In an Aboriginal birth cohort, only child size and not birth size, predicts insulin and glucose concentrations in childhood

The objectives were to describe cross-sectional growth in 279 Australian Aboriginal children aged 8-14 years in order to test the hypothesis that birth size interacts with child size to predict glucose and insulin metabolism. Cross-sectional growth outcomes were described using standard deviation scores or z-scores for height for age (HAZ) and weight for age (WAZ) calculated from CDC 2000 reference values in Epi Info 2000. Interrelationships were examined using standard regression models with current height and weight and birth weight, ponderal index and birth weight below the 10th percentile for gestational age. All models were adjusted for gestational age, gender and chronological age. Growth outcomes were poor with negative mean z scores for height and weight. Children with a birth weight <10th percentile for gestational age were significantly smaller and lighter than those with a birth weight≥10th percentile for gestational age, indicating post-natal catch-up growth of small babies was unlikely. After adjustment for childhood size, there was no relationship between any birth measures and fasting glucose or insulin concentrations. Current child height and weight had positive relationships with both fasting insulin and glucose concentrations with a greater proportional change for insulin. For every increment of 1 cm in height or 1 kg in weight, insulin concentrations rose 2% whereas glucose increased by only 0.2%. In this indigenous Australian cohort with poor post-natal growth, only current child size is related to measures of glucose and insulin metabolism.