Birth weight and growth trajectory to six years in Pacific children

To identify the relationship of birth weight with increased body mass and fatness at age six in Pacific children.

In the Pacific Islands Families Study, 722 New Zealand Pacific children who were full-term singleton births to mothers without known diabetes were enrolled at birth and were measured at six years. Birth weight was recorded and height and weight measured at two, four and six years of age; body mass index (BMI) was calculated and age-specific standard deviation (SD) scores determined from the CDC 2000 growth charts. At four and six years body fat percentage (%BF) was measured by bioelectrical impedance analysis.

Boys were born heavier and grew faster than girls. At six years the international obesity task force rates of overweight and obesity were 31.1% and 29.2%, respectively, for boys and 32.4% and 24.7%, respectively, for girls. Divided by sex and birth weight into quartiles children born heavy were the heaviest at six years but for children born small their weight SD score accelerated across the mean. Weight SD score increased faster than height SD score; at six years average SD scores for weight and height were 1.40 and 0.87. At six years SD scores for %BF were not different among birth weight quartiles but girls had a higher body fat than boys. At six years there was no measurable effect on body weight of not smoking during pregnancy or breastfeeding.

The weight increase trajectory of these children is steep and tracks from birth. Obesity prevalence measured by BMI or %BF SD score is alarmingly high.