Background: The objective was to investigate whether and to what extent the association between socioeconomic status and obesity can be explained by lifestyle factors.
Methods: The relationship between socioeconomic status (SES) and obesity, and the role of lifestyle factors such as smoking, physical activity, heavy alcohol use, avoidance of dietary fat and propensity to eat fiber-rich food, was studied in a cross-sectional population-based study consisting of 6394 men and women aged 25-74 years in Värmland County in Sweden. Educational level was used for measuring SES. The contribution of the measured lifestyle factors was assessed using logistic regression models.
Results: 12% of men and 14% of women were obese. Subjects with high education were leaner than subjects with low education, except among elderly women (65-74 years). Although many lifestyle factors were related to obesity and SES in this study, only a part (18-29%) of the association between educational level and obesity could be explained by the measured lifestyle factors. Physical inactivity and heavy alcohol use were the main factors contributing to this association, whereas smoking and the measured dietary attitudes towards fat and fiber had little additional effect.
Conclusions: The findings of this study are consistent with the view that socioeconomic differences in obesity and its consequences can only partly be reduced by changes in lifestyle. Longitudinal studies, a more detailed investigation of the role of dietary factors and more studies including elderly subjects are, however, recommended to further elucidate the association between SES and obesity.