State of the epidemiological evidence on physical activity and cancer prevention
Introduction
The past 20 years of epidemiological research has generated a large body of evidence describing the benefits of physical activity in relation to cancer risk. Despite great progress in understanding this association, particularly with respect to colon and breast cancers, there is still uncertainty regarding the strength, consistency and dose–response of the associations between physical activity and most other cancer sites. It is also unclear what type, timing and dose of activity are required for significant benefit and also the population sub-groups that experience a reduced cancer risk with physical activity. To address the state of the knowledge surrounding these questions, we will provide an overview of the existing epidemiological evidence relating physical activity to cancer risk. Using the latest published literature, we also estimate the proportion of cancers that are attributable to inadequate physical activity levels in Europe and describe briefly some proposed biological mechanisms explaining physical activity–cancer relations. We finally highlight areas for future research.
Section snippets
Epidemiological evidence for an association between physical activity and cancer
The association between physical activity and all cancer sites has been systematically reviewed by national1 and international agencies2, 3 as well as by individual scientists.4, 5 The level of epidemiological evidence varies by cancer site. There is now convincing evidence for a beneficial effect of physical activity on the risk of colon cancer, probable evidence for an effect on breast and endometrial cancers, possible evidence for an effect on cancers of the prostate, lung and ovary, and
Population-attributable risks in Europe
From a public health perspective, a need exists to examine the burden of cancer that might be preventable if risks associated with a specific lifestyle factor could be removed or, at least minimised in a population. To estimate the cancer burden in Europe attributable to physical inactivity, we used physical activity estimates generated by Eurobarometer, Wave 58.2 conducted in 15 European Union countries in 200258 and estimates of gender-specific cancer incidence in 2008 reported by Ferlay and
Hypothesised biological mechanisms
For those cancers that are convincingly, probably or possibly related to physical inactivity, an understanding of the underlying biological mechanisms adds plausibility to the association, identifies specific targets for cancer prevention and helps guide future public health recommendations. Across the six cancer sites discussed earlier in this review, numerous biological pathways have been hypothesised and in some cases tested in randomised controlled trials (RCTs).2, 3, 66, 67, 68Table 3
Limitations of the existing evidence and future research directions
Several limitations exist in this field of cancer research that need to be considered, particularly when articulating new research directions. These include the difficulty in assessing physical activity, the limited number of controlled exercise intervention trials that have been specifically designed to examine the underlying biological mechanisms and the complete lack of randomised controlled trials of exercise for cancer prevention.
Inherent in observational epidemiological studies of
Conclusion
The quantity and quality of research on physical activity and cancer have increased exponentially in the past 20 years with a large body of evidence that is now becoming established and increasingly recognised worldwide. Physical activity is recognised as a modifiable lifestyle risk factor for most chronic diseases, including cancer, by international agencies.1, 2, 3 Evidence for the underlying biological mechanisms involved in the pathways between physical activity and cancer risk is also
Funding
Dr. Christine Friedenreich was supported by a Health Senior Scholar Award from the Alberta Heritage Foundation for Medical Research. Dr. Brigid Lynch was supported by a National Health and Medical Research Council Public Health Training Fellowship (#586727).
Conflict of interest statement
None declared.
Acknowledgement
The authors would like to thank Dr. Isabelle Soerjomataram for the Eurobarometer study data that were used in this manuscript in the estimation of the population-attributable risks.
References (107)
- et al.
Physical activity and esophageal and gastric carcinoma in a large prospective study
Am J Prev Med
(2009) - et al.
Estimates of cancer incidence and mortality in Europe in 2008
Eur J Cancer
(2010) - et al.
Lifestyle changes and reduction of colon cancer incidence in Europe: a scenario study of physical activity promotion and weight reduction
Eur J Cancer
(2010) - et al.
Prospective study of the association of changes in dietary intake, physical activity, alcohol consumption, and smoking with 9-y gain in waist circumference among 16,587 US men
Am J Clin Nutr
(2003) - Physical activity guidelines advisory committee. Physical activity guidelines advisory committee report, 2008....
- IARC working group. IARC handbook of cancer prevention, volume 6: weight control and physical activity. Lyon: IARC;...
- World Cancer Research Fund and the American Institute for Cancer Research. Food, nutrition, physical activity, and the...
