WEDNESDAY, Sept. 26 (HealthDay News) -- Infants in urban areas have different patterns of viral respiratory illness than those in the suburbs, which may explain why inner-city children are more likely to develop asthma, a new study suggests.

The findings may lead to new ways to treat childhood asthma, according to Dr. James Gern of the University of Wisconsin, Madison, and colleagues.

Previous studies have linked viral respiratory illnesses to the development of asthma in children and have shown that children with human rhinovirus infections are more likely to develop asthma by age 6 than those with respiratory syncytial virus infections.

In this study, researchers analyzed nasal secretions from 500 infants living in inner-city areas of Boston, Baltimore, New York City and St. Louis, and 285 infants from suburban Madison, Wis. The samples were taken while the children were healthy, and also when they had respiratory illnesses.

Inner-city infants had lower rates of human rhinovirus and respiratory syncytial virus than suburban infants, but were more likely to test positive for adenovirus infections -- 4.8 percent of urban babies tested positive for adenovirus only versus 0.7 percent of suburban babies.

Adenovirus can cause persistent infections and the researchers suggested that adenovirus infections early in life could alter the development of the lungs or airways. The investigators plan to follow the inner-city kids for at least 10 years to determine whether adenovirus infections are associated with increased rates of asthma and lower levels of lung function.

The study was published online Sept. 26 in the Journal of Infectious Diseases.

More information

The American Lung Association has more about children and asthma.