Birthweight, childhood growth, and blood pressure at 43 years in a British birth cohort

Background Low birthweight is associated with high blood pressure in later life, but it is unclear whether the association is confounded with or modified by maternal and socioeconomic factors or childhood growth. Methods A total of 3157 men and women from a British birth cohort study where the survey members have been followed up regularly since their birth in 1946 were included in analyses. The associations between birthweight, childhood growth and blood pressure at 43 years of age were assessed using multiple regression models. Results Systolic blood pressure (SBP) decreased by 2.3 mmHg (95% CI: 0.8, 3.5) for men and 1.8 mmHg (95% CI: 0.1, 3.5) for women per 1-kg increase in birthweight. The effect was stronger in first born or those born to younger mothers. There was no confounding with any maternal, socioeconomic, or childhood growth variable. SBP increased by 1.45 mmHg (95% CI: 0.11, 2.78) in women and 0.46 mmHg (95% CI: -0.70, 1.62) in men per standard deviation of body mass index (BMI) change between ages 7 and 15 years. Among women this effect was not completely accounted for by adult size and was independent of birthweight. Conclusions The determinants of birthweight, possibly related to maternal health during pregnancy, may impact on the relationship with SBP in middle life. The importance of tackling the increasing levels of childhood obesity seen in later cohorts is highlighted by the detrimental impact on SBP of large increases in BMI during adolescence.