Physical activity and cancer prevention: from observational to intervention research
Cancer Epidemiol Biomarkers Prev
(2001)- et al.
Physical activity
- et al.
Physical activity and colon cancer prevention: a meta-analysis
Br J Cancer
(2009)
A meta-analysis of the association of physical activity with reduced risk of colorectal cancer
Colorectal Dis
Lifestyle factors and colorectal cancer risk (2): a systematic review and meta-analysis of associations with leisure-time physical activity
Colorectal Dis
The impact of dietary and lifestyle risk factors on risk of colorectal cancer: a quantitative overview of the epidemiological evidence
Int J Cancer
Physical activity and colorectal cancer
Sports Med
American Cancer Society Guidelines on Nutrition and Physical Activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity
CA Cancer J Clin
Amount, type, and timing of recreational physical activity in relation to colon and rectal cancer in older adults: the cancer prevention study II nutrition cohort
Cancer Epidemiol Biomarkers Prev
Physical activity in relation to colon cancer in middle-aged men and women
Am J Epidemiol
Associations of sedentary lifestyle, obesity, smoking, alcohol use, and diabetes with the risk of colorectal cancer
Cancer Res
Physical activity and risk of colorectal cancer in men and women
Br J Cancer
Lifestyle and colon cancer: an assessment of factors associated with risk
Am J Epidemiol
Leisure-time physical activity patterns and risk of colon cancer in women
Int J Cancer
Physical activity and risk of colon and rectal cancers: the European prospective investigation into cancer and nutrition
Cancer Epidemiol Biomarkers Prev
Physical activity and breast cancer risk: impact of timing, type and dose of activity and population subgroup effects
Brit J Sports Med
Physical activity and breast cancer: a systematic review
Epidemiology
Physical activity and endometrial cancer risk: a review of the current evidence, biologic mechanisms and the quality of physical activity assessment methods
Cancer Causes Control
Physical activity and endometrial cancer risk, a systematic review of current evidence
Cancer Epidemiol Biomarkers Prev
Physical activity and risk of endometrial cancer: a population-based prospective cohort study
Cancer Epidemiol Biomarkers Prev
The role of body weight in the relationship between physical activity and endometrial cancer: results from a large cohort of US women
Int J Cancer
Physical activity, sedentary behavior, and endometrial cancer risk in the NIH-AARP diet and health study
Int J Cancer
Leisure-time physical activity and lung cancer: a meta-analysis
Cancer Causes Control
Prospective study of physical activity and lung cancer by histologic type in current, former, and never smokers
Am J Epidemiol
Lung cancer incidence in never smokers
J Clin Oncol
Lung cancer in never smokers: a review
J Clin Oncol
Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence
Methods Mol Biol
Physical activity in relation to total, advanced, and fatal prostate cancer
Cancer Epidemiol Biomarkers Prev
Case–control study of lifetime total physical activity and prostate cancer risk
Am J Epidemiol
A prospective study of lifetime physical activity and prostate cancer incidence and mortality
Br J Cancer
Recreational physical activity and epithelial ovarian cancer: a case–control study, systematic review, and meta-analysis
Cancer Epidemiol Biomarkers Prev
Recreational physical activity and sedentary behavior in relation to ovarian cancer risk in a large cohort of US women
Am J Epidemiol
Sedentary behaviours and epithelial ovarian cancer risk
Cancer Causes Control
Anthropometric variables, physical activity, and incidence of ovarian cancer: the Iowa women’s health study
Cancer
Prospective study of recreational physical activity and ovarian cancer
J Natl Cancer Inst
Association between frequency and intensity of recreational physical activity and epithelial ovarian cancer risk by age period
Eur J Cancer Prev
Prospective study of physical activity and the risk of ovarian cancer
Cancer Causes Control
Physical activity and the risk of ovarian cancer: a case–control study in Canada
Int J Cancer
Recreational physical activity and risk of epithelial ovarian cancer
Cancer Causes Control
Physical activity in leisure-time and risk of cancer: 14-year follow-up of 28,000 Danish men and women
Scand J Public Health
Recreational physical activity and ovarian cancer in a population-based case–control study
Int J Cancer
Physical activity and risk of ovarian cancer: a prospective cohort study in the United States
Cancer Epidemiol Biomarkers Prev
Physical activity and risk of cancer in the NHANES I population
Am J Public Health
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