Being physically active may lower your cancer risk

Higher levels of leisure-time physical activity may lower your risk for 13 types of cancers, according to a new study published online by JAMA Internal Medicine.

Steven C. Moore, Ph.D., M.P.H., of the National Cancer Institute, Bethesda, Md., and coauthors pooled data from 12 U.S. and European cohorts (groups of study participants) with self-reported physical activity (1987-2004). They analyzed associations of physical activity with the incidence of 26 kinds of cancer.

The study included 1.4 million participants and 186,932 cancers were identified during a median of 11 years of follow-up.

They observed a 10 percent lower risk of breast cancer and a 21 percent lower risk of uterine cancer among those with higher levels of physical activity. Overall, a higher level of physical activity was associated with a 7 percent lower risk of total cancer and most of the associations remained regardless of body size or smoking history, according to the article.

Higher levels of physical activity compared to lower levels were associated with lower risks of 13 of 26 cancers: 

• esophageal adenocarcinoma (42 percent lower risk); 
• liver (27 percent lower risk); 
• lung (26 percent lower risk); 
• kidney (23 percent lower risk); 
• gastric cardia (22 percent lower risk); 
• endometrial (21 percent lower risk); 
• myeloid leukemia (20 percent lower risk); 
• myeloma (17 percent lower risk); 
• colon (16 percent lower risk); 
• head and neck (15 percent lower risk), 
• rectal (13 percent lower risk); 
• bladder (13 percent lower risk); and 
• breast (10 percent lower risk). 

The authors note the main limitation of their study is that they cannot fully exclude the possibility that diet, smoking and other factors may affect the results. Also, the study used self-reported physical activity, which can mean errors in recall.