Physical activity in leisure‐time and risk of cancer: 14‐year follow‐up of 28,000 Danish men and women.

Aim: The preventive effect of physical activity on risk of cancer in general remains controversial. This study aimed at assessment of the associations between leisure‐ time physical activity and incidence of cancer in the general population of adult men and women. Methods: 13,216 women and 18,718 men aged 20–93 years selected from the general population participated in a health examination including a questionnaire with information on physical activity, smoking, alcohol intake, postmenopausal hormones, and socioeconomic status. Incident cases of cancers where recorded during a follow‐up period of 14 years. The six most frequent cancer cases in both sexes were included in this analysis. Results: A highly significant inverse association was seen between vigorous physical activity in leisure time and cancer of the ovary, adjusted rate ratio being 0.33 (95% CI 0.16–0.67; p = 0.001) for the most physical active women. In men there was a highly significant increase for non‐melanoma skin cancer, with adjusted rate ratio of 1.72 (95% CI 1.23–2.40; p = 0.001), for the most active men and vigorous activity was associated with a non‐significant lower risk of colon cancer, the adjusted rate ratio being 0.72 (95% CI 0.47–1.11; p = 0.06). Conclusion: Generally, there were no, or only weakly, inverse associations between physical activity in leisure time and incidence of cancer, except for cancer of the ovary. [ABSTRACT FROM AUTHOR]