"It's speculative, but air pollution might be driving inflammation which triggers appendicitis," he said. "We're a few steps away before we can make that statement. We need to confirm and replicate these findings."
Kaplan and his co-authors plan more studies in multiple cities in Canada.
Last year, Forbes magazine rated Calgary as the world's cleanest city and Baku, Azerbaijan, as the dirtiest.
The U.S. National Institutes of Health has more on appendicitis.
SOURCES: Gilaad G. Kaplan, M.D., assistant professor of medicine, division of gastroenterology, University of Calgary, Alberta; F. Paul Buckley III, M.D., assistant professor of surgery, Texas A&M Health Science Center College of Medicine, and surgeon, Scott & White Healthcare Round Rock, Texas; Oct. 5, 2009, Canadian Medical Association Journal