I can’t recall at all what I was doing on the day in 1990 that I came down with appendicitis, but as I was training for a marathon at the time, perhaps I spent the morning on a long outdoor run.
And perhaps on that date Minneapolis was having a bad air day.
OK. I have no idea if either of those perhapses is true. But that particular confluence of events would fit the curious new finding, reported earlier this month in the Canadian Medical Association Journal, that some cases of appendicitis in adults may be triggered by short-term exposure to air pollution.
That’s right. Air pollution.
Actually, when you examine historical medical records, the study’s results begin to make sense (and explain why the study was undertaken). Records show that the incidence of appendicitis in industrialized countries skyrocketed during the 19th and early 20th centuries, only to fall in the middle and latter part of the 20th century — coincidentally after the passage of laws aimed an improving air quality.
The United States, for example, saw a 14.6 percent drop in the incidence of appendicitis during the 14 years after passage of the 1970 Clean Air Act.
Also, appendicitis is less common in developing countries. But as those countries become industrialized, the incidence of the illness begins to climb.
For the current study, a team of Canadian researchers looked at data on more than 5,000 adults admitted to hospitals with appendicitis in Calgary between Apr. 1, 1999 and Dec. 31, 2006. They also examined the city’s air-pollution data for that same time period.
They found that the incidence of appendicitis was “significantly” higher when the levels of two particular air pollutants — nitrogen dioxide and ozone — rose. They also found that this association was greatest during the summer.
“The significant associations that we observed in the summer were likely due to increased exposure to air pollutants from spending more time outdoors and leaving windows open,” the researchers wrote.
Air pollution may also help explain why more men than women develop the illness. “Men may be more susceptible to the effects of outdoor air pollution because they are more likely to be employed in outdoor occupations,” the authors of the study suggest.
How would air pollutants harm the appendix (the small organ attached to the large intestine that looks sort of like a worm and has no known function)? The study’s authors suggest that pollutants may either set off an inflammatory response and/or somehow make it easier for bacteria to invade the gastrointestinal tract.
The study has several limitations — particularly the fact that up to 20 percent of people with appendicitis fail to correctly identify their symptoms and thus delay getting medical help. (Most people think they just have some kind of gastrointestinal upset.) So determining what the level of air pollutants was when they got sick is, well, tricky. And the study, of course, could not determine air pollution exposure for individuals.
Furthermore, the study reveals only an association between air pollutants and appendicitis, not a cause-and-effect relationship.
Still, the finding is intriguing.
Don’t let it keep you from your run today, though.