ABSTRACT
BACKGROUND: Pacific adults and children have very high rates of obesity. OBJECTIVE: Body size at birth, 2- and 4 years for the whole cohort, compliant (not smoking and breastfed) and non-compliant children was compared to the 2006 World Health Organization (WHO) growth standard using z-scores. DESIGN: Longitudinal data (n=659) from the 2000 Pacific Island family birth cohort study of weight at birth and weight and height at 2- and 4 years was analysed. RESULTS: At birth the average child was 3.673+/-0.501 kg; z-score 0.605 units higher (P<0.000001) than the WHO standard. At 2- and 4 years, average z-scores for weight and body mass index (BMI) were significantly different from 0 (mean z-scores for weight +1.062 and +1.688, for BMI +1.701 and +1.969 respectively, P<0.000001). Mean height was significantly lower (P<0.000001) z-score=-0.232 at 2 years but higher (P<0.000001) at 4 years, z-score=+0.626. Over 4 years, the daily weight gain was 11.2 g day(-1) compared with 8.9 g day(-1) for the WHO child. Compliant (n=287) compared to non-compliant (n=372) weighed less and were slightly shorter at 2- and 4 years measurement points. Non-compliant children categorized as non-smoking (n=229) weighed more than smoking mothers' (n=143) children at birth, 2- and 4 years. CONCLUSION: Pacific children are born heavy, over 4 years increase in weight is faster and between 2- and 4 years increase in height is faster than the reference breastfed child, independent of pre- and postnatal factors. Smoking decreases the rate of weight gain and children who are not breastfed gain weight faster. Interventions to limit weight gain need to start with the family before conception.
Subject(s)
Body Mass Index , Body Weight , Obesity/etiology , Age Factors , Body Height , Child, Preschool , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Male , Pacific Islands , Reference Standards , World Health OrganizationABSTRACT
OBJECTIVE: To compare percentage body fat (%BF) for a given body mass index (BMI) among New Zealand European, Maori and Pacific Island children. To develop prediction equations based on bioimpedance measurements for the estimation of fat-free mass (FFM) appropriate to children in these three ethnic groups. DESIGN: Cross-sectional study. Purposive sampling of schoolchildren aimed at recruiting three children of each sex and ethnicity for each year of age. Double cross-validation of FFM prediction equations developed by multiple regression. SETTING: Local schools in Auckland. SUBJECTS: Healthy European, Maori and Pacific Island children (n=172, 83 M, 89 F, mean age 9.4+/-2.8(s.d.), range 5-14 y). MEASUREMENTS: Height, weight, age, sex and ethnicity were recorded. FFM was derived from measurements of total body water by deuterium dilution and resistance and reactance were measured by bioimpedance analysis. RESULTS: For fixed BMI, the Maori and Pacific Island girls averaged 3.7% lower %BF than European girls. For boys a similar relation was not found since BMI did not significantly influence %BF of European boys (P=0.18). Based on bioimpedance measurements a single prediction equation was developed for all children: FFM (kg)=0.622 height (cm)(2)/resistance+0.234 weight (kg)+1.166, R(2)=0.96, s.e.e.=2.44 kg. Ethnicity, age and sex were not significant predictors. CONCLUSIONS: A robust equation for estimation of FFM in New Zealand European, Maori and Pacific Island children in the 5-14 y age range that is more suitable than BMI for the determination of body fatness in field studies has been developed.
