University Of Tasmania
2 files

Ambient Ozone Concentrations and the Risk of Perforated and Nonperforated Appendicitis: A Multicity Case-Crossover Study

journal contribution
posted on 2023-05-18, 10:51 authored by Kaplan, GG, Tanyingoh, D, Dixon, E, Johnson, M, Amanda WheelerAmanda Wheeler, Myers, RP, Bertazzon, S, Saini, V, Madsen, K, Ghosh, S, Villeneuve, PJ

Background: Environmental determinants of appendicitis are poorly understood. Past work suggests that air pollution may increase the risk of appendicitis.

Objectives: We investigated whether ambient ground-level ozone (O3) concentrations were associated with appendicitis and whether these associations varied between perforated and nonperforated appendicitis.

Methods: We based this time-stratified case-crossover study on 35,811 patients hospitalized with appendicitis from 2004 to 2008 in 12 Canadian cities. Data from a national network of fixed-site monitors were used to calculate daily maximum O3 concentrations for each city. Conditional logistic regression was used to estimate city-specific odds ratios (ORs) relative to an interquartile range (IQR) increase in O3 adjusted for temperature and relative humidity. A random-effects metaanalysis was used to derive a pooled risk estimate. Stratified analyses were used to estimate associations separately for perforated and nonperforated appendicitis.

Results: Overall, a 16-ppb increase in the 7-day cumulative average daily maximum O3 concentration was associated with all appendicitis cases across the 12 cities (pooled OR = 1.07; 95% CI: 1.02, 1.13). The association was stronger among patients presenting with perforated appendicitis for the 7-day average (pooled OR = 1.22; 95% CI: 1.09, 1.36) when compared with the corresponding estimate for nonperforated appendicitis [7-day average (pooled OR = 1.02, 95% CI: 0.95, 1.09)]. Heterogeneity was not statistically significant across cities for either perforated or nonperforated appendicitis (p > 0.20).

Conclusions: Higher levels of ambient O3 exposure may increase the risk of perforated appendicitis.


Publication title

Environmental Health Perspectives










Menzies Institute for Medical Research


Us Dept Health Human Sciences Public Health Science

Place of publication

United States

Rights statement

Copyright unknown

Repository Status

  • Open

Socio-economic Objectives

Public health (excl. specific population health) not elsewhere classified

Usage metrics

    University Of Tasmania