Elsevier

European Journal of Cancer

Volume 46, Issue 14, September 2010, Pages 2593-2604
European Journal of Cancer

State of the epidemiological evidence on physical activity and cancer prevention

https://doi.org/10.1016/j.ejca.2010.07.028Get rights and content

Abstract

Background

Physical activity is a modifiable lifestyle risk factor that has the potential to reduce the risk of most major cancer sites.

Methods

We examined the strength, consistency, dose–response and biological plausibility of an association between physical activity and risk of colon, breast, endometrium, lung, prostate, ovarian, gastric, rectal, pancreatic, bladder, testicular, kidney and haematological cancers. We also estimated the population-attributable risk (PAR) for physical inactivity and cancer in 15 European countries.

Results

There is convincing or probable evidence for a beneficial effect of physical activity on the risk of colon, breast and endometrial cancers. The evidence is weaker for ovarian, lung and prostate cancers and generally either null or insufficient for all remaining cancers. Several hypothesised biological mechanisms include a likely effect of physical activity on insulin resistance, body composition, sex steroid hormones and a possible effect on vitamin D, adipokines, inflammation and immune function. Somewhere between 165,000 and 330,000 cases of the six major cancers (breast, colon, lung, prostate, endometrium and ovarian) could have been prevented in 2008 in Europe alone if the population had maintained sufficient levels of physical activity.

Conclusion

There is strong and consistent evidence that physical activity reduces the risk of several of the major cancer sites, and that between 9% and 19% of cancer cases could be attributed to lack of sufficient physical activity in Europe. Public health recommendations for physical activity and cancer prevention generally suggest 30–60 min of moderate or vigorous-intensity activity done at least 5 d per week.

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)

  • A.K. Samad et al.

    A meta-analysis of the association of physical activity with reduced risk of colorectal cancer

    Colorectal Dis

    (2005)
  • D.J. Harriss et al.

    Lifestyle factors and colorectal cancer risk (2): a systematic review and meta-analysis of associations with leisure-time physical activity

    Colorectal Dis

    (2009)
  • R.R. Huxley et al.

    The impact of dietary and lifestyle risk factors on risk of colorectal cancer: a quantitative overview of the epidemiological evidence

    Int J Cancer

    (2009)
  • M.L. Slattery

    Physical activity and colorectal cancer

    Sports Med

    (2004)
  • L.H. Kushi et al.

    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

    (2006)
  • A. Chao et al.

    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

    (2004)
  • E. White et al.

    Physical activity in relation to colon cancer in middle-aged men and women

    Am J Epidemiol

    (1996)
  • L. Le Marchand et al.

    Associations of sedentary lifestyle, obesity, smoking, alcohol use, and diabetes with the risk of colorectal cancer

    Cancer Res

    (1997)
  • I. Thune et al.

    Physical activity and risk of colorectal cancer in men and women

    Br J Cancer

    (1996)
  • M.L. Slattery et al.

    Lifestyle and colon cancer: an assessment of factors associated with risk

    Am J Epidemiol

    (1999)
  • K.Y. Wolin et al.

    Leisure-time physical activity patterns and risk of colon cancer in women

    Int J Cancer

    (2007)
  • C. Friedenreich et al.

    Physical activity and risk of colon and rectal cancers: the European prospective investigation into cancer and nutrition

    Cancer Epidemiol Biomarkers Prev

    (2006)
  • C.M. Friedenreich et al.

    Physical activity and breast cancer risk: impact of timing, type and dose of activity and population subgroup effects

    Brit J Sports Med

    (2008)
  • E.M. Monninkhof et al.

    Physical activity and breast cancer: a systematic review

    Epidemiology

    (2007)
  • A.E. Cust et al.

    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

    (2007)
  • D.W. Voskuil et al.

    Physical activity and endometrial cancer risk, a systematic review of current evidence

    Cancer Epidemiol Biomarkers Prev

    (2007)
  • E. Friberg et al.

    Physical activity and risk of endometrial cancer: a population-based prospective cohort study

    Cancer Epidemiol Biomarkers Prev

    (2006)
  • A.V. Patel et al.

    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

    (2008)
  • G.L. Gierach et al.

    Physical activity, sedentary behavior, and endometrial cancer risk in the NIH-AARP diet and health study

    Int J Cancer

    (2009)
  • A. Tardon et al.

    Leisure-time physical activity and lung cancer: a meta-analysis

    Cancer Causes Control

    (2005)
  • M.F. Leitzmann et al.

    Prospective study of physical activity and lung cancer by histologic type in current, former, and never smokers

    Am J Epidemiol

    (2009)
  • H.A. Wakelee et al.

    Lung cancer incidence in never smokers

    J Clin Oncol

    (2007)
  • J. Subramanian et al.

    Lung cancer in never smokers: a review

    J Clin Oncol

    (2007)
  • S.Y. Pan et al.

    Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

    Methods Mol Biol

    (2009)
  • S.C. Moore et al.

    Physical activity in relation to total, advanced, and fatal prostate cancer

    Cancer Epidemiol Biomarkers Prev

    (2008)
  • C.M. Friedenreich et al.

    Case–control study of lifetime total physical activity and prostate cancer risk

    Am J Epidemiol

    (2004)
  • N. Orsini et al.

    A prospective study of lifetime physical activity and prostate cancer incidence and mortality

    Br J Cancer

    (2009)
  • C.M. Olsen et al.

    Recreational physical activity and epithelial ovarian cancer: a case–control study, systematic review, and meta-analysis

    Cancer Epidemiol Biomarkers Prev

    (2007)
  • A.V. Patel et al.

    Recreational physical activity and sedentary behavior in relation to ovarian cancer risk in a large cohort of US women

    Am J Epidemiol

    (2006)
  • M. Zhang et al.

    Sedentary behaviours and epithelial ovarian cancer risk

    Cancer Causes Control

    (2004)
  • J.P. Anderson et al.

    Anthropometric variables, physical activity, and incidence of ovarian cancer: the Iowa women’s health study

    Cancer

    (2004)
  • E.R. Bertone et al.

    Prospective study of recreational physical activity and ovarian cancer

    J Natl Cancer Inst

    (2001)
  • N. Carnide et al.

    Association between frequency and intensity of recreational physical activity and epithelial ovarian cancer risk by age period

    Eur J Cancer Prev

    (2009)
  • M.F. Leitzmann et al.

    Prospective study of physical activity and the risk of ovarian cancer

    Cancer Causes Control

    (2009)
  • S.Y. Pan et al.

    Physical activity and the risk of ovarian cancer: a case–control study in Canada

    Int J Cancer

    (2005)
  • M.A. Rossing et al.

    Recreational physical activity and risk of epithelial ovarian cancer

    Cancer Causes Control

    (2010)
  • P. Schnohr et al.

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

    Scand J Public Health

    (2005)
  • E.R. Bertone et al.

    Recreational physical activity and ovarian cancer in a population-based case–control study

    Int J Cancer

    (2002)
  • L.M. Hannan et al.

    Physical activity and risk of ovarian cancer: a prospective cohort study in the United States

    Cancer Epidemiol Biomarkers Prev

    (2004)
  • D. Albanes et al.

    Physical activity and risk of cancer in the NHANES I population

    Am J Public Health

    (1989)
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