BMI trajectory and subsequent risk of type 2 diabetes among middle-aged women.

BACKGROUND AND AIMS: Little is known about how weight trajectories among women during menopausal transition and beyond may be related to risk of type 2 diabetes mellitus (T2DM). The aim of this study was to examine associations between body mass index (BMI) trajectories over 20 years, age of obesity onset, cumulative obese-years and incidence of T2DM among middle-aged women.

METHODS AND RESULTS: 12,302 women enrolled in the Australian Longitudinal Study on Women's Health (ALSWH) were surveyed in 1996 (Survey 1, age 45-50), 1998 and then every three years to 2016. Self-reported weight and height were collected for up to eight time points. Incident diabetes was assessed via validated self-report of physician-diagnosed diabetes. Growth mixture models were used to identify distinct BMI trajectories. A total of 1380 (11.2%) women newly developed T2DM over an average 16 years of follow-up. Seven distinct BMI trajectories were identified with differential risk of developing T2DM. Initial BMI was positively associated with T2DM risk. We also observed that risk of T2DM was positively associated with rapid weight increase, early age of obesity onset and greater obese-years.

CONCLUSION: Slowing down weight increases, delaying the onset of obesity, or reducing cumulative exposure to obesity may substantially lower the risk of developing T2DM.