Parents who are concerned about having a child with asthma may want to consider which month they conceive, a new study suggests.
Children born in the fall months, before the height of cold and flu season, may be more likely to develop childhood asthma than babies born at other times, according to a new study published in the American Journal of Respiratory and Critical Care Medicine.
A team of researchers led by Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University, examined records for more than 95,000 children and their mothers in Tennessee.
They found that risk for childhood asthma was higher for babies who suffered from a respiratory tract infection early in life -- and babies born in the fall months seemed particularly at risk for contracting respiratory viral infections.
Risk was highest for infants born in early fall, approximately four months before the winter peak. The researchers' findings suggested that these babies, who are most likely those conceived in December or January, have a nearly 30 percent greater risk for developing asthma.
"Although it's difficult to influence birth timing, this study suggests that avoiding conceiving these months may have short and long-term benefits," Hartert explained. "Still, we must prove if preventing these respiratory tract infections will prevent a lifetime chronic disease."
The National Heart, Lung and Blood Institute estimates that more than 22 million people in the United States have asthma. Of this figure, nearly 6 million are children.
Though an array of treatments are available to help people live with asthma, in many cases the precise reasons for the development of the condition remain unclear.
Hartert's team suggests that the development of asthma in children could be tied to whether they have suffered a respiratory infection during their first year of life -- particularly since the children in question are born at a time when cold and flu rates are on the rise.
However, the researchers caution that this study does not prove that preventing a respiratory tract infection early in life will also prevent the development of asthma later on.
The other side of the equation is genetics, and doctors say the interplay between a child's natural susceptibility to the condition and the infections they sustain while young could decide their asthma fate.
"It's pretty convincing that [asthma is] due to the [respiratory] virus," said Dr. Elliot Israel, director of clinical research in the Pulmonary Division at Brigham and Women's Hospital in Boston, Mass. "The virus may be responsible for some asthma. If you have a strong family history of asthma, [you] may want to time your birth."
Hartert estimates that your risk for developing asthma is about 40 percent if one parent has asthma, and about 80 percent if both parents have asthma. However, she estimates that contracting a serious viral respiratory infection in early life can increase your chances of developing asthma by about 30 to 40 percent.
Dr. Franklin Adkinson, professor of medicine and associate training program director of the Johns Hopkins University Asthma and Allergy Center, said at the very least, the research could give new parents another reason to keep their babies cold- and flu-free.