Association between body weight time in target range and risk of type 2 diabetes in adults with obesity

Obesity is a major risk factor for type 2 diabetes, underscoring the need for effective weight management strategies for its prevention and control. We evaluated the association between body weight time in target range (TTR) and the risk of type 2 diabetes in adults with obesity. Using the 2010–2022 Korean National Health Insurance Service database, we included 248,367 adults with obesity with no history of diabetes. Body weight TTR was defined as the proportion of time maintaining a ≥ 3% reduction from baseline body weight. Participants were categorized into body weight TTR groups: 0%, > 0–50%, and > 50–100%. The primary outcome was the incidence of type 2 diabetes. Cox proportional hazards models were used. Over a median follow-up of 5.6 years, 46,737 participants (18.8%) developed type 2 diabetes. Individuals with body weight TTR > 0–50% and > 50–100% had significantly lower risk of type 2 diabetes compared with individuals with body weight TTR = 0%, with adjusted hazard ratios (aHR) of 0.86 (95% confidence interval [CI]: 0.84–0.88) and 0.66 (95% CI: 0.64–0.67), respectively. Each 10% increase in body weight TTR was significantly associated with a lower risk of type 2 diabetes (aHR: 0.95, 95% CI: 0.95–0.96). Five-year absolute risks declined across body weight TTR groups: 12.82%, 11.10%, and 8.62%. Among adults with obesity, a higher body weight TTR was significantly associated with a reduced risk of developing type 2 diabetes, highlighting the importance of sustained weight management in diabetes prevention.