Researchers from Japan have reported that increased
daily physical activity decreases the risk of cancer development in a
“relatively lean population”. The details of this study appeared in the
August 15, 2008 issue of the American Journal of Epidemiology.1
Increased physical activity has been associated with a decreased risk of
breast cancer. However, the impact of exercise on other cancers has not
been well studied. Studies of exercise can also be confounded by dietary
habits and obesity which may also have an impact on cancer risk. At
least one study has shown that exercise does not compensate for the
increased cancer risk in obese women. The current study is of major
interest since it was carried out in a predominantly lean population in
Japan.
Researchers affiliated with the Japan Public Health-Center-based Prospective
Study evaluated cancer risks in almost 80,000 persons aged 45-74 years. They
reported that the risk reduction for developing all types of cancer were
reduced by 13% in men and 16% in women with the highest level of physical
activity compared to the lowest level of activity. These authors also stated
that the effect was greater in women than men especially in the elderly. The
main sites affected in men were colon, liver and pancreas and the main site
affected in women was the stomach.
