Wu X, Peng H, Wen Y, et al. - Researchers examined the link as well as causality between rheumatoid arthritis (RA) and the lung cancer (LC) risk via this meta-analysis and a Mendelian randomization study. They computed the relative risks and their 95% confidence intervals in the meta-analysis of cohort studies. To identify the results based on LC and histological subtypes, they conducted a two-sample Mendelian randomization (MR) analysis. They included 11 cohort studies with 183,888 patients. As per findings of meta-analysis, there was a relatively higher LC risk in relation to RA, but MR study did not support a causal link between genetically predisposed RA and LC risk. Male patients have a relatively higher LC risk vs female patients. An increased incidence of lung cancer in RA patients was found from 1950-2010. In the MR analysis, genetically predisposed RA was linked with a lower risk of LC, while neither causally correlated with the risk of lung adenocarcinoma nor squamous cell lung cancer.