Joe Paraskevas | The Winnipeg Free Press

Heavy pesticide use in parts of rural Manitoba could be putting all residents in those areas -- not only farmers -- at increased risk of serious medical problems, a recent university study has found.

Rural residents could stand a greater chance of bearing children with physical abnormalities or severe birth defects if they live in areas of higher-than-average pesticide spraying, according to research by a University of Manitoba student.

Moreover, residents young and old of such areas could also be at greater risk of eye disorders.

The study is believed to among the first anywhere in the world to sift through thousands of case records of medical visits as well as databases of pesticide use in order to find possible connections.

The study's author stopped short of drawing a direct link between agricultural chemicals and birth defects. Too many factors exist that can govern a person's health to be able to draw such cause-and-effect conclusions, even in a study of considerable scope, said Jennifer Magoon, a U of M graduate student.

Still, in an interview, Magoon called her findings statistically significant. The higher incidence of birth-related abnormalities or adult disorders in parts of the province where pesticides are used heavily isn't simply coincidence, she said.

And others are hailing her work for its sweeping examination of rural Manitoba pesticide use -- including insecticides, herbicides and fungicides - an-- its possible tie to the health of thousands of the province's residents.

"We found significant associations with insecticides," said Magoon, who conducted the research as part of her master's degree in community health sciences.

"There were also some associations with overall pesticide use, but it was really insecticides that were what stood out. This is a cross-sectional study, so we can't know cause and effect. We just know that in areas of higher insecticide use you see higher amounts of these (adverse) health outcomes."

Manitoba has a detailed and far-reaching database of public health records -- with patients' names removed -- said Dr. Patricia Martens, director of the Manitoba Centre for Health Policy, and Magoon's thesis adviser.

The richness of the health records offered the opportunity for a wide-ranging study.

"Often studies are done on a particular people like, let's say, the group of farmers who have direct contact with pesticides," Martens said. "This study was looking at the entire population."

The province also has one of the world's most comprehensive agricultural databases with information on pesticide use, Martens added.

"We have a huge variety in Manitoba of places that are heavy users of some pesticides because they go into very intensive crop production of specialty crops, and some areas that use very little pesticides because they're growing pasture or something like that," she said. "So combining the two is a very powerful study."

Magoon blended the two databases, looking at the years 2001 to 2004. She studied 323,368 health records that included physician claims, hospital separations and pharmaceutical files for residents of much of rural southern Manitoba.

She found that male babies in an area with average insecticide use had a 32.7 per cent chance of having abnormal conditions such as higher- or lower-than-average birth weight, respiratory ailments or jaundice. Female babies had a 30.4 per cent chance.

In areas where double that amount of insecticide was used, the chance of such anomalies increased four percentage points for baby boys and 3.5 percentage points for girls.

Magoon also found that in areas where pesticide use was double the provincial average, cases of mild and severe birth defects in boys rose from 11.8 per cent to 12.8 per cent.

Eye disorders among children and adults alike rose from 34 per cent when pesticide use was at an average level to 35.7 per cent when pesticide use doubled.

Insecticide use, which rendered the clearest results in Magoon's study, are highest in Manitoba's southwest corner, in an area east of Brandon, as well as in an area just west of the Red River.

Insecticides are often used in potato farming in that area in central southern Manitoba. Insecticides are used on spring wheat and also on canola crops in the province's southwest.

Magoon found the results of her work worrisome, but she and Martens were quick to add that the data alone didn't make a direct connection between pesticides and public health.

One rural public health official familiar with Magoon's research came to a similar conclusion, but said the study did continue the work of understanding how chemicals might be adversely connected to rural life.

"I wouldn't say that it's going to implicate concisely that pesticides are related to these illness or the outcomes that they said. But what it does help me to see is the linking of databases," said Dr. Shelley Buchan, medical officer of health for Regional Health Authority -- Central Manitoba Inc.

"To be able to link health information with some of the environmental information and be able to see, are there any trends that we're seeing, which can't really be done easily other ways, this is very valuable," Buchan added.