Changes in the prevalence of overweight and obesity and their risk factors in Spain, 1987-1997.

BACKGROUND The aim of this study was to examine the relationship of the changes in the prevalence of overweight and obesity with the changes in some of their risk factors in Spain from 1987 to 1997. METHODS Data were obtained from three interview-based health surveys, covering representative samples of the noninstitutionalized Spanish population aged 16 years and over and undertaken in 1987 (n = 17,434), 1995 (n = 4,736), and 1997 (n = 4,678). To compensate for the different sample sizes, the 1995 and 1997 surveys were combined. Risk factors for obesity and overweight considered in this study were age, educational level, physical activity at work, physical activity during leisure time, tobacco use, alcohol consumption, and civil status. Data analysis was performed with logistic regression. RESULTS The prevalence of overweight and obesity (body mass index >or= 25 kg/m(2)) rose from 35.6% in 1987 to 40.9% in 1995/1997 among women and from 47.1 to 56.2% among men. In the period 1987-1995/1997, the proportion of persons with secondary or university education increased by 11.3% in women and 10.8% in men. Similarly, the prevalence of intense or regular leisure-time physical activity increased by 5.7 and 6.2% in women and men, respectively. The remaining risk factors for overweight and obesity registered no substantial change in prevalence over the study period. The prevalence of overweight and obesity expected in 1995/1997, had educational level and leisure-time physical activity been the same as in 1987, is higher than the observed figures; for educational level, expected figures are 7.3 and 1.4% higher than those observed among women and men, respectively, while for leisure-time physical activity corresponding values are 2.8 and 1.6%. CONCLUSIONS The rise in the prevalence of overweight and obesity in Spain from 1987 to 1997 may have been attenuated by an increase in leisure-time physical activity and by an improvement in educational level, particularly among women. The contribution to overweight and obesity trends attributable to physical activity at work or to tobacco and alcohol consumption appears to be small or null.