Differences in association between birth parameters and blood pressure in children from preschool to high school

We aimed to investigate the association between birth parameters with blood pressure (BP) among preschool- and school-aged children. Two separate childhood datasets were used: (1) 1295 children aged 3–6 years were examined during 2007–2009; and (2) 1741 and 2353 children aged 6 and 12 years, respectively, were examined during 2004–2006. Birth parameter data were obtained from parental records. BP was measured using standard protocols. Among 6-year-old children, each 1 kg decrease in birth weight was associated with a 1.33- and 1.20-mm Hg higher systolic and diastolic BP, respectively, after multivariable adjustment. In 6-year-old children, a decrease of 1 week in gestational age was independently associated with a 0.33- and 0.37-mm Hg higher systolic and diastolic BP, respectively. Six-year-old children in the low birth weight category (⩽2499 g) versus those in the normal/high birth weight category (⩾2500 g) had significantly higher systolic BP (P<0.0001). Girls in the low birth weight category versus those in the normal/high weight category had higher systolic BP (P=0.02). Significant associations were not observed among preschool-aged children and preadolescents. Birth weight and gestational age were strongly associated with BP among 6-year-old children, particularly girls, but not among preschoolers or preadolescents.