State of the epidemiological evidence on physical activity and cancer prevention.
Level 5 - mechanism / opinion, no new human data
Narrative review and population-attributable risk modeling without systematic review methodology reported
PubMed 20843488 · doi:10.1016/j.ejca.2010.07.028
What was done
The authors reviewed epidemiological evidence across multiple cancer sites (colon, breast, endometrium, lung, prostate, ovarian, gastric, rectal, pancreatic, bladder, testicular, kidney, and haematological) assessing strength, consistency, dose-response, and biological plausibility. They also modeled the population-attributable risk (PAR) for physical inactivity across 15 European countries.
What was found
Evidence was rated as convincing or probable for colon, breast, and endometrial cancers, weaker for ovarian, lung, and prostate cancers, and null or insufficient for other sites. An estimated 9% to 19% of major cancer cases—calculated as between 165,000 and 330,000 cases of six major cancers (breast, colon, lung, prostate, endometrium, ovarian) in 2008 in Europe—were attributed to physical inactivity. Proposed mechanisms included insulin resistance, body composition, sex steroid hormones, vitamin D, adipokines, inflammation, and immune function.
Why it matters
This synthesis contextualizes public health recommendations (30-60 minutes of moderate-to-vigorous activity at least 5 days per week) by quantifying the substantial cancer burden potentially preventable through physical activity.
Limits
As presented in the abstract, the review does not specify systematic review search criteria or the number of included studies. The population-attributable risk calculations rely on observational epidemiological data subject to confounding and measurement error.
Cited by
- supports In cancer prevention epidemiology, physical activity shows the strongest protective associations with colon and breast cancers, but little association with rectal or prostate cancers.