TUESDAY, Oct. 12, 2004 (HealthDayNews) -- Children with brothers or sisters have a lower asthma risk than children with no siblings, says a Canadian study in the October issue of the journal Chest.
The researchers tracked 170,960 newborns from birth to age 6. Overall, 14.1 percent of the newborns were seen by a doctor for asthma. The highest incidence of asthma was in the first two years of life.
The study found that children of multiple births and children with siblings had lower asthma risk than children without siblings. Children born from July through December had a greater asthma risk than children born from January through March.
The risk of asthma increased if newborns were male, lived in an urban area, were born premature, had low birth weight, or if their primary-care provider was a pediatrician. A maternal or sibling history of asthma, exposure as an infant to upper or lower respiratory tract infections, and the presence of congenital conditions such as respiratory distress syndrome or cystic fibrosis were other factors that increased asthma risk.
The American Lung Association has more about childhood asthma.