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University of Iowa News Release

March 3, 2004

UI Study Finds High Prevalence Of Asthma Among Rural Iowa Children

The prevalence of childhood asthma in two rural Iowa counties rivals that in large Midwestern cities, casting doubt on the theory that living in a rural environment has a protective effect against developing asthma, according to a new study by University of Iowa researchers.

The study, led by Elizabeth Chrischilles (left), Ph.D., professor of epidemiology in the UI College of Public Health, appeared in the January 2004 issue of the Journal of Allergy and Clinical Immunology.

"There is an impression that people living in rural environments are at less risk for respiratory problems, but previous investigations have had conflicting findings," Chrischilles said. "Some studies suggest a lower frequency of asthma among children who live on farms, while other studies among farmers find farming to be a consistent risk factor for occupational asthma."

Using a standardized questionnaire, the UI research team collected data to measure the frequency and severity of childhood asthma in Keokuk and Louisa counties in southeastern Iowa, and to estimate whether children who live on farms had different outcomes than did their non-farm schoolmates from the same rural areas. The study population consisted of nearly 3,100 children, ages 6 to 14 years old, enrolled in 10 school districts from 2000 to 2002.

"We found that the prevalence of asthma in these two counties was comparable with that of inner-city schools in Minneapolis, Chicago and Seattle and higher than that observed in rural Canada and Europe," Chrischilles said. "Also, among those children with asthma, the severity was about the same for both farm and non-farm residents. These results indicate that living in a rural environment is not protective for asthma."

The researchers also noted that asthma is likely under-diagnosed in the two counties. Of the 14 percent of parents who reported that their child had frequent respiratory symptoms, less than half (42 percent) reported that their child had ever been given a physician diagnosis of asthma.

"This finding and those of other studies suggest that under-diagnosis of asthma is common," Chrischilles said.

"Given the high rate of frequent and severe asthma symptoms among children in this study, developing effective rural screening programs to detect asthma and improve asthma diagnosis and management are important health care priorities," said senior author James Merchant, M.D., Dr.P.H., professor and dean of the UI College of Public Health.

The research team also included Richard Ahrens, M.D., professor of pediatrics in the UI Roy J. and Lucille A. Carver College of Medicine; and UI College of Public Health investigators Angela Kuehl, Pharm.D.; Kevin Kelly, Ph.D.; Peter Thorne, Ph.D., and Leon Burmeister, Ph.D.

The study was supported by a grant jointly funded by the National Institute of Environmental Health Sciences and the Environmental Protection Agency.

STORY SOURCE: University of Iowa College of Public Health Office of Communications, 4257 Westlawn, Iowa City, Iowa 52242.

CONTACT(S): Media: Debra Venzke, 319-335-9647,

PHOTOS: Elizabeth Chrischilles; James Merchant