Physical activity and stomach cancer risk: the influence of intensity and timing during the lifetime.

Physical inactivity is linked to risk for cancers of the colon, breast, lung and endometrium, but few data exist on this association with stomach cancer. We evaluated the association between recreational physical activity and incident stomach cancer in a case-control study. The data yielded odds ratios suggestive of approximately 20-40% reduced risk of stomach cancer when comparing more frequent (3+ times/week) to less frequent (<1/month) strenuous activities. The magnitudes of the associations for strenuous physical activities were consistent across the teens, early 30s, and early 50s. Compared to the least active quartile, the second, third, and fourth quartiles of average lifetime strenuous physical activity yielded odds ratios of 0.82, 0.69, and 0.58 (95% CI, 0.41-0.83), respectively. Odds ratios for moderate activity generally suggested a modest, but not statistically significant, inverse association. Increased strenuous physical activity, throughout the lifespan, was associated with decreased risk of incident stomach cancer.