Correlation between Allergic Rhinitis or Hay Fever and Lung Cancer: A Systematic Review and Meta-Analysis

Abstract

Introduction: The association between allergy and cancer is contradictory, whereas some forms of cancer have inverse associations with allergy. Allergic rhinitis (AR) is the most prevalent form of allergy, and lung cancer is one of the most prevalent forms of cancer, with the highest percentage of mortality. Recent studies report a positive association between asthma and lung cancer, although that, too, is not conclusive yet. However, AR has a positive association with asthma; therefore, our research question was to explore whether there is any correlation between AR and lung cancer epidemiologically. Methods and Results: Seven eligible articles were found to be eligible for this systematic review and meta-analysis, including 4663 cases and 9056 controls, five from the USA and one each from Canada and Germany. Pooled analysis [OR: 0.56; 95% CI: 0.45-0.70; p-value<0.00001], and [RR: 0.63; 95% CI: 0.51-0.77; p-value<0.00001] depicted a strong inverse relationship between AR and lung cancer. Among small-cell and non-small-cell lung cancer, the inverse association was stronger with Small-cell lung cancer (SCLC): [OR: 0.58, 95% CI: 0.46-0.73], and [RR: 0.64, 95% CI: 0.53-0.77], with a p-value <0.00001; however, this finding was only based on one study among females. The study in Canada (OR: 0.35 and RR: 0.38) and in Germany (OR: 0.18 and RR: 0.19) had lower OR and RR values compared to the studies in the USA (OR 0.62 and RR 0.69). However, two studies in Canada and Germany were the outlier studies in our study, and sensitivity analyses reduced the heterogeneity from 64% to 27% (for OR) and 72% to 40% (for RR) while analyses were conducted eliminating those studies. No low-quality studies were obtained. Conclusion: New epidemiological studies are required to observe the current scenario more comprehensively.