Long-term trends in obesity among Austrian adults and its relation with the social gradient: 1973-2007

Background: The prevalence of obesity is steadily increasing. There is little empirical evidence for the development of obesity in Austria. Therefore, the present study investigated long-term trends in the prevalence of obesity across different age and educational groups in Austrian adults. Methods: Self-reported data were derived from five nationally representative cross-sectional interview surveys (n = 178 818) in the years 1973, 1983, 1991, 1999 and 2006-07 in private homes and long-term care facilities for Austrian adults aged 20-99 years. An adjustment of the self-reported BMI was performed. Obesity was defined as BMI epsilon 30 kg m(-2). Results: The age-adjusted prevalence of obesity was 11% during the study period (women: 11.3%, 95% CI 11.2-11.6; men: 9.9%, 95% CI 9.7-10.2). Obesity and a high mean BMI were most prevalent among subjects aged 55-74 years and among those with low educational status. The absolute change in obesity prevalence during the study period was significantly highest (P < 0.001) among women aged epsilon 75 years (3.0%), and among men aged 55-75 years (3.6%). Concerning educational level, the largest increase in obesity was seen in those with a low educational level (women: 4.1%, men: 2.6%; P < 0.001), whereas the aetiologic fraction was highest in middle-educated men. Relative inequalities for obesity showed a tendency to increase during the study period. Conclusion: Examining trends in subpopulations is important when planning accurate target group-specific prevention strategies. Therefore, in Austria targeted preventive measures should be designed according to age and educational level.