Importance of Age and Sex in Carotid Artery Plaque Detection and Cardiovascular Disease Risk.

Carotid artery plaque (CAP) is commonly encountered in clinical practice. Presence of CAP predicts future atherosclerotic cardiovascular disease (ASCVD) events; however, CAP prevalence increases with age, and it is unknown how age and sex affect the association of CAP presence and ASCVD risk. To describe CAP prevalence by age, sex, race, and ethnicity in a multiethnic population and to investigate whether the impact of CAP detection on relative ASCVD risk declines with age and differs by sex. This cohort study examines participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Adults aged 45 to 84 years who were free of clinical ASCVD at recruitment (2000-2002) were included, and follow-up for ASCVD events was conducted through December 2019. Data analysis was performed from July 2023 to April 2024. Presence of CAP. The primary outcome was ASCVD events (coronary heart disease events, stroke, and ASCVD death). Prevalence of CAP by age, sex, race, and ethnicity was calculated. Cox proportional hazards models with age interaction terms were used to investigate associations of CAP and incident ASCVD events across sexes. Among 6814 adults in the MESA cohort, 5689 participants had complete data and were included in this analysis. Among these 5689 participants, mean (SD) age was 62.0 (10.2) years, and 3002 participants (53%) were female. The cohort included 1551 Black participants (27%), 687 Chinese participants (12%), 1276 Hispanic participants (22%), and 2165 White participants (38%). In total, participants experienced 1043 ASCVD events over a median (IQR) period of 17.6 (10.5-18.4) years. Prevalence of CAP differed by age, sex, race, and ethnicity, ranging from 15% in Chinese women younger than 50 years to 95% in non-Hispanic White men aged 80 to 84 years. CAP independently predicted ASCVD events (hazard ratio, 1.38; 95% CI, 1.20-1.58; P < .001). The strength of this association was stronger among younger participants (≤60 years) vs older (>60 years) (P for interaction = .01), especially among women (P for interaction = .005) vs men (P for interaction = .66). CAP detection in younger individuals conferred higher relative ASCVD risk than in older participants, who had higher absolute risk regardless of CAP. CAP becomes very common with increasing age among individuals without clinical ASCVD, and the association of CAP with incident ASCVD events was strongest in younger ages, especially among women. These data can help guide ASCVD risk assessment in younger adults and provide perspective when CAP is detected on clinical imaging studies in older adults.