MONDAY, May 20, 2013 (HealthDay News) -- A child whose mother lived near heavy traffic while pregnant faces a relatively higher risk for developing a respiratory infection before the age of 3, a new study suggests.
Researchers looked at data involving nearly 1,300 pairs of mothers and infants from eastern Massachusetts. All the mothers began study participation while in their first trimester of pregnancy at some point between 1999 and 2002.
About 6 percent of the mothers lived within 100 meters (about 110 yards) from a major roadway, while another 7 percent lived between 100 and 200 meters away. About one-third of the mothers lived from 200 to 1,000 meters (about two-fifths of a mile) away, while the rest lived 1,000 meters or more from a major roadway.
Among their infants, about 53 percent had suffered at least one diagnosed respiratory infection, including pneumonia, bronchiolitis or croup by age 3.
Offspring of mothers living the shortest distance from a major roadway had a 1.74 times greater risk for such infections compared to those living farthest away. Those whose mothers lived 100 to 200 meters from a roadway had a 1.49 greater risk.
The findings held true even after adjusting for a range of factors, including maternal smoking during pregnancy, postnatal household smoking, breastfeeding, daycare attendance, presence of other young children in the household and season of birth.
"The connection between in utero and early life cigarette smoke exposure and adverse infant respiratory outcomes is well-established, but the relation of prenatal ambient air pollution to risk of infant respiratory infection is less well-studied," study author Dr. Mary Rice said in an American Thoracic Society news release.
Rice, a pulmonary and critical care fellow at Massachusetts General Hospital and Beth Israel Deaconess Medical Center, and colleagues are scheduled to present their findings this week at an American Thoracic Society meeting in Philadelphia.
Studies presented at medical meetings should be considered preliminary until published in a peer-reviewed journal. The new study found a link between exposure to heavy traffic in pregnancy and respiratory illness in children, but it didn't prove cause-and-effect.
For more on air pollution and infants, visit the March of Dimes.