FRIDAY, Aug. 5 (HealthDay News) -- Exposure to household mold in infancy greatly increases a child's risk of developing asthma, a new study says.

Researchers analyzed seven years of data collected from 176 children who were followed from infancy as part of the Cincinnati Childhood Allergy and Air Pollution Study. The children were considered at high risk of developing asthma because of family medical history.

By age 7, 18 percent of the children developed asthma.

Children who lived in homes with mold during infancy were three times more likely to develop asthma by age 7 than those who weren't exposed to mold when they were infants.

"Early life exposure to mold seems to play a critical role in childhood asthma development," lead author Tiina Reponen, a professor of environmental health at the University of Cincinnati, said in a university news release. "Genetic factors are also important to consider in asthma risk, since infants whose parents have an allergy or asthma are at the greatest risk of developing asthma."

"This study should motivate expectant parents, especially if they have a family history of allergy or asthma, to correct water damage and reduce the mold burden in their homes to protect the respiratory health of their children," Reponen added.

The study appears in the August issue of the journal Annals of Allergy, Asthma & Immunology.

Overall, about 9 percent of school-aged children in the United States develop asthma, but research has shown that rates are higher among children in poor, urban families.

More information

The American Lung Association has more about children and asthma.