Continuous metabolic syndrome score and cardiometabolic multimorbidity risk in three nationwide cohorts.

To investigate the prospective association between the continuous metabolic syndrome score (cMetS) and incident cardiometabolic multimorbidity (CMM) across diverse populations. This prospective multicohort study included 7,114 participants from China (CHARLS), 3,400 from the United States (HRS), and 7,380 from the United Kingdom (ELSA), all aged ≥ 45 years and free of CMM at baseline. cMetS was derived from waist circumference, triglycerides, HDL-C, mean arterial pressure, and fasting glucose. Associations were assessed using Cox models, restricted cubic splines, and pooled random-effects meta-analysis. Over a median follow-up of 7, 4, and 6 years in CHARLS, HRS, and ELSA, 574, 170, and 317 incident CMM cases were documented, respectively. After full adjustment, the highest (vs. lowest) cMetS tertile was associated with significantly increased CMM risk (HR = 4.27 in CHARLS, 1.77 in HRS, 1.54 in ELSA). The pooled HR per 1-SD increase in cMetS was 1.35 (95% CI 1.17-1.56). Dose-response relationships were nonlinear in CHARLS but linear in HRS and ELSA. Associations were robust in subgroup and sensitivity analyses. Higher cMetS is consistently associated with increased CMM risk among middle-aged and older adults in three nations, suggesting its potential value for risk stratification, pending further validation.