Risk Factors for Childhood Asthma

By Linda Schultz, D.V.M., Ph.D., Ivanhoe Health Correspondent

LOS ANGELES (Ivanhoe Newswire) -- Infants exposed to cockroaches, herbicides, pesticides, farm crops, dust or animals have a higher risk of developing asthma, according to researchers presenting at the 99th International Conference of the American Thoracic Society.

To investigate associations between early life exposures and asthma, Dr. Frank Gilliland and colleagues from the University of Southern California conducted a case-control study of children who developed asthma by age 5 and compared these children to asthma-free children. Parents were asked to provide information on early life exposures through interviews. Researchers compiled the data and used conditional logistic regression analysis.

Dr. Gilliland reports children had an increased risk of asthma if they were exposed within the first year of life, but not at older ages, to cockroaches, herbicides, pesticides, farms crops, dust or animals. Exposure to wood smoke, soot or exhaust anytime between birth and age 5 was also associated with a higher risk of asthma.

Interestingly, the risk of early asthma decreased the more siblings the children had when they were born. This is in contrast to data showing that daycare attendance before 4 months of age increases risk of early asthma. “It’s a finding we can’t explain yet,” says Dr. Gilliland. Breast-feeding exclusively or early exposure to pets were not found in this study to protect children from getting asthma.

Dr. Gilliland concludes, “Environmental exposures may be an important determinant of childhood asthma and the first year of life may be a critical window for these exposures.”

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