Abstract
BACKGROUND: Atherosclerosis develops across the life course, and variation in aortic intima-media thickness (IMT) is evident from infancy onward, although most early-life data are cross-sectional. We investigated whether abdominal aortic IMT at age 6 weeks is associated with vascular measures at 4 years and the relationship of prenatal and perinatal exposures with these measures in early childhood. METHODS AND RESULTS: We analyzed data from 518 participants with 6-week and 4-year vascular measures from the Barwon Infant Study. Aortic IMT was measured at 6 weeks (mean, 6.1±SD 1.5 weeks) and aortic and carotid IMT, carotid-femoral pulse wave velocity, and blood pressure at 4 years of age (4.3±0.3 years). Associations of early-life exposures-maternal enteric microbiome, smoking and low-density lipoprotein cholesterol during pregnancy, birth weight, and gestational age-were also investigated. In the primary model, 6-week aortic IMT (649±66 μm) was associated with small differences in 4-year carotid IMT (453±45 μm) (mean difference in carotid IMT per 100 μm higher 6-week aortic IMT=7.0 μm [95% CI, 0.7-13.3]; P=0.03), with no evidence for associations with 4-year aortic IMT, pulse wave velocity, or blood pressure. Higher birth weight was associated with greater 4-year aortic IMT, and maternal smoking with higher systolic blood pressure. CONCLUSIONS: Vascular measures do not show strong evidence of tracking between infancy and early childhood. Longitudinal studies with repeated assessment beyond age 4 years would inform optimal timing of early prevention and targets for primordial prevention.