The following is a summary of the “Physical activity and risk of lung cancer: A systematic review and dose-response meta-analysis of cohort studies,” published in the March 2023 issue of Cancer by Qie, et al.

To synthesize knowledge about the relationship between total physical activity (TPA), leisure-time physical activity (LTPA), occupational, physical activity (OPA), and lung cancer risk, as well as to investigate the dose-response relationship between LTPA level and lung cancer. Up until November 17, 2021, PubMed and Web of Science were searched. A random-effects or fixed-effects model was used to calculate the summary relative risks (RRs) and 95% CIs. The dose-response analysis was carried out using constrained cubic splines.

They found 25 articles (42 cohort studies) examining the relationship between physical activity and lung cancer, with 9,983,295 study participants and 85,988 incident cases. When the highest level of TPA and LTPA was compared to the lowest level, lung cancer risk was reduced by 22% (RR, 0.78; 95% CI: 0.70, 0.86) and 12% (RR, 0.88; 95% CI: 0.83, 0.93), respectively. 

They discovered a roughly U-shaped relationship between LTPA and lung cancer (P_{non-linearity}<0.001), with the lowest risk at 15 metabolic equivalents of task hours per week (h/wk) of LTPA. Lung cancer risk increased significantly among those unemployed (RR, 1.33; 95% CI: 1.17, 1.51) or had standing occupations (RR, 1.37; 95% CI: 1.15, 1.63) but not among those who had light or high OPA. Their meta-analysis found that TPA and LTPA, but not OPA, reduced the risk of lung cancer. The discovery of a U-shaped relationship between LTPA and lung cancer risk merits further investigation.

Source: sciencedirect.com/science/article/pii/S2667005423000029