Environmental Risk Factors and Appendicitis Incidence: A Pooled Up Analysis

Purpose The purpose of this study was to analyze whether environment risk factors had an impact on appendicitis incidence. Methods This study investigated the association between environmental risk factors and the incidence of appendicitis through a meta-analysis. Through searching in four databases (PubMed, Cochrane, Web of Science and Embase) up to May 2025 for cohort studies assessing the association between environment risk factors and appendicitis incidence. After study selection, a total of eight studies from five countries were included in the meta-analysis. Random-effect model was employed in the study, I ² statistic assessed heterogeneity, and the Egger's test detected publication bias. Results A total of eight studies including 346304 appendicitis patients were included in this study. Analysis of overall odds ratio (OR) of appendicitis incidence associated with environment risk factors was estimated to be statistic significant (OR = 1.06, 95% CI 1.03–1.09). Further subgroup analysis showed that elevated temperature, PM₁₀, ozone (O₃), and nitrogen dioxide (NO₂) were significantly associated with an increased risk of appendicitis. Specifically, each unit rise in temperature was linked to a 7% higher risk (OR = 1.07, 95% CI 1.02–1.12), while increases in PM₁₀, O₃, and NO₂ were associated with 4% (OR = 1.04, 95% CI 1.01–1.07), 8% (OR = 1.08, 95% CI 1.06–1.11), and 13% (OR = 1.13, 95% CI 1.06–1.20) elevated risks, respectively. Notably, NO₂ exhibited the strongest effect. These findings suggest that environmental factors, particularly air pollutants and high temperature, may contribute to a higher incidence of appendicitis. Conclusion We found that the high temperature, O ₃ , NO ₂ and PM ₁₀ was associated with high incidence of appendicitis.