No increased risk of heart disease for Walkerton E.coli patients

A new study shows that people who become ill during the large E.coli outbreak in Walkerton, Ontario have no elevated risk of heart disease or stroke after ten years. The study involved 898 adults who had consumed drinking water that was polluted by cow manure in Walkerton in May 2000. At that time more than 2,300 people fell ill with severe gastroenteritis and seven died.

In conducting the study, researchers linked data from the Walkerton Health Study to large healthcare databases in the province of Ontario. "We found that the 10-year risk for cardiovascular disease was not higher among adults who had severe gastroenteritis during an E.coli outbreak," says Dr. Amit Garg of Lawson Health Research Institute, one of the study's co-authors. "Although we definitely want to avoid anyone getting infected in the first place, this new information is reassuring for those who develop an infection from E.coli." Dr Garg is a scientist at Lawson, a kidney specialist at London Health Sciences Centre, and a professor of Medicine and Epidemiology at Western University's Schulich School of Medicine & Denitstry.

The first author on the paper was Patricia Hizo-Abes, who participated in Schulich Medicine & Dentistry's summer research training program for two summers during medical school.

The E.coli bacterium was the major cause of illness during the large Walkerton E.coli outbreak. In the United States there are 63,000 infections each year, with 12 major outbreaks since 2006. This bacterium is notorious for damaging the kidneys and can cause high blood pressure. Thus there is a concern that people infected by E.coli may be at risk of heart attacks and strokes years later.

It is possible that close scrutiny of people in Walkerton by community physicians and visiting health care professionals may have helped prevent heart disease. These efforts included screening and extra care for hypertension and kidney disease. Prescriptions for hypertension medications increased 8-fold among participants from Walkerton compared with a 3-fold rise among people in nearby communities.

For a full list of all the study authors and their affiliations, please see the full study at http://www.cmaj.ca.