"A study by Harvard researchers says there is a more definite link than previously thought between mold in the home and the risk of severe asthma.

The study, which was published in the American Journal of Respiratory and Critical Care Medicine, concluded that individuals with certain genes were more likely to suffer serious asthma attacks in homes with high amounts of mold.

The researchers studied data from the Childhood Asthma Management Program, looking at children ages 5 to 12 with moderate to persistent asthma. They found 395 children and their parents who had certain expressions of chitinases, which are enzymes that break down the cell wall of fungus, known as chitin.

The scientists then classified the home environments of the subjects based on whether they had more or less than 25,000 mold colonies per gram of household dust. They found that 24% of their subjects lived in high-mold residences.

In homes with high amounts of mold, the researchers found "severe exacerbation of asthma that often included emergency room visits and hospitalization and appeared to be directly linked to the genetic expression of the chitinases enzymes."

The Environmental Protection Agency (EPA) has long listed mold as one of the key asthma triggers in the indoor environment, along with secondhand smoke, dust mites, and cockroaches and other pests.

The Harvard study, however, seems to show a more precise link than had been previously found."...