The article by Warburton and colleagues [BCMJ 2016;58:210-218] reports on the risk-benefit paradox of exercise. There is a transient increase in short-term risk for an adverse cardiac event with vigorous exercise and a reduction in long-term risk for chronic disease and premature mortality with relatively small amounts of exercise.
The recently published pooled analysis by Moore and colleagues on leisure-time physical activity in the risk of cancer development provides a different paradox. Leisure-time physical activity is found to be associated with lower risks of approximately half (13) of the cancer types regardless of BMI or smoking status. They include esophageal adenocarcinoma, liver, lung, kidney, gastric cardia, endometrial, myeloid leukaemia (20% or more lower risk), and others. In contrast, there is an increased risk in prostate cancer (5% higher risk) and melanoma (up to 27% higher risk), although the former may be related to screening bias and the latter to UV exposure.
The invited commentary on the Moore article by McCullough and colleagues suggests further research is needed to assess the critical timing of physical activity needed for optimal cancer risk reduction. Clarification is also needed on the types and amount of leisure-time activity (e.g., running, cycling, or walking).
There is a risk-benefit paradox of exercise in cardiac adverse complication/prevention and cancer risk.
—H.C. George Wong, MD
1. Moore SC, Lee IM, Weiderpass E, et al. Association of leisure-time physical activity with risk of 26 types of cancer in 1.44 million adults. JAMA Intern Med 2016;doi:10.1001/jamainternmed.2016.1548 [e-pub ahead of print].
Above is the information needed to cite this article in your paper or presentation. The International Committee
of Medical Journal Editors (ICMJE) recommends the following citation style, which is the now nearly universally
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Halpern SD, Ubel PA, Caplan AL, Marion DW, Palmer AM, Schiding JK, et al. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002;347:284-7.
About the ICMJE and citation styles
The ICMJE is small group of editors of general medical journals who first met informally in Vancouver, British Columbia, in 1978 to establish guidelines for the format of manuscripts submitted to their journals. The group became known as the Vancouver Group. Its requirements for manuscripts, including formats for bibliographic references developed by the U.S. National Library of Medicine (NLM), were first published in 1979. The Vancouver Group expanded and evolved into the International Committee of Medical Journal Editors (ICMJE), which meets annually. The ICMJE created the Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals to help authors and editors create and distribute accurate, clear, easily accessible reports of biomedical studies.
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