Department of Medicine, Environmental Health Research Group, Institute of Public Health, University of Calgary, Calgary, Alberta, Canada. ggkaplan@ucalgary.ca
Environmental determinants of appendicitis are poorly understood. Past work suggests that air pollution may increase the risk of appendicitis.
We investigated whether ambient ground-level ozone (O3) concentrations were associated with appendicitis and whether these associations varied between perforated and nonperforated appendicitis.
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 meta-analysis was used to derive a pooled risk estimate. Stratified analyses were used to estimate associations separately for perforated and nonperforated appendicitis.
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).
Higher levels of ambient O3 exposure may increase the risk of perforated appendicitis.
Notes
Cites: J Am Coll Surg. 2006 Mar;202(3):401-616500243
Cites: Am J Med Sci. 2007 Apr;333(4):230-417435417
Cites: Respir Med. 2007 Jun;101(6):1140-617196810
Cites: Ann Surg. 2007 Jun;245(6):886-9217522514
Cites: Ann Intern Med. 2007 Oct 16;147(8):W163-9417938389
Cites: Environ Health. 2007;6:4018157917
Cites: Cardiovasc Ultrasound. 2009;7:3019552797
Cites: CMAJ. 2009 Oct 27;181(9):591-719805497
Cites: Environ Health Perspect. 2010 Jan;118(1):120-420056584
Cites: Surgery. 2010 Mar;147(3):366-7219892382
Cites: BMC Health Serv Res. 2010;10:25020735857
Cites: Arch Surg. 2011 Feb;146(2):156-6121339425
Cites: Part Fibre Toxicol. 2011;8:1921658250
Cites: Am Fam Physician. 1999 Nov 1;60(7):2027-3410569505