EFFECT OF LINEAR GROWTH RATE AND CHANGE IN BODY MASS INDEX IN CHILDHOOD AND ADOLESCENCE ON BLOOD PRESSURE IN AFRO-CARIBBEAN YOUTH: THE VULNERABLE WINDOWS COHORT STUDY

Abstract

ABSTRACTBackgroundFaster growth velocity during childhood may increase blood pressure (BP) in adults, but there are little data from African-origin populations. We evaluated the effect of postnatal linear growth (increase in height) and change in body mass index (BMI) from birth to adolescence on systolic and diastolic blood pressure (SBP and DBP) in Afro-Caribbean youth.MethodsWe used data from the Vulnerable Windows Birth Cohort Study in Jamaica. Children were followed from birth, with periodic anthropometric measurements. BP measurements started at age 1-year and every six months thereafter. Analyses used BP measurements (mmHg) from age 15-21 years. Linear growth and change in BMI measurements were calculated for: early infancy (0-6 months), late infancy (6 months - 2 years), early childhood (2-8 years), and later childhood (8-15 years). Conditional analyses were used to compute growth rates (as z-scores). Linear mixed models were used to estimate the effect of growth rates on BP.ResultsAnalyses included 365 individuals (162 males, 203 females) with mean age 16.7 years. In multivariable models, after adjustment for age, sex, birth length, gestational age and BMI at age 15 years, faster linear growth for early infancy (β=1.06, p=0.010) was significantly associated with higher SBP. For change in BMI, after adjustment for age, sex, gestational age, height and SES at birth, significant associations of higher SBP were seen for greater increase in BMI in late infancy (β=1.41, p=0.001), early childhood (β=1.22, p=0.001) and later childhood (β=0.74, p=0.035). Faster post-natal linear growth had no significant associations with DBP, but greater increase in BMI for each of the late infancy to late childhood periods was significantly associated with higher DBP. When both growth rates were modeled together, rate of change of BMI and faster linear growth in early infancy retained significance for SBP, but only change in BMI retained significance for DBP.ConclusionFaster linear growth and greater rate of increase in BMI were associated with higher SBP and DBP in Afro-Caribbean youth, but the BMI effect was stronger.