mean weight lost in bypass and sleeve patients was: 51.8±18.1 vs 52.7±24.1 kg (P<0.05). One year after surgery there were significant decreases in HbA1c, TC, LDL, triglycerides, uric acid, leptin, and HDL increase. Mean serum 25-OH vitamin D pre and post bypass and sleeve was: presurgery 21.2±20.2 vs 17.7±8.8 ng/ml (NS) and postoperatory 27.0±2.06 vs 30.6±21.8 (NS). Mean PTH levels (bypass and sleeve): presurgery 51.8±15.6 vs 67.1±47.1 (NS) and postsurgery 53.9±28.6 vs 41.1±10.2 (NS). Percentage of deficiency (minor than 20 ng/ml) for by pass (pre and postsurgery) was: 41.9 vs 32.3% (P<0.05) and for sleeve 43.5 vs 26.1% (P<0.05). Hyperparathyroidism prevalence pre and postsurgery was: bypass 66.2 vs 64.6% (NS) and sleeve 50 vs 27.3% (NS). Mean PTH decrease in by pass and sleeve was: 1.8±28.1 vs 29.1 ng/ml (P<0.05) and vitamin D increase 4.3±21.4 vs 9.6±14.1 (NS). Vitamin D levels negatively correlated with preoperative age and body fat percentage. Vitamin D levels postsurgery correlated negatively with age. Mean postsurgery vitamin D levels in patients with BMI major and minor than 30 were: 23.97±16.2 vs 40.5±32.3 ng/ml respectively (P 0.05). Mean postsurgery vitamin D increase correlated with 1 year BMI (r: −0.45; P 0.05).

Conclusions: Patients with morbid obesity have vitamin D deficiency in high percentage of cases preoperatively, which should lead us to measure 25-OH vitamin D levels routinely. After the surgical procedure, despite systematic supplementation, patients maintain a high percentage of vitamin D deficiency and elevated iPTH.