ASSOCIATION OF BLOOD-PRESSURE IN ADOLESCENCE WITH BIRTH-WEIGHT

Aims-To compare the blood pressure of very low birthweight infants wit h that of normal birthweight controls in adolescence. Methods-A cohort of all infants of birthweight less than or equal to 1500 g born to wo men resident in the county of Merseyside in 1980-1 was followed up at age 15 years with age, sex, and school matched controls. Growth indice s and blood pressures were measured under standard conditions. The smo king history of mothers and children and their status for several soci oeconomic variables were documented. In a matched pairs analysis systo lic and diastolic blood pressures were compared for cases and controls before and after adjusting for height, weight, and body mass index. R esults-There were 172 singleton 15 year old survivors of birthweight < 1500 g out of 40 321 live births to Merseyside residents in 1980-1. Of the 172 survivors, 128 (74%) who had no clinical disability and 11 (6 %) with a clinical disability but attending normal schools, were asses sed with individually matched age, sex, and school controls. Twenty th ree (13%) had a clinical disability and were attending special schools ; these were assessed without controls. Ten (6%) children refused or w ere unavailable for assessment. The systolic blood pressure was signif icantly higher in cases than in controls; the mean of the difference w as 3.2 mm Hg. The diastolic blood pressure was also higher in the case s, but the difference was not significant. The controls were significa ntly heavier (4.4 kg), taller (4.0 cm), with larger head circumference (1.5 cm) than the cases. The difference in body mass index was not si gnificant. Adjusting for height, weight, or body mass index increased the difference in systolic blood pressure between cases and controls. There were no significant differences in the socioeconomic variables, but what differences did exist favoured the controls. There was also a higher prevalence of smoking among the children and the mothers of th e cases than the controls. Conclusions-The study supports the hypothes is that in adolescents variation in systolic blood pressure has its or igins in fetal development. Some of the variation could be attributed to socioeconomic differences.