Low birth weight is associated with elevated systolic blood pressure in adolescence: a prospective study of a birth cohort of 149378 Swedish boys.

ABSTRACT

OBJECTIVES: To determine the association between birth weight and systolic blood pressure (SBP) in male adolescents at the age of 18 years. DESIGN: A prospective study by means of a register linkage between the Swedish Medical Birth Register and the national register for conscript testing before military service. METHODS: From the birth registry we collected data on birth weight, gestational age, maternal age and parity for 149378 individuals. At conscript testing, subjects were given a physical examination, and weight, height, and mean blood pressure were recorded after 5-10 min rest. RESULTS: Mean+/-SD birth weight was 3543+/-551 g after a mean of 39.7+/-2.0 gestational weeks. Mean+/-SD blood pressure at the conscript testing was 128.8+/-10.9/65.2+/-10.6 mmHg. SBP, but not diastolic blood pressure, differed significantly (test for trend, P< 0.001) between birth weight strata (deciles), with a higher SBP in strata with lower birth weight. A difference in birth weight of 1000 g decreased SBP by 0.8 mmHg. This was most pronounced in subjects with a rapid growth development (n = 1057), coming from the lowest decile of birth weight and reaching to the highest decile of body mass index, in a very consistent manner. The odds ratio for being in the top decile of SBP was 1.55 (95% confidence interval 1.32-1.81) for this growth 'catch-up' group compared with the rest of the cohort. CONCLUSIONS: Birth weight was inversely associated with SBP in a large cohort of young men in their late teens. This supports the notion of a programming effect of fetal growth retardation in utero on haemodynamic regulation in early adult life.