Diabetes during pregnancy and birthweight trends among Aboriginal and non-Aboriginal people in the Northern Territory of Australia over 30 years

Matthew J L Hare; Federica Barzi; Jacqueline A Boyle; Steven Guthridge; Roland F Dyck; Elizabeth L M Barr; Gurmeet Singh; Henrik Falhammar; Vanya Webster; Jonathan E Shaw; Louise J Maple-Brown

doi:10.1016/j.lanwpc.2020.100005

Diabetes during pregnancy and birthweight trends among Aboriginal and non-Aboriginal people in the Northern Territory of Australia over 30 years

Lancet Reg Health West Pac. 2020 Jul 24:1:100005. doi: 10.1016/j.lanwpc.2020.100005. eCollection 2020 Aug.

Authors

Matthew J L Hare^{1

2}, Federica Barzi¹, Jacqueline A Boyle³, Steven Guthridge⁴, Roland F Dyck⁵, Elizabeth L M Barr^{1

6}, Gurmeet Singh^{7

8}, Henrik Falhammar^{1

2

9

10}, Vanya Webster¹¹, Jonathan E Shaw^{6

12}, Louise J Maple-Brown^{1

2}

Affiliations

¹ Wellbeing and Chronic Preventable Diseases Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
² Department of Endocrinology, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
³ Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia.
⁴ Centre for Child Development and Education, Menzies School of Health Research, Darwin, Northern Territory, Australia.
⁵ Department of Medicine, Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Canada.
⁶ Clinical Diabetes and Epidemiology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.
⁷ Child Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia.
⁸ Department of Paediatrics, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
⁹ Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
¹⁰ Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden.
¹¹ Indigenous Reference Group, Diabetes across the Lifecourse: Northern Australia Partnership, Menzies School of Health Research, Darwin, Northern Territory, Australia.
¹² Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.

Abstract

Background: Early-life risk factors, including maternal hyperglycaemia and birthweight, are thought to contribute to the high burden of cardiometabolic disease experienced by Indigenous populations. We examined rates of pre-existing diabetes in pregnancy, gestational diabetes mellitus (GDM) and extremes of birthweight over three decades in the Northern Territory (NT) of Australia.

Methods: We performed a retrospective cohort analysis of the NT Perinatal Data Collection from 1987 to 2016, including all births >20 weeks gestation, stratified by maternal Aboriginal identification. Key outcomes were annual rates of pre-existing diabetes, GDM, small-for-gestational-age, large-for-gestational-age, low birthweight (<2500 g), and high birthweight (>4000 g). Logistic regression was used to assess trends and interactions.

Findings: 109 349 babies were born to 64 877 mothers, 36% of whom identified as Aboriginal ethnicity. Among Aboriginal women, rates of GDM and pre-existing diabetes, respectively, were 3 · 4% and 0 · 6% in 1987 and rose to 13% and 5 · 7% in 2016 (both trends p<0 · 001). Among non-Aboriginal women, rates of GDM increased from 1 · 9% in 1987 to 11% in 2016 (p<0 · 001), while pre-existing diabetes was uncommon (≤0 · 7% throughout). Rates of small-for-gestational-age decreased, while rates of large-for-gestational-age and high birthweight increased in both groups (all trends p<0 · 001). Multivariable modelling suggests that hyperglycaemia was largely responsible for the growing rate of large-for-gestational-age births among Aboriginal women.

Interpretation: The burden of hyperglycaemia in pregnancy has grown substantially in the NT over three decades and is impacting birthweight trends. The prevalence of pre-gestational diabetes in Aboriginal women is among the highest in the world.

Funding: Diabetes Australia Research Program.