Table 1

Summary of epidemiological evidence on the association between physical activity and cancer by criteria for causality

Cancer siteConsistency of evidence for a risk reduction with increased physical activity levelsStrength of risk associationDose-responseTemporality (time period in life associated with risk reduction)Biological plausibilityOverall level of scientific evidence
Cohort studiesCase-control studiesTotal studiesRange of risk estimatesAverage risk reductionNo. of studies
Colon15 of 2023 of 2639 of 460.3 to 1.040–50%23 of 29Activity throughout life?Yes-several hypothesesConvincing
Breast8 of 1416 of 2224 of 360.3 to 1.630–40%15 of 23Early life?Yes-several hypothesesConvincing
Adult life?
Prostate10 of 165 of 1015 of 260.5 to 2.210–30%9 of 19Early life?Yes-some hypothesesProbable
Lung6 of 60 of 26 of 80.4 to 1.330–40%4 of 6UnknownUnclearPossible
Endometrial3 of 45 of 78 of 110.1 to 1.030–40%4 of 7UnknownYes-a few hypothesesPossible
Testicular0 of 23 of 63 of 80.5 to 3.320%3 of 5UnknownUnclearInsufficient
Ovarian1 of 31 of 22 of 50.3 to 2.10%2 of 3UnknownYes-a few hypothesesInsufficient