Mendelian randomization study indicates lack of causal relationship between physical activity and lung cancer.

Abstract

Previous researches have indicated physical activity (PA) may be associated with lower risk of lung cancer. However, causal relationship between PA and risk of lung cancer is not clear. We aimed to inspect the causal effect of PA on lung cancer. We analyzed summary data of accelerator-measured PA and lung cancer from the genome-wide association study (GWAS) using two-sample Mendelian randomization (MR) method. We obtained summary data of accelerator-measured PA from UK Biobank, data of lung cancer patients from Consortium and International Lung Cancer Consortium (ILCCO) to investigate possible causal effect of PA on lung cancer. According to result of MR using inverse variance weighted method (IVW), we found that genetically predicted higher PA level did not causally decrease risk of lung cancer (OR 0.95, 95% CI 0.88-1.03, p = 0.238). Results of MR-Egger and weighted median method were consistent with IVW method. Our mendelian randomization study showed that genetically higher PA is not causally associated with risk of lung cancer. More researches are needed to investigate relationship between PA and lung cancer.