Distribution and Cross-Sectional Age-Related Increases of Carotid Artery Intima-Media Thickness in Young Adults

BACKGROUND AND PURPOSE: Reference values and age-related changes of carotid intima-media thickness (CIMT) have not been described in a community-based sample of young asymptomatic adults. CIMT measurements from the Bogalusa Heart Study, a study of the natural history of atherosclerosis in young adults and children, were used to characterize age-, race-, and sex-specific CIMT distributions and yearly rates of change. METHODS: Age-, sex-, and race-specific CIMT percentile values and cross-sectional changes with age were estimated using B-mode carotid ultrasound images from 519 young adults (mean age 32 years, 61% female, 29% black). Nomograms of CIMT percentiles between the ages of 25 and 40 years are provided in 5-year increments. RESULTS: CIMT was thickest in the carotid bulb and increased linearly with age, most rapidly in the bulb. With age, composite CIMT increased most slowly in white females and most rapidly in white males. Sample size estimates projected that 268 to 462 subjects are needed to detect CIMT changes > or =0.010 mm/year. CONCLUSIONS: These estimated CIMT distributions and percentiles can serve as reference values for assessment of subclinical atherosclerosis in young adults. The observed age-related differences in CIMT can be used to plan epidemiological and clinical trials investigating atherosclerosis and anti-atherosclerotic interventions.