Maternal obesity as a risk factor for early childhood type 1 diabetes: a nationwide, prospective, population-based case–control study
Maternal obesity as a risk factor for early childhood type 1 diabetes: a nationwide, prospective, population-based case-control study
Nina Lindell 0 1 2 3 4
Annelie Carlsson 0 1 2 3 4
Ann Josefsson 0 1 2 3 4
Ulf Samuelsson 0 1 2 3 4
Abbreviations IOM MBR SALAR 0 1 2 3 4
0 Department of Clinical and Experimental Medicine, Linköping University , Linköping , Sweden
1 Department of Obstetrics and Gynaecology, Linköping University , S-581 85 Linköping , Sweden
2 Nina Lindell
3 Division of Paediatrics, Linköping University , Linköping , Sweden
4 Department of Clinical Sciences, Lund University, Skåne University Hospital , Lund , Sweden
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;
Age at onset; BMI; Gestational weight gain; Obesity; Pregnancy; Type 1 diabetes
-
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.
SWEDIABKIDS
Introduction
Institute of Medicine Swedish Medical Birth Register Association of Local Authorities and Regions
Swedish National Quality Register for
Diabetes in Children
Type 1 diabetes is one of the most common chronic diseases in
children and young adults, and the incidence has increased
worldwide in recent decades [
1, 2
]. Since the 1980s, the
increase has been around 3% annually and the disease currently
affects about 500,000 children worldwide [3]. Second to
Finland, Sweden has the highest incidence of type 1 diabetes
in the world [
2
]. About 2% of children with diabetes in
Sweden are diagnosed with type 2 diabetes [
4
]. The aetiology
of type 1 diabetes is multifactorial, and both genetic and
environmental factors are thought to contribute [
5
]. The period
in which the rapid increase has occurred is too short to be
explained by genetic shifts, and is therefore believed to be
influenced by environmental factors [
6
].
In parallel with the increased incidence of type 1 diabetes, a
significant increase in obesity in the general population has
been observed worldwide. In the USA almost 35% of women
aged 20–39 are obese [
7
] and 48% of US women start their
pregnancy being overweight [
8
]. In Sweden the number of
pregnant obese women has doubled since the 1990s; in
2013, 25% of women were overweight and 13% were obese
in early pregnancy [
9
]. Some studies have shown a
relationship between high maternal pre-gestational BMI and high
gestational weight gain and subsequent risk of insulin
resistance, obesity and type 2 diabetes in the offspring [
10–12
].
Only a few studies, however, have looked at maternal BMI
and/or gestational weight gain and subsequent risk of type 1
diabetes in the offspring, and such studies have produced
conflicting results [
5, 13–18
].
The aim of this study was to further investigate the possible
effect of maternal BMI and gestational weight gain on the
subsequent risk of childhood type 1 diabetes in the offspring,
using data from the Swedish National Quality Register for
Diabetes in Children (SWEDIABKIDS) and the Swedish
Medical Birth Register (MBR).
Methods
SWEDIABKIDS is a national quality register (https://
swediabkids.ndr.nu/) [
19
] that includes approximately 99%
of children and adolescents with diabetes in Sweden. It was
introduced stepwise and rand (...truncated)