Associations between diet and incidence risk of lung cancer: A Mendelian randomization study

Observational studies have revealed associations between diet and lung cancer. However, it is unclear whether the association is disturbed by confounding factors. We used a two-sample Mendelian randomization (MR) method to characterize the associations between diet and the lung cancer risk (including 3 subtypes: lung adenocarcinoma (LA), squamous cell lung carcinoma (SqCLC), and small cell lung cancer (SCLC)).

Data on 20 diets were screened from the UK Biobank. Lung cancer data came from a large meta-analysis of 85,716 individuals. The inverse-variance weighted method was used as the main analysis. Sensitivity analysis was also used to explain the different multiplicity patterns of the final model.

Our results showed significant evidence that 3 diets were associated with lung cancer [odds ratio (OR): 0.271, 95% confidence interval (CI): 0.150-0.488, p = 1.46 × 10^-4, dried fruit; OR: 3.010, 95% CI: 1.608-5.632, p = 5.70 × 10^-4, beer] and SqCLC (OR: 0.135, 95% CI: 0.062-0.293, p = 2.33 × 10^-5, dried fruit; OR: 0.485, 95% CI: 0.328-0.717, p = 2.9 × 10^-4, cheese). There were also suggestive correlations between 5 dietary intakes and lung cancer (OR: 0.441, 95% CI: 0.250-0.778, p = 0.008, cereal; OR: 2.267, 95% CI: 1.126-4.564, p = 0.022, beef), LA (OR: 0.494, 95% CI: 0.285-0.858, p = 0.012, dried fruit; OR: 3.536, 95% CI: 1.546-8.085, p = 0.003, beer) and SCLC (OR: 0.006, 95% CI: 0.000-0.222, p = 0.039, non-oily fish; OR: 0.239, 95% CI: 0.086-0.664, p = 0.006, dried fruit). No other association between diet and lung cancer was observed.

Our study preliminary found that cheese, dried fruit, and beer intake were significantly associated with the risk of lung cancer or its subtypes, while cereal, beef, and non-oily fish intake were suggestively associated with the risk of lung cancer or its subtypes. Well-designed prospective studies are still needed to confirm our findings in the future.