Evaporative (swamp) coolers are not associated with house dust mite or mold sensitization in a large pediatric cohort in Colorado
Sunday, March 4, 2018: 2:45 PM
S230EF (Convention Center)
Neema Izadi, MD MS, ,
RATIONALE: House dust mite (HDM) growth requires a minimum relative humidity of greater than 55-75% at 15-35 degrees Celsius. Evaporative (or swamp) coolers (EC) have been shown to raise humidity in homes by about 10%. Small studies have suggested that HDM and mold sensitization is associated with EC use. This study evaluated whether EC use in an arid environment leads to HDM and/or mold sensitization.

METHODS: Retrospective review of all Colorado residents younger than 21 years of age from 2008 to 2017 seen at National Jewish Health who had at least one positive environmental skin prick test (SPT), and either HDM and/or mold SPT performed were analyzed for whether they had an EC, atopic dermatitis, HDM sensitization, and mold sensitization. Sensitization was based on a positive SPT defined as a wheal of >3mm above the saline control.

RESULTS: Sensitization to both HDM (n=8,503) and mold (n=9,286) is not associated with EC use with relative risk 1.01 (95% CI 0.91 to 1.12) p=0.85, and relative risk 1.03 (95% CI 0.96 to 1.10) p=0.43 respectively. This result held true when stratifying for gender, varying age groups, atopic dermatitis status, each individual mold, and combinations of varying mold characteristics (indoor, temperate, and water damage-associated).

CONCLUSIONS: ECs can raise the relative humidity of homes in arid environments, and have previously been shown in small studies to be associated with HDM and/or mold sensitization. However, in a very large cohort of atopic children living in Colorado, there is no increased risk for HDM or mold sensitization with EC use.