Physical activity and risk of cancer mortality in patients with and without cancer: is there a dose-response relationship?

Background: The purpose of this study was to examine a dose-response association between aerobic physical activity (APA) and muscle-strengthening exercise (MSE) and their combinations with cancer mortality.

Methods: The final 575,439 participants involved in this study were derived from 1997 to 2018 longitudinal follow-up data collected in the National Health Interview Survey (NHIS). The APA and MSE were requested via self-reported questionnaires. These records are linked to the National Death Index and classified as cancer deaths based on the International Classification of Diseases (ICD-10). Statistical analysis was performed by Wilcoxon rank-sum test, chi-square test, and the Cox proportional hazards models.

Results: After adjusting for all covariates, the results demonstrated that the cancer mortality risk for cancer survivors decreased by 23.2%, 35.8%, 42.5%, and 46.7% for those engaging in 0-7.4 MET hours/week, 7.5-14.9 MET hours/week, 15-29.9 MET hours/week, and 30 + MET hours/week, respectively. For non-cancer patients, the cancer mortality risk decreased by 6.9%, 11.9%, 15.1%, and 16.7%. Furthermore, the results showed that the cancer mortality risk for cancer survivors decreased by 34.9%, 30.2%, 32.3%, and 10% for those engaging in 2-3 times/week, 4-5 times/week, 6-7 times/week, and 8 + times/week. For non-cancer patients, the cancer mortality risk decreased by 17.4%, 23.7%, 9.5%, and 10.6%. Among non-cancer patients with insufficient MSE, there was no significant negative correlation between APA and cancer mortality.

Conclusion: The optimal dose response in reducing the risk of cancer mortality may occur at higher levels of APA with MSE 4-5 times/week and 2-3 times/week for primary and secondary prevention. In addition, primary prevention derives a greater advantage from MSE, and a protocol of APA should be emphasized in secondary prevention.