The Association Between Composite Healthy Lifestyle Score and Type 2 Diabetes Risk in the Korean Population: The Korean Genome and Epidemiology Study

Background/Objectives: Modifiable lifestyle factors, particularly diet, are important for preventing type 2 diabetes (T2D); however, the evidence regarding this from prospective studies is limited in the Asian population. We therefore evaluated whether a diet-inclusive healthy lifestyle score (HLS) predicts incident T2D in a community-based cohort. Methods: We analyzed 7185 T2D-free adults from the KoGES Ansan–Ansung cohort, constructing the HLS (range: 0–5) based on five lifestyle factors: non-smoking, ≥30 min/day of moderate-to-vigorous physical activity, low-risk alcohol consumption (≤40 g/day for men; ≤20 g/day for women), BMI of 18.5–24.9 kg/m², and a healthy diet, defined as a healthy plant-based diet index within the top 40th percentile. Cox proportional hazards regression models were employed to examine the association between HLS and incident T2D risk. Results: During a median follow-up of 17.5 years, 1223 cases of T2D were identified. Compared to individuals with a score of 0 or 1, those with a score of 5 had a 56% lower risk of T2D after adjustment for potential confounders (HR: 0.44, 95% CI: 0.32–0.62), and these associations remained consistent across subgroups stratified by age, sex, family history of T2D, hypertension, and residential area. However, the association was stronger among non-users of anti-diabetic medication than among users. Conclusions: Adherence to a healthier lifestyle, as indicated by a higher HLS, was significantly associated with a reduced risk of developing T2D among Korean adults. These findings underscore the importance of promoting integrated healthy lifestyle behaviors to prevent T2D.