Relation between birth weight and blood pressure: longitudinal study of infants and children.

OBJECTIVE To study the relation between birth weight and systolic blood pressure in infancy and early childhood. DESIGN Longitudinal study of infants from birth to 4 years of age. SETTING A middle class community in the Netherlands. PARTICIPANTS 476 Dutch infants born in 1980 to healthy women after uncomplicated pregnancies. MAIN OUTCOME MEASURES Systolic blood pressure and body weight measured at birth and at 3 months and 4 years of age; the relation between systolic blood pressure and birth weight as estimated by multiple regression models that include current weight and previous blood pressure and control for gestational age, length at birth, and sex. RESULTS Complete data were available on 392 infants. At 4 years of age the relation between blood pressure and birth weight appeared to be U shaped; low and high birthweight infants had raised blood pressure. Current weight and previous blood pressure were also positively associated with blood pressure at that age. Low birthweight infants (birth weight < 3100 g) had a greater gain in blood pressure and weight in early infancy. High birthweight infants (birth weight > or = 3700 g) had high blood pressure at birth, and weight and blood pressure tended to remain high thereafter. CONCLUSIONS Even among normal infants there seem to be subgroups defined by birth weight in which blood pressure is regulated differently. Future investigations are needed to examine the physiological basis of these differences. Studies of correlates of adult disease related to birth weight should investigate mechanisms related to increased risk separately in infants of low and high birth weight.