Cardiovascular–kidney–metabolic syndrome stages 0–3 and cognitive decline in Chinese adults: a longitudinal analysis from the China health and retirement longitudinal study

Cardiovascular–kidney–metabolic (CKM) syndrome is increasingly linked to cognitive impairment, yet its association with cognitive trajectories at early stages remains unclear in Chinese adults. We analyzed 6,982 adults (≥ 45 years) without baseline clinical cardiovascular disease from the China Health and Retirement Longitudinal Study. Participants were classified into early CKM stages (0–3). Cognitive trajectories (standardized z-scores) over 7 years were evaluated using linear mixed-effects models. Cox proportional hazards models assessed the risk of substantial cognitive decline (≥ 1 SD decrease from baseline). Individuals in stage 3 showed significantly lower baseline cognitive scores than those in stage 0. All groups experienced cognitive decline during follow-up, but decline was faster in stage 3, whereas stages 1–2 showed trajectories similar to stage 0. Stage 3 was also associated with a higher, borderline significant risk of substantial cognitive decline after adjustment for demographic, behavioral, and clinical factors. CKM stage 3 was associated with poorer cognitive performance and accelerated cognitive decline. Early identification and comprehensive management of CKM syndrome may help preserve cognitive health.