Influence of Age on Associations Between Childhood Risk Factors and Carotid Intima-Media Thickness in Adulthood

BACKGROUND: Atherosclerosis has its roots in childhood. Therefore, defining the age when childhood risk exposure begins to relate to adult atherosclerosis may have implications for pediatric cardiovascular disease prevention and provide insights about the early determinants of atherosclerosis development. The aim of this study was to investigate the influence of age on the associations between childhood risk factors and carotid artery intima-media thickness, a marker of subclinical atherosclerosis. METHODS AND RESULTS: We used data for 4380 members of 4 prospective cohorts-Cardiovascular Risk in Young Finns Study (Finland), Childhood Determinants of Adult Health study (Australia), Bogalusa Heart Study (United States), and Muscatine Study (United States)-that have collected cardiovascular risk factor data from childhood (age 3 to 18 years) and performed intima-media thickness measurements in adulthood (age 20 to 45 years). The number of childhood risk factors (high highest quintile total cholesterol, triglycerides, blood pressure, and body mass index) was predictive of elevated intima-media thickness (highest decile) on the basis of risk factors measured at age 9 years (odds ratio 95% confidence interval 1.37 1.16 to 1.61, P=0.0003), 12 years (1.48 1.28 to 1.72, P<0.0001), 15 years (1.56 1.36 to 1.78, P<0.0001), and 18 years (1.57 1.31 to 1.87, P<0.0001). The associations with risk factors measured at age 3 years (1.17 0.80 to 1.71, P=0.42) and 6 years (1.20 0.96 to 1.51, P=0.13) were weaker and nonsignificant. CONCLUSIONS: Our analyses from 4 longitudinal cohorts showed that the strength of the associations between childhood risk factors and carotid intima-media thickness is dependent on childhood age. On the basis of these data, risk factor measurements obtained at or after 9 years of age are predictive of subclinical atherosclerosis in adulthood.