Health disparities between Aboriginal and non-Aboriginal Australians have been attributed to chronic disease, with obesity and diabetes significant contributors.
Obesity in pregnancy is associated with increased risk of gestational diabetes (GDM), hypertensive disorders and high infant birthweight. High birthweights increases the risk of infants developing childhood obesity and subsequently adult-onset chronic disease.
Ethnicity is linked with differences in insulin sensitivity. Studies of Aboriginal female body types have found preferential central fat deposition relative to their overall weight. Body mass index (BMI) is thought to underestimate obesity in Aboriginal women.
To determine whether Aboriginal pregnant women have higher rates of obesity and GDM than non-Aboriginal pregnant women, and whether Aboriginal women a have higher incidence of GDM at lower BMIs.
Included in this study are 229 Aboriginal and 37538 non-Aboriginal pregnant women who gave birth at Royal Women’s Hospital between 1st January 2010 and 1st June 2015. Aboriginal status was determined by the mother identifying herself and her baby as Aboriginal or Torres Strait Islander. Obesity levels were compared using an independent-samples t-test and incidence of GDM with an odds ratio.
There was a significant difference in BMI scores for Aboriginal women (mean=27.65, SD 7.24) and non-Aboriginal women (mean=25.00, SD 5.48); t=5.11, p-value <0.01.
Aboriginal women were 1.6 times more likely to be diagnosed with GDM during pregnancy than non-Aboriginal women (9.1% vs 6.1%; p-value 0.05). There was no significant difference in the percentage of Aboriginal women being diagnosed with GDM at BMI <25 (2.6% vs 4.4%, OR 0.59, p-value 0.46) or BMI 25-29 (8.9% vs 6.6%, OR 1.38, p-value 0.5) compared to non-Aboriginal women.
Aboriginal women were found to suffer higher rates of obesity and GDM during pregnancy than non-Aboriginal women. Ethnicity did not affect rates of GDM found in normal weight and overweight women.