['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.', '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.', '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.'] Is haemoglobin A1c 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 )?