Abstract
STUDY OBJECTIVE: The purpose of this study was to investigate the relation between blood pressure at age 36, and birth weight and body mass index (BMI) in childhood, adolescence and adulthood. DESIGN: Prospective longitudinal survey over a period of 36 years in England, Scotland, and Wales. PARTICIPANTS: A nationally representative sample consisting of 3332 men and women born in one week in March 1946. Altogether 82% of these subjects had complete data for the present analysis. MAIN RESULTS: There was an inverse linear relation between birth weight and blood pressure at age 36. The relation between BMI and blood pressure at age 36 was initially inverse and became increasingly positive throughout life. Weight gain in childhood was positively associated with adult blood pressure, although less important than weight change in later life. The associations between blood pressure and birth weight, and blood pressure and adult BMI were independent, and together they accounted for no more than 4% of the variation in adult blood pressure. Both low birth weight (birth weight < or = 2.5kg) and high BMI at age 36 (BMI > 30kg/m2) were associated with hypertension (> 140/90mmHg), but the per cent population risk of hypertension attributable to low birth weight was less than 5%, and to high BMI less than 12%. CONCLUSIONS: Low birth weight and high BMI at age 36 were independently related to high blood pressure. A reduction in the percentage of low birthweight babies born in the fourth decade of this century would only have a negligible effect on the incidence of adult hypertension 30-40 years later.