Leisure-Time Physical Activity Reduces Risk of Multiple Cancer Types
In a study reported in JAMA Internal Medicine, Moore et al found that greater leisure-time physical activity was associated with a reduced risk for many types of cancer.
Study Details
The study used pooled data on 1.44 million adults from 12 prospective U.S. and European cohorts with self-reported physical activity, with a baseline of 1987 to 2004. Patients had a median age of 59 years, and 57% were women. A total of 186,932 cancers were reported.
Multivariable Cox regression was used to estimate hazard ratios (HRs) for associations of activity with the incidence of 26 types of cancer. Activity levels were modeled as cohort-specific percentiles on a continuous basis, and cohort-specific results were derived by meta-analysis of random effects. The hazard ratios for high vs low level of activity are for comparison of risk at the 90th (high) vs 10th percentiles. In seven cohorts for which metabolic equivalents (METs) could be calculated, the median activity level was 8 MET-h/wk, equivalent to 150 minutes of moderate-intensity activity (eg, walking) per week.
Risk Reductions
High vs low levels of activity were associated with lower risks of 13 cancers: esophageal adenocarcinoma (HR = 0.58, 95% confidence interval [CI] = 0.37–0.89), liver (HR = 0.73, 95% CI = 0.55–0.98), lung (HR = 0.74, 95% CI = 0.71–0.77), kidney (HR = 0.77, 95% CI = 0.70–0.85), gastric cardia (HR = 0.78, 95% CI = 0.64–0.95), endometrial (HR = 0.79, 95% CI = 0.68–0.92), myeloid leukemia (HR = 0.80, 95% CI = 0.70–0.92), myeloma (HR = 0.83, 95% CI 0.72–0.95), colon (HR = 0.84, 95% CI = 0.77–0.91), head and neck (HR = 0.85, 95% CI = 0.78–0.93), rectal (HR = 0.87, 95% CI = 0.80–0.95), bladder (HR = 0.87, 95% CI = 0.82–0.92), and breast (HR = 0.90, 95% CI = 0.87–0.93).
Associations were generally similar between overweight/obese and normal-weight individuals. Adjustment for body mass index somewhat decreased the risk reduction for esophageal adenocarcinoma and cancers of the liver, kidneys, and gastric cardia, but associations remained significant for 10 of the 13 cancers; of the 3 for which the association was no longer significant, the hazard ratio increased to 0.98 for endometrial cancer but remained consistent with a 15% to 20% lower risk for liver (0.81) and gastric cardia (0.85) cancers. The reduced risk for lung cancer was present in current and former smokers but not in individuals who had never smoked. Smoking status did not modify the association with other smoking-related cancers.
Greater activity was associated with a higher risk of malignant melanoma (HR = 1.27, 95% CI = 1.16–1.40) and prostate cancer (HR = 1.05, 95% CI = 1.03–1.08).
The investigators concluded: “Leisure-time physical activity was associated with lower risks of many cancer types. Health care 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 study was supported by the National Institutes of Health.
Steven C. Moore, PhD, MPH, of the National Cancer Institute, is the corresponding author of the JAMA Internal Medicine article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
