Physical activity at work and duodenal ulcer risk.

To determine whether the social class differences in duodenal ulcer frequency may be explained by differences in physical activity at work, the energy expenditure during work, smoking habits, and social class were compared in 76 recently diagnosed duodenal ulcer patients and in age and sex matched community controls. As anticipated, the relative risk of duodenal ulcer showed significant associations with smoking and social class. Social class and physical activity at work were associated with one another. After adjusting for age, sex, smoking, and social class, physically active work was still associated with duodenal ulcer, with relative risks for moderate and high activity compared with sedentary work being 1.3 (0.6-3.0) and 3.6 (1.3-7.8) respectively. Within each social class stratum, the relative risk of having a duodenal ulcer was greater in those with a high level of occupational activity than in those undertaking sedentary work.