Meta-analysis of the association between indoor environmental pollution and lung cancer risk in never-smokers.

Objective: This review systematically evaluates the association between indoor environmental pollution and lung cancer risk in never-smokers by meta-analysis, providing evidence-based prevention strategies for lung cancer.

Methods: This study was registered in PROSPERO (Registration No.: CRD420251008009) following the Preferred Reporting Items for Systematic Reviews and Meta - Analyses (PRISMA) guidelines. A systematic search was conducted in the PubMed, Web of Science, Embase, and Cochrane Library databases for relevant studies published from March 2005 to March 2025. Literature screening was conducted independently by two reviewers using a double-blind method. Study quality was assessed using the criteria recommended by the Agency for Healthcare Research and Quality (AHRQ). Meta-analysis was performed using STATA 12.0 and RevMan 5.3 software.

Results: A total of 22 studies met the inclusion criteria. Analysis showed that indoor environmental pollutants, including residential radon (Odds Ratio [OR] = 1.82, 95% CI: 1.31-2.54), environmental tobacco smoke (ETS) (OR = 1.96, 95% CI: 1.36-2.82), cooking fumes (OR = 3.68, 95% CI: 2.67-5.07), cooking methods (deep-frying: OR = 1.60, 95% CI: 0.72-3.52; stir-frying: OR = 1.12, 95% CI: 1.07-1.17), and the use of solid fuels (OR = 5.54, 95% CI: 3.15-9.72) were all significantly associated with an increased risk of lung cancer in non-smoking populations. In addition, the study found that residential environmental pollution, occupational exposures, and low body mass index (BMI) were also significant factors for lung cancer in non-smoking patients.

Conclusion: This study confirmed that indoor environmental pollutants, including residential radon, ETS, cooking fumes, specific cooking methods (deep-frying and stir-frying), and the solid fuel use, are significantly associated with an increased risk of lung cancer in non-smoking populations. Furthermore, exposure to outdoor pollutants in residential areas and occupational environments cannot be ignored.