Household mold as a predictor of asthma risk: Recent progress, limitations, and future directions

Abstract

Editorial Household mold as a predictor of asthma risk: Recent progress, limitations, and future directions Nathan Rabinovitch, MD, MPH Denver, Colo Key words: Asthma, children, mold, remediation Asthma prevalence in the United States increased dramatically from 1980 through 1997 and has continued to increase, albeit at a slower pace, over the past decade.1 Some have speculated that this upward trend is, at least in part, related to modern housing con- struction, which tends to increase indoor exposures. Installation of central heating systems and highly insulated windows has been shown to decrease air-exchange rates, increase indoor tem- perature and absolute humidity, and increase levels of mold in car- pet dust.2 The presence of mold spores in the indoor environment is not in itself a problem when the source is the normal inter- change of outside air and when the amount and types of spores in- side are the same or less than outside. However, in the setting of inadequate or poorly maintained ventilation systems that might not provide enough air for dilution or dehumidification and the presence of water in materials or condensation from high humid- ity, mold can actively grow on indoor substrates, potentially add- ing unhealthy chemicals and bioaerosols to the indoor air.3 There is now a fairly robust body of evidence suggesting that living in moldy households increases the risk of childhood asthma. Early cross-sectional and case-control studies had reported an association between asthma development and house- hold moldiness crudely measured by identifying moldy odors or signs of water damage in homes. Investigators from the Cincin- nati Childhood Asthma and Air Pollution Study have strength- ened the evidence for causation in a series of articles that have observed significant relationships between mold levels collected in household dust during infancy and subsequent development of recurrent wheeze and asthma at 1,4 3,5 and 76 years of age. The prospective design of

Symptom Clusters