Abstract
The association between intrauterine growth restriction (IUGR) and cardiovascular disease (CVD) later in life might be confounded by familial factors. We conducted a bi-national register-based cohort study to assess associations of birthweight for gestational age (GA), a proxy for IUGR, and GA with CVD risk in early adulthood, before and after addressing familial factors via sibling comparison. We included 3,410,334 live non-malformed singleton births in Sweden (1973-1996) and Denmark (1978-1998). During a median follow-up of 10 years from age 18 onwards, 29,742 individuals developed incident CVD (hypertensive, ischemic heart, and cerebrovascular diseases). Compared with individuals born with appropriate birthweight for GA (AGA, 10th-90th percentiles) or full term (39-40 gestational weeks), individuals born severely small for GA (SGA, <3rd percentile) or preterm (22-36 weeks) were at increased risk of CVD [HRs (95% CIs): 1.38 (1.32-1.45) and 1 .31 (1.25-1.38), respectively]. The association was attenuated when comparing individuals born SGA with their AGA siblings (1.11, 0.99-1.25), but remained robust when comparing individuals born preterm with their term siblings (1.21, 1.07-1.37). Our findings suggest that both SGA and preterm birth are associated with CVD risk in early adulthood, with greater familial confounding noted for SGA.
