Do obesity and low levels of physical activity increase the risk for developing type 2 diabetes mellitus among women with prior gestational diabetes in rural China?

Moderate-to-vigorous intensity physical activity (MVPA) and obesity play important roles in the development of type 2 diabetes mellitus (T2DM) among women with prior gestational diabetes mellitus (GDM). Yet, how MVPA affects the risk of developing T2DM among women with prior GDM across the different categories of obesity indicators is unclear. This study aimed to describe the levels of postpartum abnormal glucose tolerance (AGT), obesity indicators (body mass index [BMI] and waist circumference [WC]), and MVPA and to explore the independent effect and joint effect of MVPA and obesity indicators (BMI and WC) on the risk for developing AGT among women with prior GDM in rural China. A total of 425 women with prior GDM were recruited from two county-level hospitals in Western and Eastern Hunan, China. Data were collected with self-reported measurements on sociodemographics and clinical factors as well as postpartum weight-related behaviors (physical activity and dietary intake). The 75-g oral glucose tolerance test, weight, height, and WC were measured on site. Binary logistic regression models and multiplitive interaction models were used to explore the independent and joint associations of BMI and MVPA as well as WC and MVPA on AGT, respectively. One-fifth (20.9%) of the sample women had AGT. The obesity indicators were significantly associated with an increased risk of postpartum AGT, but MVPA was not. In joint effect analyses, larger WC and insufficient MVPA were not significantly associated with increased risk of AGT compared with normal WC and sufficient MVPA (mutually adjusted odds ratio [OR], 1.43; 95% confidence interval [CI], 0.46-4.43; p > .05). In joint effect analyses of MVPA and BMI, the mutually adjusted OR for developing AGT in women who were obese and had insufficient MVPA was 4.49 (95% CI, 1.35-14.92; p < .05) compared with normal weight and sufficient MVPA. Adequate weight management and increased MVPA are warranted for Chinese women with prior GDM to prevent T2DM.