Factors Associated with High Weight Gain and Obesity Duration: The Norwegian Women and Cancer (NOWAC) Study

Aim: To identify factors associated with high weight gain and obesity duration in a representative sample of Norwegian women. Methods: 66,618 Norwegian women aged 34-70 years at baseline were included in the analysis. Baseline and follow-up questionnaires completed in 1991-2011 provided information on height, weight as well as sociodemographic, lifestyle and reproductive factors. We assessed the association with multivariable logistic regression. Results: Women gained on average 0.5 kg/year (95% CI 0.5-0.5 kg/year) during 6 years of follow-up, and 3.5% maintained in obesity during 13 years of follow-up. The factors with strongest association with high weight gain (>= 10 kg) were smoking cessation (cessation vs. no change, OR = 4.39, 95% CI 3.91-4.94) and decreased physical activity level (decrease vs. no change, OR = 2.40, 95% CI 2.21-2.61). Low physical activity level (high vs. low, OR = 0.17, 95% CI 0.14-0.20), higher than median age at menarche (over median vs. median or under median, OR = 0.36, 95% CI 0.31-0.41), and less than 10 years of education (>12 years vs. <10 years, OR = 0.44, 95% CI 0.37-0.51) were strongly associated with obesity duration. Conclusion: The modifiable factor with the strongest association with adverse weight development and potential for prevention was low or decreased physical activity level. (c) 2018 The Author(s) Published by S. Karger GmbH, Freiburg