Maternal obesity as a risk factor for early childhood type 1 diabetes: a nationwide, prospective, population-based case–control study

Abstract

Aims/hypothesis Genetic and environmental factors are believed to cause type 1 diabetes. The aim of this study was to investigate the influence of maternal BMI and gestational weight gain on the subsequent risk of childhood type 1 diabetes. Methods Children in the Swedish National Quality Register for Diabetes in Children were matched with control children from the Swedish Medical Birth Register. Children were included whose mothers had data available on BMI in early pregnancy and gestational weight gain, giving a total of 16,179 individuals: 3231 children with type 1 diabetes and 12,948 control children. Results Mothers of children with type 1 diabetes were more likely to be obese (9% [n = 292/3231] vs 7.7% [n = 991/ 12,948]; p = 0.02) and/or have diabetes themselves (2.8% [n = 90/3231] vs 0.8% [n = 108/12,948]; p < 0.001) compared with mothers of control children. Gestational weight gain did not differ significantly between the two groups of mothers. In mothers without diabetes, maternal obesity was a significant risk factor for type 1 diabetes in the offspring (p = 0.04). A child had an increased risk of developing type 1 diabetes if the mother had been obese in early pregnancy (crude OR 1.20; 95% CI 1.05, 1.38; adjusted OR 1.18; 95% CI 1.02, 1.36). Among children with type 1 diabetes (n = 3231) there was a difference (p < 0.001) in age at onset in relation to the mother's BMI. Among children in the oldest age group (15-19 years), there were more mothers who had been underweight during pregnancy, while in the youngest age group (0-4 years) the pattern was reversed. Conclusions/interpretation Maternal obesity, in the absence of maternal diabetes, is a risk factor for type 1 diabetes in the offspring, and influences the age of onset of type 1 diabetes. This emphasises the importance of a normal maternal BMI to potentially decrease the incidence of type 1 diabetes.

The influence of maternal body mass index, maternal diabetes mellitus, and maternal smoking during pregnancy on the risk of childhood‐onset type 1 diabetes mellitus in the offspring: Systematic review and meta‐analysis of observational studies

“…A small number of articles (n = 7) were also excluded for various reasons, including studies that were restricted to the enrolment of participants with genetic susceptibility to type 1 diabetes (human leukocyte antigen [HLA]), studies in which the outcome was islet autoimmunity rather than T1DM, a study that only reported the risk of DM, a study in which the onset of T1DM was not reported, or one study that had overlap of the patient population with another included study . Finally, 21 articles were eligible for the final inclusion in the present meta‐analysis. Of these, 12 were case‐control studies, eight were cohort studies, and one was a cross sectional study .…”

“…Finally, 21 articles were eligible for the final inclusion in the present meta‐analysis. Of these, 12 were case‐control studies, eight were cohort studies, and one was a cross sectional study . The characteristics of the included studies are summarized in Tables S1 ‐ S3.…”

“…Six studies with 13 510 cases of childhood T1DM were included in the analysis of maternal BMI. These six studies were all eligible for the meta‐analyses of maternal underweight, maternal overweight, and maternal obesity in relation to childhood‐onset T1DM.…”

“…Fourteen studies with 19 744 cases of childhood T1DM were included in the analysis of maternal DM. Infants born to mothers with DM had a three times increased risk for T1DM compared with infants born to mothers without DM (RR 3.26, 95% CI, 2.84‐3.74; Figure A), and infants of mothers with T1DM appeared to be at the highest risk of developing T1DM during childhood (RR 4.46, 95% CI, 2.89‐6.89; Figure A).…”

“…It is generally accepted that smoking may have detrimental effects on health. Surprisingly, several studies reported an inverse association between maternal smoking during pregnancy and the risk of childhood‐onset T1DM; however, this controversial result was not replicated in all studies. Given these considerations, we aimed to summarize and synthesize the associations between maternal BMI, maternal DM, and maternal smoking during pregnancy and the risk of childhood‐onset T1DM in the offspring by performing a systematic review and meta‐analysis of observational studies.…”