Offspring birth weight, gestational age and maternal characteristics in relation to glucose status at age 53 years: evidence from a national birth cohort

AIMS We investigated pathways linking offspring birth weight to maternal diabetes risk in later life by taking into account a range of prospective early-life and adult maternal factors. METHODS In a national birth cohort study, we examined the relationship between offspring birth weight and maternal glycated haemoglobin (HbA1c) at age 53 years in 581 mothers who had a first birth between age 19 and 25 years, and had data on potential confounders or mediators. RESULTS Mean age at first birth was 21.5 years. After adjustment for maternal body mass index (BMI), mean percentage change in maternal HbA1c per kilogram increase in offspring birth weight was -1.8%[95% confidence interval (CI) -3.5, -0.1; P = 0.03]. This relationship was mostly accounted for by gestational age that was inversely related to maternal HbA1c (-0.9%; 95% CI -1.5, -0.4; P = 0.001). Other risk factors for high HbA1c were smoking and high BMI at 53 years. There was a significant interaction between offspring birth weight and maternal childhood social class (P = 0.01). Mothers from a manual background with higher birth weight offspring had lower HbA1c (BMI adjusted: -3.1%; 95% CI -5.0, -1.1); this was not observed for mothers from a non-manual background (BMI adjusted: 1.9%; 95% CI -1.3, 5.0). CONCLUSIONS Short gestational age and low offspring birth weight may be part of a pathway linking impaired early maternal growth to diabetes risk in later life. A second possible pathway linking higher offspring birth weight to later maternal glucose status was also identified. These potential pathways require further investigation in cohorts with a wider maternal age range so that the early targeting of public health initiatives can be assessed.