Short‐Term Changes in General and Central Adiposity and Subsequent Cardiometabolic Risk in Japanese Adults Undergoing Routine Health Screening

Objective Annual health screening provides repeated measurements of body mass index (BMI) and waist‐based indices, but the implications of short‐term changes in general and central adiposity for cardiometabolic risk remain unclear. We examined whether 1‐year changes in BMI and waist‐to‐height ratio (WHtR) were associated with subsequent cardiometabolic outcomes and cardiovascular–kidney–metabolic (CKM) syndrome progression. Methods We analysed longitudinal health examination data from 144 394 Japanese employees aged 40–74 years between 2008 and 2023. One‐year changes in BMI and WHtR were calculated from two consecutive annual examinations, and outcomes were assessed during the following year. Outcomes included incident hypertension, dyslipidemia, hyperuricemia, diabetes, major adverse cardiovascular events, all‐cause mortality, and CKM stage progression. Pooled logistic regression with natural cubic splines was used to assess nonlinear associations, with analyses stratified by baseline BMI or WHtR quartiles. Results Increases in BMI and WHtR were consistently associated with higher risks of hypertension, dyslipidemia, hyperuricemia, and early CKM stage progression across baseline body size categories. For diabetes, increases in BMI and WHtR were associated with higher risk, whereas decreases were also associated with higher risk among leaner individuals. Associations with major adverse cardiovascular events were generally U‐shaped. BMI loss was associated with higher mortality odds, although estimates were imprecise and potentially affected by reverse causation. Conclusions One‐year changes in BMI and WHtR were associated with subsequent cardiometabolic risk and CKM stage progression. Anthropometric changes, particularly weight loss, may serve as signals for further assessment rather than causal determinants of risk.