September 2012

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Household Mold Linked to Asthma in Children

Three types of mold were more common in the homes of babies who later developed asthma. The finding highlights how important it is to prevent water damage and mold growth in homes with infants.

Asthma affects more than 6 million children nationwide. Previous studies have linked childhood asthma to indoor mold, which can thrive in homes with moisture problems. The connection between mold and asthma, however, is complicated and not fully understood. Asthma is often associated with allergies, and molds release tiny particles into the air that can cause allergic reactions.

To learn more about the link between mold and childhood asthma, researchers visited the homes of nearly 300 infants who were about 8 months old. The scientists looked and smelled for evidence of mold. They also measured levels of 36 different types of mold in dust samples from each home.

Once the kids reached age 7, the researchers found, nearly 1 in 4 had developed asthma. The risk of asthma was greater for kids whose original homes had higher “mold scores.”

Three particular species of mold were most associated with asthma. These species—Aspergillus ochraceus, Aspergillus unguis and Penicillium variabile—are common to water-damaged buildings.

Sometimes homes that at first seemed to have no mold had high mold scores according to the dust sample analyses. Other studies have found that many homes with high mold scores have undetected mold problems. Fixing these problems can improve asthma in children.

The link between the 3 molds and asthma doesn’t prove that the molds cause asthma on their own. But it does provide evidence that indoor mold can contribute to the development of asthma.

“Previous scientific studies have linked mold to worsening asthma symptoms, but the relevant mold species and their concentrations were unknown,” says lead researcher Dr. Tiina Reponen of the University of Cincinnati. Preventing home water damage and growth of these molds might help relieve some problems with asthma.