The effect of dietary patterns on lung cancer risk is currently debated. In this study, we evaluated the association between different "a posteriori" dietary patterns and lung cancer risk. The search was carried out (February 2023) through Scopus, Web of Science, and PubMed databases. Meta-analysis was performed by a random-effects model using risk values (RR and OR) extracted from the 12 selected studies. Two main dietary patterns were identified and named "Western/meat" and "Healthy/prudent". The highest adherence to the "Western/meat" dietary pattern significantly increased the lung cancer risk (OR = 1.39; 95% CI: 1.17-1.65; p = 0.0002) while the highest adherence to the "Healthy/prudent" pattern reduced it (OR = 0.65; 95% CI: 0.51-0.83; p = 0.001). A linear trend between both dietary patterns and lung cancer risk was observed. However, a statistically significant inverse dose-response trend was found only for the "Healthy/prudent" dietary pattern (regression coefficient = -0.0031, p = 0.003). Subgroup analyses showed that the "Western/meat" pattern significantly increased the lung cancer risk in former (n = 4) (OR = 1.93, 95% CI: 1.11-3.36) and current smokers (n = 7) (OR = 1.35, 95% CI: 1.06-1.71). Similarly, the "Healthy/prudent" pattern exerts a protective effect on former (n = 4) (OR = 0.61, 95% CI: 0.44-0.85) and current smokers (n = 8) (OR = 0.64, 95% CI: 0.46-0.88). For both dietary patterns, no significant effect was observed on never-smokers.
Keywords: Western/meat; dietary patterns; dose–response meta-analysis; healthy/prudent; lung cancer; principle component analysis.