Effect of environmental molds on risk of death from asthma during the pollen season

Objective: Many studies have noted an association of ambient aeroallergen levels with exacerbation of asthma. This study was undertaken to examine the relationship of aeroallergen levels with asthma-related mortality in Chicago. Methods: The association of environmental aeroallergen levels with death caused by asthma among 5- to 34-year-olds in Chicago was examined for the period of 1985 through 1989. Logistic regression analysis was used to compare the probability of a death caused by asthma occurring on the basis of environmental tree, grass, or ragweed pollen and mold spore levels. Results: Mean mold spore levels but not tree, grass, or ragweed pollen levels were significantly higher for days on which asthma-related death occurred than for days on which no deaths occurred (z = 2.80, p < 0.005). The odds of a death caused by asthma occurring on days with mold spore counts of 1000 spores per cubic meter or greater was 2.16 times higher (95% confidence interval = 1.31, 3.56, p = 0.003) than on days on which mold spore counts were less than 1000 spores per cubic meter. The association with mold spore levels remained significant on multivariate logistic regression with mold spore counts measured as a continuous variable and controlling for pollens, with the odds of an asthma-related death occurring being 1.2 times higher (95% confidence interval = 1.07-1.34) for every increase of 1000 spores per cubic meter in daily mold spore levels. Conclusion: Although death caused by asthma also involves personal, social, and medical access factors, these data suggest that exposure to environmental molds may play a role in asthma-related mortality and should be considered in prevention strategies. (J A LLERGY C LIN I MMUNOL 1995;95:955-61.)