Background: Vitamin D deficiency is associated with obesity and type 2 diabetes mellitus (T2DM), although the use of circulating Vitamin D levels as a predictor of weight loss induced T2DM remission is unclear. Therefore, the aim of this study was to analyze whether pre-bariatric surgery vitamin D levels may predict T2DM outcomes 12 months post-SG.

Method: A cohort of 220 obese participants (74.5% female) with T2DM (Age: 50±9.5yr, BMI: 51.4±7Kg/m2; n=103) and without T2DM (Age: 46±9yr, BMI: 53.5±6.5Kg/m2; n=117) undergoing SG participated in an ethics approved study in a single bariatric centre in the UK. Patient anthropometric and biochemical data including vitamin D were collected at baseline and 12 months post-SG; no vitamin D supplementation at baseline was given.

Results: Baseline vitamin D levels inversely correlated with baseline BMI (P<0.001, r=-0.35). Age, pre-op weight loss and vitamin D levels were correlated with HbA1c 12 months post-SG (P<0.001, r=0.28, P<0.001, r=-0.25 and P<0.05, r=-0.19). Furthermore, baseline vitamin D levels predicted levels of HbA1c post-surgery following adjustment for pre-op weight loss and age. Within the T2DM group, those that achieved T2DM remission 12 months post-SG (49.5%; n=51) had a higher baseline vitamin D compared to those not in remission (43.5±23.8 vs. 33±19nmol/L; P<0.05), with no significant differences between the two groups in baseline BMI, hypertension, pre-op weight loss or excess weight loss (EWL). Interestingly, patients with higher pre-surgical Vitamin D levels also had significantly lower BMI (P<0.005) and higher % EWL (P<0.05) 12 months post-surgery.

Conclusion: Baseline Vitamin D levels appear to be an independent indicator for successful T2DM remission and weight loss, 12 months following SG. The use of baseline Vitamin D levels may help us predict those more likely to do well and prioritize post-surgery support to achieve success for all participant groups.


A. Aladel: None. M.K. Piya: None. S. Azharian: None. M. Christian: None. V. Menon: None. P.G. McTernan: None.

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