Transition to overweight or obesity among women of reproductive age

Background: Nearly two thirds of reproductive-aged women in the United States are currently overweight or obese, placing them at elevated risk for adverse health outcomes. This study identifies factors associated with transition in body mass index (BMI) category to overweight or obesity status over a 2-year period among women of reproductive age. Methods: Data were collected in the Central Pennsylvania Women's Health Study (CePAWHS), a longitudinal cohort study of reproductive-aged women. Participants were 689 women with normal or overweight BMI at baseline who were not pregnant at either baseline or 2-year follow-up. Separate multiple logistic regression analyses were estimated to model adverse change in weight category for women who were normal weight at baseline and to model transition to obesity among women who were overweight at baseline. Results: Among women of normal weight at baseline, 18% became overweight or obese by follow-up; 25% of women overweight at baseline became obese. In multiple regression analyses, low physical activity at baseline was significantly associated with a 2-fold elevation in the odds of transitioning from normal BMI to overweight/obesity (odds ratio [OR] 2.11, 95% confidence interval [CI] 1.06-4.20), as was having an interim live birth (OR 2.75, 95%CI 1.27-5.95). In contrast, demographics (lower education, younger age) were the only significant predictors of transition from overweight to obesity. Conclusions: Meeting physical activity guidelines should be encouraged among normal weight women of reproductive age as well as those who are overweight or obese, as low physical activity is a risk for transitioning from normal to overweight status. Younger overweight women are particularly at risk for transition to obesity.