Relationship between birthweight and blood pressure in childhood

Studies have shown an inverse relationship between birthweight and blood pr essure in later life. The objective of this study is to analyze the relatio nship between birthweight and blood pressure in childhood in a North Americ an-based population. Data on 2,958 births with follow-up at 7 years of age from the Providence, RI, cohort of the Collaborative Perinatal Project of t he National Institute of Neurological Diseases and Stroke were retrospectiv ely analyzed using univariate and multivariate analytic methods. Bivariate analysis of the total cohort showed a direct relationship between follow-up weight at age 7 years and birthweight (r = 0.24; P < 0.001) and follow-up weight with systolic (SBP) and diastolic blood pressure (DBP; r = 0.33; P < 0.001 and r = 0.22; P < 0.001, respectively). On multivariate analysis, fo llow-up weight and height were the strongest predictors of SEP and DBP. The re was also a significant inverse relationship between birthweight and SBP. A cohort of term infants (n = 2,561) was subdivided into birthweight-for-g estational-age groupings to further evaluate the effects of birthweight on blood pressure, Small-for-gestational-age (SGA) infants were markedly small er at age 7 years than those large-for-gestational-age (LGA; 21 +/- 4 kg v 26 +/- 4 kg; P < 0.01). Despite the direct association between follow-up we ight and blood pressure, the mean blood pressure did not differ between SGA (103/58 mm Hg) and LGA patients (103/59 mm Hg). To assess whether birthweig ht was an independent predictor of blood pressure, blood pressures were pre dicted using linear regression equations. For every 1-kg decrease in birthw eight in term infants, SBP at 7 years increased by 1.3 mm Hg and DBP by 0.6 mm Hg. In conclusion, controlling for weight and height in term infants at 7 years of age has an inverse linear effect on blood pressure. This sugges ts that birthweight in relation to gestation may be a contributor to the mu ltifactorial cause of essential hypertension. (C) 1999 by the National Kidn ey Foundation Inc.