As noted in prior posts, air pollution of various sorts (e.g., particulates, ozone) has been associated with an increased risk of (a) cardiovascular events such as arrhythmia, heart attack, and stroke, (b) asthma and bronchitis in susceptible individuals, and (c) the incidence of certain cancers. Recently published research now notes an association with ear infections and appendicitis.
In a Canadian study, the researchers identified 5,191 adults who had been admitted to hospital with appendicitis between 4/1/99 and 12/31/06. The air pollutants studied in the analysis were ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, and suspended particulate matter of less than 10 µ and less than 2.5 µ in diameter. The researchers estimated the odds of appendicitis relative to short-term increases in concentrations of selected pollutants, alone and in combination, after controlling for temperature and relative humidity as well as the effects of age, sex, and season. The research suggests some association between certain air pollutants and an increased incidence of appendicitis; the research also shows an apparent lag time between an increased in pollution and the increase in hospital admissions for appendicitis. The statistical association was more pronounced amongst men than women. As the authors note: “We found that the incidence of appendicitis was significantly associated with short-term exposure to air pollution. The effect of air pollution was greatest in the summer months, when individuals were most likely to be outside and exposure estimates from fixed-site monitors better reflected an individual’s exposure. In the double-pollutant models, we found that exposure to ozone and nitrogen dioxide was the primary risk factor in the summer. Our findings are robust because the study was population-based, was well powered and used a validated case definition. Also, we controlled for potential confounders through the use of a case–crossover study design, adjusted for meteorologic effects and selected referent time intervals using a time- stratified approach. If our findings are substantiated, this novel association may in part explain the trends in the incidence of appendicitis in industrialized nations.” The authors recognize that conformational studies need to be performed to validate their findings.
One can speculate that, like other more well known adverse human health effects that have been associated with air pollution, inflammatory processes may be the underlying causal connection.
The ear infection association arises from a study presented at the 2009 American Academy of Otolaryngology-Head and Neck Surgery Foundation in San Diego. It analyzed U.S. data on 126,060 children (average age 9 years) from 1997 to 2007, looking at how many instances of ear infections occurred in a one-year period. The researchers used air quality data from the EPA for the same period, focusing on air pollutants such as carbon monoxide, nitrous dioxide, sulfur dioxide, and particulate matter. The researchers reported that frequent otitis media, defined as three or more ear infections in a 12-month period, decreased as air quality improved, as measured by the EPA. The researchers also looked for an association between air quality and respiratory allergy, but found none.