Metabolic syndrome severity and stroke risk: a longitudinal analysis in middle-aged and older chinese adults

Metabolic syndrome (MetS) contributes to cerebrovascular disease in older adults. Traditional binary diagnostic criteria may not fully capture metabolic dysfunction or its impact on stroke risk.

This study explores the relationship between MetS severity and stroke risk.

Data were derived from the China Health and Retirement Longitudinal Study (2011-2018). MetS severity was quantified using a validated scoring algorithm, and a cumulative severity score was calculated as the average of MetS scores at waves 1 and 3, weighted by the interval between waves. Cox proportional hazards models evaluated the relationship between baseline MetS severity and stroke events, while logistic regression assessed cumulative score in relation to incident stroke occurring after wave 3. Restricted cubic spline (RCS) functions were applied to explore nonlinear associations. Subgroup and interaction analyses were performed, and sensitivity analyses excluded participants receiving metabolic-related medications or with stroke occurring within two years prior to follow-up.

During a median follow-up of 7 years, 459 stroke cases were documented (7.04%). Each interquartile increase in baseline MetS score was associated with a 33.4% higher stroke risk (HR = 1.334; 95% CI 1.239-1.436). Stroke risk increased significantly across quartiles (P for trend < 0.0001), with the highest quartile exhibiting nearly a threefold greater risk compared with the lowest (HR = 2.923; 95% CI 2.208-3.871). Cumulative MetS score was also positively associated with stroke (OR = 1.034; 95% CI 1.025-1.043), with the highest quartile showing significantly elevated odds (OR = 1.069; 95% CI 1.049-1.092). RCS analyses demonstrated significant nonlinear associations between baseline and cumulative MetS scores and stroke risk in the overall population, whereas linear associations were observed in stratified analyses according to MetS status. Additional analyses assessing changes in MetS score between waves 1 and 3 showed no significant association with stroke risk.

Greater MetS severity is independently associated with increased stroke risk among middle-aged and older Chinese adults. These findings highlight the need for continuous surveillance of MetS severity and timely intervention to mitigate stroke burden in aging populations.