Haemoglobin A1c is not a surrogate for glucose and insulin measures for investigating the early life and childhood determinants of insulin resistance and Type 2 diabetes in healthy children. An analysis from the Avon Longitudinal Study of Parents and Children (ALSPAC).

AIMS: Research into early life and childhood determinants of insulin resistance and Type 2 diabetes are complicated by requirements for fasting blood samples and glucose tolerance tests. We investigated haemoglobin A(1c) (HbA(1c)), a marker of glycaemia measured in non-fasting blood, as an alternative. METHODS: HbA(1c) was measured in 1645 children aged 9-11 years without diabetes from the Avon Longitudinal Study of Parents and Children. Thirty-nine children had two HbA(1c) measurements. Data on parental, child and potential confounding factors were collected prospectively from questionnaires, medical records and direct examination. Data from a shortened 30-min oral glucose tolerance test were available for 431 children at age 8 years. Body composition was measured by dual-energy X-ray absorptiometry. RESULTS: Mean (sd) HbA(1c) was 4.91(0.29)%. HbA(1c) increased with age and was higher in boys compared with girls, non-white compared with white children, and in children with anaemia. Mean difference between repeated HbA(1c) measurements was 0.01%. HbA(1c) was weakly positively associated with fasting glucose (beta = 0.066%/mmol/l, P = 0.05), but was not associated with 30-min glucose, fasting or 30-min insulin, or homeostasis model assessment-insulin resistance. HbA(1c) was weakly inversely associated with weight sd score (beta =-0.02%/unit, P = 0.004), body mass index sd score (beta = -0.02%/unit, P = 0.002), and total body fat (beta = -0.003%/kg, P = 0.06) and lean mass (beta = -0.011%/kg, P = 0.01), but was not associated with birthweight or breastfeeding. CONCLUSIONS: HbA(1c) is not a good marker of fasting or post-load glucose and insulin measures in healthy children, and is not a viable alternative to these measures for investigating the determinants of insulin resistance and Type 2 diabetes in children.

Does birth weight predict childhood diet in the Avon longitudinal study of parents and children?

STUDY OBJECTIVE: Low birth weight predicts cardiovascular disease in adulthood, and one possible explanation is that children with lower birth weight consume more fat than those born heavier. Therefore, the objective of this study was to investigate associations between birth weight and childhood diet, and in particular, to test the hypothesis that birth weight is inversely related to total and saturated fat intake. DESIGN: Prospective cohort study. SETTING: South west England. PARTICIPANTS: A subgroup of children enrolled in the Avon longitudinal study of parents and children, with data on birth weight and also diet at ages 8, 18, 43 months, and 7 years (1152, 998, 848, and 771 children respectively). MAIN RESULTS: Associations between birth weight and diet increased in strength from age 8 to 43 months, but had diminished by age 7 years. Fat, saturated fat, and protein intakes were inversely, and carbohydrate intake was positively associated with birth weight at 43 months of age, after adjusting for age, sex, and energy intake. After adjustment for other confounders, all associations were weakened, although there was still a suggestion of a relation with saturated fat (-0.48 (95% CI -0.97, 0.02) g/day per 500 g increase in birth weight. Similar patterns were seen in boys and girls separately, and when the sample was restricted to those with complete data at all ages. CONCLUSIONS: A small inverse association was found between birth weight and saturated fat intake in children at 43 months of age but this was not present at 7 years of age. This study therefore provides little evidence that birth weight modifies subsequent childhood diet.