(HealthDay News) — Exercise may significantly reduce risk for many types of cancer, according to a large review published online in JAMA Internal Medicine.
Steven Moore, PhD, MPH, an investigator with the US National Cancer Institute, and colleagues pooled data from 12 US and European studies to create a database of 1.4 million adults, aged 19 to 98. They then examined whether self-reported leisure-time physical activity of moderate to vigorous intensity affected risk of 26 cancers.
Exercise was associated with a reduced risk for half of the cancers considered by the investigators, and that reduction remained significant for nearly all, even after accounting for factors such as obesity and smoking history. Overall, a higher level of physical activity was associated with a 7% lower risk of total cancer, the researchers found. The reduced risk ranged from 42% for esophageal cancer to 10% for breast cancer. For colon and lung cancer, the associated risk reduction was 16 and 26%, respectively. [RUN editor’s note: The risk of kidney cancer was reduced by 23% and rectal and bladder cancers by 13%. Leisure-time physical activity was associated with higher risk of prostate cancer by 5%.]
Physical activity reduces levels of hormones, such as estrogen, that have been linked to different cancers, and helps control levels of insulin and insulin-like growth factor, Moore told HealthDay. People who work out also tend to have lower levels of inflammation, Moore said. Their cells appear to be subject to less oxidative stress, and are more capable of repairing damaged DNA that might cause cancer, Marilie Gammon, PhD, of the Gillings School of Public Health at the University of North Carolina in Chapel Hill, and coauthor of an editorial accompanying the study, told HealthDay.
- 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. doi:10.1001/jamainternmed.2016.1548.
- McCullough LE, McClain KM, Gammon MD, et al. The Promise of Leisure-Time Physical Activity to Reduce Risk of Cancer Development. JAMA Intern Med. doi:10.1001/jamainternmed.2016.1521.