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

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-gestationalage, low birthweight (< 2500 g), and high birthweight (> 40 0 0 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-gestationalage 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.

Trends and burden of diabetes in pregnancy among Aboriginal and non-Aboriginal mothers in Western Australia, 1998–2015

“…Among Australian Aboriginal and Torres Strait Islander (the First Nations Peoples of Australia; the term ‘Aboriginal’ is respectfully used hereafter—see Terminology in the Methods section for further details) mothers, DIP is more prevalent and the rates of type 2 diabetes mellitus (T2DM) in pregnancy may be ten times higher compared with non-Aboriginal women [ 5 ]. The current PGDM rates among Aboriginal women in the Northern Territory of Australia are among the highest in the world [ 6 ]. The risk of GDM is 1.5 times higher in Aboriginal mothers [ 5 ].…”

“…There is also scarcity of evidence about the temporal contribution of DIP to population-wide adverse neonatal outcomes and the possible long-term effect of DIP on Aboriginal offspring. A recent study from Australia’s Northern Territory revealed that, over 30 years, the prevalence of PGDM increased ten-fold among Aboriginal mothers [ 6 ]. The study also found that DIP largely explained the increasing rates of LGA among Aboriginal women over three decades [ 6 ].…”

“…A recent study from Australia’s Northern Territory revealed that, over 30 years, the prevalence of PGDM increased ten-fold among Aboriginal mothers [ 6 ]. The study also found that DIP largely explained the increasing rates of LGA among Aboriginal women over three decades [ 6 ]. Evidence from other culturally distinct Aboriginal populations in other Australian states is lacking.…”

Incorporating Aboriginal women’s voices in improving care and reducing risk for women with diabetes in pregnancy - A phenomenological study

“…Rates of hyperglycaemia in pregnancydue to preexisting type 2 diabetes or gestational diabetes (GDM)are disproportionately higher among Indigenous women worldwide [1,2]. In the Australian context, Aboriginal women are 1.2 times more likely to have GDM and greater than 10 times more likely to have pre-existing type 2 diabetes than non-Indigenous women [3]. Recurrence of GDM is reported to occur in 30-84 % of subsequent pregnancies [4] and women with GDM have a sevenfold higher risk of developing type 2 diabetes compared to women without GDM [5].…”

The ongoing effect of diabetes during pregnancy and the impact on infants

“…In this issue of The Lancet Regional Health-Western Pacific , Hare and colleagues have reported on over three decades of data on hyperglycaemia (defined as pre-existing and gestational diabetes) during pregnancy and birthweight trends in a cohort of Aboriginal and non-Aboriginal women from the Northern Territory, Australia. [1] The authors report on the increase in rates over time in gestational diabetes (3.4% in 1987 to 13% in 2016) and pre-existing diabetes (0.6% in 1987 to 5.7% in 2016) in pregnant Aboriginal women. A similar increasing trend for gestational diabetes was also reported for non-Aboriginal women (1.9% in 1987 to 11% in 2016), with no change in pre-existing diabetes (≤0.7% throughout).…”