Effect of body mass index change on the development of diabetes mellitus

A high body mass index (BMI) is associated with the onset of diabetes mellitus (DM). However, evidence regarding the association between changes in BMI and DM onset is limited, and the effect of annual BMI (kg/m²/year) change on DM onset is unknown. Therefore, we assessed the effects of changes in BMI and annual BMI on DM onset. We enrolled 13,949 participants aged 21-81 years who underwent an annual health checkup at least twice between April 2003 and March 2021 and examined the effect of BMI change and annual BMI change on DM onset. In total, 462 individuals newly developed DM. Compared with a BMI change of -0.25-<0.25, univariate and multivariate analyses-adjusted for age, sex, BMI, systolic blood pressure, creatinine, total cholesterol, triglycerides, alanine aminotransferase, hemoglobin A1c, and family history of DM-showed that a BMI change <-2 was associated with a lower risk, while 2 ≤ BMI change < 4 and 4 ≤ BMI change were associated with a higher risk of DM onset. In contrast, compared with -0.05 ≤ BMI change per year < 0.05, univariate and multivariate analyses showed a significant association between DM onset and 0.3 ≤ BMI change per year. In the age-stratified analysis, these associations were significant among younger and middle-aged participants but not in older adults. In conclusion, changes in BMI affect DM onset. Therefore, clinicians can prevent DM onset by providing guidance based on BMI and focusing on a ≥2 increase in BMI and a ≥0.3 increase per year of BMI in young and middle-aged individuals.