Family Socioeconomic Position and Lung Cancer Risk: A Meta-analysis and a Mendelian Randomization Study

Background: Family socioeconomic position (SEP) in childhood is an important factor to predict some chronic diseases. However, the association between family SEP in childhood and the risk of lung cancer is not clear. Methods: A systematic search was performed to explore their relationship. We selected education level, socioeconomic positions of parents and childhood housing conditions to represent an individual family SEP. Hazard ratios (HRs) of lung cancer specific-mortality were synthesized using a random effects model. Two-sample Mendelian randomization (MR) was carried out with summary data from published genome-wide association studies of SEP to assess the possible causal relationship of SEP and risk of lung cancer. Results: Through meta-analysis of 13 studies, we observed that poorer SEP was associated with increased lung cancer risk (HR: 1.25, 95% CI: 1.10, 1.43). In addition, the dose-response analysis revealed a negative correlation between SEP in childhood and lung cancer in adulthood. Same conclusion was reached in MR [(education level) OR 0.50, 95% CI: 0.39, 0.63; P <0.001]. Conclusions: This study indicates that poor family SEP in childhood is a causal risk factor for lung cancer. We believe this population may receive greater benefit from lung cancer screening programs. Systematic review registration Prospero ID: 159082