Looking back at historical data, more than a few scientists have noticed an interesting trend—during surges in industrialization, there appeared to be corresponding jumps in appendicitis cases. With the growth of industry in North America and Europe during the 1800s and early 1900s came the increased emission of pollutants such as ozone, nitrogen dioxide and carbon monoxide. And as more of these harmful particles were released into the air, there was also an increase in cases of appendicitis. As clean air legislation emerged in the late 1900s, there was a noticeable drop in appendicitis. The authors of a new study published in the Canadian Medical Association Journal, offer several examples of this correlation, including the fact that “…after the United States’ Clean Air Act was passed in 1970, the incidence of appendicitis decreased by 14.6% from 1970 to 1984.” That the trends seemed to fit together prompted a team of scientists from health agencies and universities across Canada to delve back into a subject that others had previously explored with inconclusive results—was pollution actually contributing to the rate of appendicitis, or was it just a coincidence?
To test the hypothesis that pollution might be to blame, the researchers looked back over records for 5,191 adults who had been treated for appendicitis between 1999 and 2006. They then did a detailed assessment of rates of pollution, measuring the concentration of fine particles in the air and then determining patients’ levels of exposure the day they were admitted to the hospital, a day before, and three, five and seven days before suffering from appendicitis. Their results suggest that the correlation between pollution rates and appendicitis may not just be a coincidence.
As the authors summarize, “We found that the incidence of appendicitis was significantly associated with short-term exposure to air pollution.” Across the board, the researchers found that high levels of sulfur dioxide and ozone were associated with increased risk for appendicitis, but within the results there was some variation on how different pollutants impacted different slices of the population—younger people, ages 18 to 34, were more likely to suffer from appendicitis on days when ozone concentrations were particularly high, for example. They also found that the association between increased risk for appendicitis and density of air pollutants was most significant during the summer months, a trend they say might be caused by increased exposure to pollution as people spend more time outside, or with the windows open.
Of course, this research is very preliminary, and the authors concede that prior studies into the relationship between appendicitis and pollution haven’t substantiated any link, and that their study had several limitations—it didn’t take children into account, for example, and the data doesn’t account for patients who may have delayed the trip to the hospital, meaning the actual onset of appendicitis was earlier than the records showed. Yet, they also point out that unlike previous research their more specific diagnostic criteria limited inclusion of false cases of appendicitis, resulting in higher quality data. And unlike past studies, they were careful to assess average cumulative exposure to pollutants, they point out.
If these findings are duplicated and verified, however, they could give doctors a new understanding of what drives appendicitis—and, of course, give medical authorities yet another reason why improving air quality is a public health boon.