Ang L, Chan CPY, Yau WP, et al. - Whether and how familial risk of lung cancer is impacted by socio-demographic factors and geographical regions was investigated in this systematic review and meta-analysis involving 85 studies (19 cohort and 66 case control studies) identified by systematically searching PubMed and Embase until October 1, 2019. The reported risk of familial lung cancer was higher among Asians vs non-Asians, younger people (age ≤ 50) vs older persons (age > 50), people with ≥2 affected relatives vs individuals with only one, ever-smokers vs never-smokers, Asian women vs Western women, and never-smokers in Asia vs never-smokers in the West. Overall, the impact of both genetic and environmental factors on familial risk of lung cancer was evident in this study.