Leisure-time physical activity is associated with a lower risk for many types of cancer, including a 17 percent lower risk for myeloma. These key findings were independent of body size or smoking history, indicating that it is essential to educate inactive adults of the benefits of physical activity, with an emphasis on its influence in the development of many cancers.
The research paper, “Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults,” was published in JAMA Internal Medicine. The article is accompanied by an invited commentary from Emory University and University of North Carolina researchers.
Cancer is one of the leading causes of mortality and morbidity worldwide. The American Cancer Society estimates that in 2016 there will be 1,685,210 new cancer cases diagnosed and 595,690 cancer deaths in the U.S. alone. The increasing incidence of cancer, especially in emerging economies where unhealthy lifestyles predominate, also results in a great economic burden, which points to the need for preventive public healthcare strategies to halt the growing incidence of cancer worldwide. Leisure-time activity has been associated with lower risk for certain conditions, such as heart disease and all-cause mortality, but its influence on cancer risk has not been clearly defined.
Researchers wanted to determine if this type of physical activity is associated with a lower risk for common cancer types and the relation of such association with body type and smoking habits. The researchers pooled data from 12 U.S. and European cohorts, where participants had reported their level of physical activity. The study included a total of 1.44 million participants and 186,932 cancers. Higher levels of physical activity were associated with lower levels of 13 of the 26 cancers assessed, namely 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).
Overall, higher levels of physical activity were associated with a 7 percent lower risk of total cancer. Most of these associations remained regardless of body type and smoking habit history. Notably, more physical activity was associated with 5 percent higher risk of prostate cancer and a 27 percent higher risk of malignant melanoma. However, this last association was only significant in regions with high levels of ultraviolet radiation.
“Leisure-time physical activity was associated with lower risks of many cancer types. Healthcare professionals counseling inactive adults should emphasize that most of these associations were evident regardless of body size or smoking history, supporting broad generalizability of findings,” the researchers concluded.