A University of Iowa study released Thursday said children living on hog farms are more likely to have asthma. The prevalence of asthma is even more dramatic among children living on hog farms where antibiotics are added to feed, said the study’s author Dr. James A. Merchant, dean of the College of Public Health and an environmental health professor.

Researchers examined 644 children from birth through 17 years old living in Keokuk County. They considered other risk factors for asthma including premature birth, respiratory infections at a young age, personal history of allergies and family history of allergic disease.

The study indicated that 55.8 percent of children living on hog farms where antibiotics are added to feed had at least one health indicator of asthma. That compares to 26.2 percent of children on farms that do not raise hogs.

“We believe that some of the increase in asthma risk is related to occupational and bystander exposures in animal feeding operations,” Merchant said.

Farms which provide antibiotics in pig feed tend to be larger, but Merchant said the research team concluded antibiotic exposure may play some role in the development of childhood asthma.

“We’re quite certain that the kids who were working in or as bystanders or close to those facilities are getting exposed to antibiotic laden dust,” Merchant said.

He said further study needs to be done to determine what role the antibiotics in feed plays.

The study indicated that 42.9 percent of children on farms with less than 500 pigs had signs of asthma while 46 percent on farms with more than 500 pigs had asthma indicators.

The study indicated that 33.6 percent of children not living on a farm and not around swine had at least one indicator of asthma.

Merchant acknowledged that asthma is a complex condition that may be caused by several genetic and environmental factors, but said the study should heighten the awareness of swine farm parents that their children may face an increased risk of asthma, he said.

He said farm families should limit a child’s exposure to the hog feeding operations and should keep contaminated clothing and shoes out of the house.

Like many hog producers, Rep. Sandra Greiner, R-Keota, said she’s skeptical of studies drawing such connections.

Greiner, her husband and three sons raised hogs in eastern Iowa for decades and developed no adverse health problems.

“From my own personal experience, I raised three children whose job it was to do chores. They had chores to do as little boys and they more or less grew up out there and their health is fine,” she said.

Her children have grown to be farmers and one son continues to raise hogs, she said.

Peggy Birchmeier, who lives on a Van Buren County livestock farm near Milton, believes the study.

Birchmeier said her husband now raises only cattle, but once had a small hog operation. She would be concerned for children exposed to the air.

“They’re little respiratory systems aren’t developed yet to handle it,” she said. “Even as an adult, I would have an air mask on because you have the dust and the particles floating around in the air.”

Merchant said the study was limited to close exposure by children living on the hog farm and does not suggest a higher risk for neighbors living downwind from the farm.

The study was published in the peer-reviewed journal Environmental Health Perspectives, a publication of the National Institute of Environmental Health Sciences.