I t's clear as day -- so to speak -- that air pollution is bad for our health. It has long been linked with respiratory problems including asthma and emphysema, and studies have also associated it with cardiovascular disease. The latest finding by Canadian researchers suggests there may be a link between pollution and appendicitis.

At the University of Calgary, Gilaad G. Kaplan, MD, MPH, and his colleagues studied the records of more than 5,000 adults hospitalized for appendicitis between 1999 and 2005. Next, using figures from Canada's National Air Pollution Surveillance (NAPS) Network, they looked for possible links between the occurrence of appendicitis and daily air levels of ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide and particulate matter pollutants. Investigators found that...

• On days with the highest ozone concentration compared with days of lowest ozone concentration, people were approximately 15% more likely to be hospitalized for appendicitis.

• The impact of air pollution levels was most dramatic in the summer when people spend more time outside. During the summer months, exposure to high concentrations of nitrogen dioxide and ozone were significantly associated with admission to a hospital for appendicitis, even after adjusting for temperature and humidity.

This research was presented at the Annual Scientific Meeting of the American College of Gastroenterology in October 2008.

Earlier research demonstrates that exposure to these sorts of air pollutants may contribute to disease through an increase in inflammation and oxidative stress, causing the formation of free radical molecules. Dr. Kaplan believes that these same mechanisms may bring on appendicitis. Further research is necessary to corroborate this association and to determine the importance of this connection and what short- and long-term effects pollution may have on disease processes, including appendicitis.

What can we do in the meantime? Daily Health News contributing medical editor Andrew L. Rubman, ND, points out that the proper nutrients help the body to defend itself against even insults like smog. "The appendix functions with aid from well-digested, healthy foods that contain a broad range of nutrients and antioxidants. So your best bet is to rely on smart eating and professional oversight to help your natural defenses with multivitamin supplementation."

Beyond that, make sure you follow all the usual advice about avoiding air pollution as much as you reasonably can. You can check local air quality reports daily at airnow.gov.