Physical Activity Lowers Risk of Several Cancers

Physical activity lowers the risk of several cancers A very large international study led by the US National Institutes of Health, has concluded that people with the highest levels of leisure-time physical activity have a reduced risk of 13 of 26 types of cancer studied.

Data was pooled from 12 studies that together followed a total of 1.44 million people over time. Participants were 19 to 98 years old and from the United States and Europe, 57% female, and with no history of cancer. The studies assessed physical activity by using surveys that asked about time spent in moderate to vigorous leisure-time physical activities, such as walking, running, or swimming. The median level of activity was about 150 minutes of moderate-intensity work per week. This is comparable to the minimum level of physical activity that experts recommend. Participants were followed for a median of 11 years.

The researchers found that people with the highest level of leisure-time physical activity had a reduced risk for 13 of 26 types of cancer compared to those with the lowest level of activity. People with the highest activity had a 20% lower risk for 7 cancer types: oesophageal adenocarcinoma, liver, lung, kidney, gastric cardia, endometrial, and myeloid leukemia. They also had a 10-20% lower risk for myeloma and cancers of the head and neck, rectum, bladder and breast.

Factors such as age, sex, smoking, alcohol, diet, education, ethnicity and body mass index (BMI) were controlled for. Ten of the 13 associations remained after adjusting for BMI. This suggests that for the majority of cancers, physical activity reduces risk through mechanisms other than lowering body weight.

(Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults. JAMA Internal Medicine, online 16 May 2016.)