Health behavior changes after type 2 diabetes diagnosis: a 16-year longitudinal cohort study

Abstract

Aims: This study evaluated the 16-year trajectories of smoking, drinking, exercise, and obesity before and after a diabetes diagnosis using a large-scale community-based longitudinal cohort. Methods: We analyzed 5091 participants without diabetes at baseline from the Korean Genome and Epidemiology Study (2003–2018). Participants underwent biennial health examinations to assess lifestyle behaviors. Those developing diabetes during follow-up were classified as the diabetes group. Generalized estimating equations examined temporal trends, group differences, and group-by-time interactions. Results: Overall, significant reductions occurred in smoking (P < 0.001), drinking (P < 0.001), and obesity (P = 0.007), with an increase in exercise (P < 0.001) across the cohort. Notably, the diabetes group showed a significantly greater increase in exercise (group-by-time interaction, P = 0.035) and a more pronounced reduction in obesity (P < 0.001) compared to those without diabetes. No significant group-by-time interactions were found for smoking and drinking. Conclusions: A diabetes diagnosis was associated with favorable changes in physical activity and weight management, serving as a critical window of opportunity for lifestyle intervention. These findings highlight the period around diagnosis as a key window for interventions supporting sustained lifestyle change. Such evidence informs the development of timely, targeted behavioral interventions for new-onset diabetes. © 2026 Elsevier B.V.