Blood pressure, growth and maturation from childhood through adolescence. Mixed longitudinal analyses of the Philadelphia Blood Pressure Project.

Abstract

This paper presents data on the extent to which blood pressure (BP) and growth status at 7 years of age are associated with BP, growth, and maturity status during adolescence. Two samples of black adolescents, namely, a representative sample (n = 562) stratified by sex and age (11 to 15 years) and a sample (n = 256) with supine BP over one standard deviation above the mean at 7 years of age (High BP7), were selected from the Philadelphia Collaborative Perinatal Project (CPP) population and followed longitudinally for 3 years. When the subjects reached adolescence we again measured supine blood pressure, height, weight, and skeletal maturity. Analyses of the data collected at 7 years of age by the CPP indicated that weight and height are highly significantly associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) respectively. Accordingly, the SBP, DBP, weights, and heights of the representative sample at age 7 were divided into percentile groupings (< 15%, 15%-85%, > 85%). Using mixed longitudinal analyses during adolescence, we found that mean SBP tracked in males through age 15 and in females through age 13 based on the percentile groupings of SBP, height, and weight. Moreover, the weight percentile groupings provided the best discrimination of SBP at these ages. Skeletal age also tracked throughout early adolescence using these percentile groupings of 7-year heights and weights. In females only, diastolic phase 4 (DBP4) during adolescence was significantly associated with 7-year height percentile groupings. In comparing the representative and the High BP7 samples at each chronological age for BP, height, weight, and skeletal age at adolescence (ages 12 to 17 years), it was found that the High BP7 sample was, on the average, taller and heavier at age 7 and throughout early adolescence. At age 17 in males, however, there were no significant differences in BP, growth, or maturity status. In females, SBP of the High BP7 sample remained significantly higher, and there was a tendency for them to remain heavier through age 17. Hence BP variation is so closely associated with growth and maturation that these factors must be taken into account when assessing BP in childhood and adolescence.