Ang L, Chan CPY, Yau WP, et al. - A systematic review and meta-analysis were conducted to evaluate the contributions of sociodemographic factors and geographical regions on family history of lung cancer and lung cancer risk. Researchers surveyed PubMed and Embase until October 1, 2019 and found 84 articles (19 cohort and 66 case-control studies) to include in this systematic review and meta-analysis. They calculated pooled summary estimates and 95% confidence intervals, and stratified the analysis by sociodemographic factors and geographical regions. Geographical regions, sex, age of proband, smoking status, type of first-degree relatives, number of affected relatives, and early onset of lung cancer in affected relatives were significant determinants of familial risk of lung cancer. There was a greater risk of familial lung cancer among Asians vs non-Asians, younger individuals (age≤50) vs older individuals (age>50), individuals with ≥2 affected relatives vs those with one affected relative, ever-smokers vs never-smokers, Asian females vs Western females, and never-smokers in Asia vs never-smokers in the West. Further trials should control for environmental factors such as air pollution and environmental tobacco smoke which are prevalent in Asia.