Trajectories of body mass index before the diagnosis of type 2 diabetes in a cohort of Taiwanese adults

Background: Although the prevalence of overweight/obesity is lower in Asian countries, the risk of type 2 diabetes (T2DM) is disproportionally higher. We identified and characterized the trajectory patterns of body mass index (BMI) before the onset of T2DM in a Taiwanese population. Methods: Using the Taiwan MJ cohort study, we sampled the health examination data of 22,934 participants, including 7618 cases of T2DM and 15,316 controls. We used latent class trajectory analysis to identify distinct groups of pre-disease BMI trajectory. To compare the trajectories of cardiometabolic risk factors among different groups, we used linear mixed-effects models. Results: These 22,934 participants included 13,074 men (57%) and 9860 women (43%) who were on average followed for 9.0 years. We identified three distinct pre-disease BMI trajectories in cases: “stable overweight” (n = 7016, 92.1%), “weight gain” (n = 333, 4.4%) and “obesity” (n = 269, 3.5%). The “stable overweight” group had a mean BMI of 24.6 kg/m² at 15 years prior to diagnosis, had a 1.2 unit increase during follow-up, and had a mean BMI of 25.8 kg/m² at the time of diagnosis. The “weight gain” group had the most increasing trends in blood pressure/low-density lipoprotein cholesterol over time. Conclusion: The BMI trajectory patterns among individuals who later developed diabetes in Taiwan seemed comparable to that of Western populations, but our population developed T2DM at a much lower BMI. Given that most cases belong to the “stable overweight” group, we also support using a population-based strategy for diabetes prevention instead of focusing on the high risk individuals.