Delivery in Autumn? Beware of asthma

United States, November 22: Babies born in autumn have about 30 percent increased risk of asthma, according to a recent study published in the first December issue of the American Journal of Respiratory and Critical Care Medicine.

Senior author Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University School of Medicine in Nashville, Tennessee, said, "Children in the Northern hemisphere born in the fall months have the highest rates of asthma, which suggests that winter viruses, like RSV, cause asthma.”

According to Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital in Detroit, it is not clear whether Respiratory Syncytial Virus (RSV) and other viruses actually cause asthma, or whether children who are predisposed to asthma are the ones most likely to get such viruses.

The current study, which involved more than 95,000 infants born between 1995 and 2000, set about examining this aspect. The infants, all part of the Tennessee Medicaid program, were followed from birth through early childhood to determine whether the timing of birth in relation to winter virus season had any tangible impact on the development of asthma.

The results, where fall-born babies were found to be about 30 per cent more susceptible, bear out Hartert’s views that the winter virus season for these babies tends to coincide with a vulnerable period of development, when they are switching over from maternal antibodies to their own.

RSV is a very common infection; about 70 percent of U.S. infants contract RSV infection in the first year. It is unique among viruses as the human body does not ever develop antibodies against it.

Emphasizing the importance of reining in RSV, Hartert said that the next step would be to prove that asthma prevention was possible with stopping the viruses. She expressed hope that “this study's findings will generate heightened interest in development of an RSV vaccine.”

The number of children in the United States with asthma has more than doubled since the 1980s. According to the CDC estimates, about 20 million Americans have asthma, including 9 million children.

Asthma is a chronic disease in which the air passages of the respiratory system get constricted, become inflamed, and are blocked by mucus deposits. Exposure to an environmental stimulant like an allergen, tobacco smoke, perfume or sometimes emotional stress triggers asthmatic attacks. There is no cure for the disease, though it can be kept under control through medication.