Objective: To assess the role of weight cycling independent of BMI and weight change in predicting the risk of developing type 2 diabetes.
Research methods and procedures: A six-year follow-up of 46,634 young and middle-aged women in the Nurses' Health Study II was conducted. Women who had intentionally lost > or = 20 lbs at least three times between 1989 and 1993 were classified as severe weight cyclers. Women who had intentionally lost > or = 10 lbs at least three times were classified as mild weight cyclers. The outcome was physician-diagnosed type 2 diabetes.
Results: Between 1989 and 1993, approximately 20% of the women were mild weight cyclers, and 1.6% were severe weight cyclers. BMI in 1993 was positively associated with weight-cycling status (p < 0.001). During 6 years of follow-up (1993 to 1999), 418 incident cases of type 2 diabetes were documented. BMI in 1993 had a strong association with the risk of developing diabetes. Compared with women with a BMI between 17 and 22 kg/m(2), those with a BMI between 25 and 29.9 kg/m(2) were approximately seven times more likely to develop diabetes, and those with a BMI > or = 35 kg/m(2) were 63 times more likely to be diagnosed with type 2 diabetes. After adjustment for BMI, neither mild (relative risk = 1.11, 95% confidence interval, 0.89 to 1.37) nor severe (relative risk = 1.39, 95% confidence interval, 0.90 to 2.13) weight cycling predicted risk of diabetes.
Discussion: Weight cycling was strongly associated with BMI, but it was not independently predictive of developing type 2 diabetes.