BackgroundObesity is a major independent risk factor for developing type 2 diabetes (T2D). ObjectivesOur goal in this study was to analyze the impact of laparoscopic sleeve gastrectomy in the risk reduction of developing T2D in middle-aged, severely obese nondiabetes patients. SettingUniversity Hospital, United States. MethodsWe retrospectively reviewed our prospectively collected database from 2010 to 2016. All severely obese patients between 45 and 64 years of age without diabetes at baseline that underwent sleeve gastrectomy were included in our study. The T2D risk score for predicting the incidence of diabetes was measured preoperatively and at 12 months postoperatively and was based on the Framingham Offspring Study that calculates an 8-year risk of developing T2D. ResultsOf the 1330 patients included in this study, 6.5% (n = 86) met the criteria for the T2D risk score calculation. The population was predominantly composed of females (68.9%; n = 59) with a mean age of 52.8 ± 5.3 years. Preoperative body mass index was 43.1 ± 6.9 kg/m2 with a percentage of estimated body mass index loss and percentages of total weight loss were 72.2 ± 26.3% and 26.39 ± 18.15%, respectively, with fasting plasma glucose of 103.3 ± 14.9 mg/dL. The preoperative risk for T2D was 13.9 ± 11.6%, with an absolute risk reduction 12 months after surgery of 10.3%, corresponding to a 74.2% relative risk reduction. When comparing between sexes, risk reduction in females was slightly better than in males; however, this was not statistically significant. At 12-month follow-up, all measured variables were significantly improved, except for diastolic blood pressure. ConclusionsLaparoscopic sleeve gastrectomy significantly decreases the risk of developing T2D in middle-aged severely obese patients. Prospective studies are needed to further understand these findings.