It's good for a pregnant woman to get lots of sunshine.

Saturday Nov 22, 2008 (foodconsumer.org) -- Your birthday may decide your risk of asthma, according to a new study led by Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University School of Medicine in Nashville, Tenn. .

The study in the Dec 2008 issue of the American Journal of Respiratory and Critical Care Medicine found babies born in autumn, 4 months before the peak of winter virus season, were 30 percent more likely to acquire asthma.

The researchers speculated that winter viruses like respiratory syncytial virus or RSV may be the culprit for the elevated risk of asthma and suggested that preventing these viruses could prevent asthma.

Indeed, many viruses particularly rhinovirus have already been linked to asthma including its inception, exacerbation and possibly severity, according to a study published in the Oct 2008 issue of the Journal of Allergy and Clinical Immunology.

For the current study, Hartert and team followed up more than 95,000 infants born between 1995 and 2000 under the Tennessee Medicaid program from birth through early childhood to examine whether the timing of birth and seasonality of winter virus was associated with the development of asthma.

They found that babies born in the fall or autumn, which is about four months before the peak of the winter virus season, had a 29 percent increased risk of asthma.

The speculation as to what causes the elevated risk of asthma is not new.  

A study led by Jackson DJ and colleagues from the University of Wisconsin-Madison and published in the Oct 2008 issue of American Journal of Respiratory and Critical Care Medicine has already shown that RSV was strongly associated with asthma symptoms like wheezing.

Kackson et al. found "from birth to age 3 years, wheezing with respiratory syncytial virus (RSV) (odds ratio [OR], 2.6), rhinovirus (RV) (OR, 9.8), or both RV and RSV (OR , 10) was associated with increased asthma risk at age 6 years.

Hartert was cited as saying that parents should practice good hygiene and take infection-control measures such as washing their hands frequently to prevent viral infections and the development of asthma in their babies.  But a health observer suggests that other measures can be taken to prevent the viruses.