Amount and Intensity of Leisure-Time Physical Activity and Lower Cancer Risk

Abstract

Purpose: To determine whether recommended amounts of leisure-time physical activity (ie, 7.5-15 metabolic equivalent task [MET] hours/week) are associated with lower cancer risk, describe the shape of the dose-response relationship, and explore associations with moderate- and vigorous-intensity physical activity.

Methods: Data from 9 prospective cohorts with self-reported leisure-time physical activity and follow-up for cancer incidence were pooled. Multivariable Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% CIs of the relationships between physical activity with incidence of 15 types of cancer. Dose-response relationships were modeled with restricted cubic spline functions that compared 7.5, 15.0, 22.5, and 30.0 MET hours/week to no leisure-time physical activity, and statistically significant associations were determined using tests for trend (P < .05) and 95% CIs (< 1.0).

Results: A total of 755,459 participants (median age, 62 years [range, 32-91 years]; 53% female) were followed for 10.1 years, and 50,620 incident cancers accrued. Engagement in recommended amounts of activity (7.5-15 MET hours/week) was associated with a statistically significant lower risk of 7 of the 15 cancer types studied, including colon (8%-14% lower risk in men), breast (6%-10% lower risk), endometrial (10%-18% lower risk), kidney (11%-17% lower risk), myeloma (14%-19% lower risk), liver (18%-27% lower risk), and non-Hodgkin lymphoma (11%-18% lower risk in women). The dose response was linear in shape for half of the associations and nonlinear for the others. Results for moderate- and vigorous-intensity leisure-time physical activity were mixed. Adjustment for body mass index eliminated the association with endometrial cancer but had limited effect on other cancer types.

Conclusion: Health care providers, fitness professionals, and public health practitioners should encourage adults to adopt and maintain physical activity at recommended levels to lower risks of multiple cancers.

FIG 1.

(A) Leisure-time physical activity (metabolic equivalent task [MET]–hours/week) and risk of cancer sites with strong evidence of association. (B) Association between leisure-time physical activity (MET hours/week) and cancer sites with moderate or lower evidence of association. Analysis is adjusted for entry age, sex, race, education, smoking, and alcohol intake. For breast and endometrial cancer, we also adjusted for postmenopausal hormone treatment, age at menarche and menopause, parity, and oral contraceptive use. Restricted cubic splines were fit with 3 knots placed at the 5th, 50th, and 95th percentiles of physical activity. Shaded area indicates recommended amounts of physical activity. Cancer sites were judged as strong evidence of association by the 2018 US Physical Activity Guidelines Advisory Committee.

FIG 2.

Mutually adjusted associations (hazard ratios with 95% CIs) between moderate- and vigorous-intensity activity and cancers with statistically significant associations with overall leisure-time physical activity. Analysis is adjusted for standard covariates and moderate- and vigorous-intensity activity as necessary. (*) P < .05, nonlinear association. n = number of participants with a given type of cancer.