Associations between Quantitative Measures of Fungi in Home Floor Dust and Lung Function among Older Adults with Chronic Respiratory Disease: A Pilot Study

Abstract

Objective. Many fungi may cause allergic reactions and increase asthma symptoms prevalence and severity. One susceptible, vulnerable population subgroup of increasing size in industrialized countries and of public health concern who spends the majority of their time at home is older adults. Older adults diagnosed with chronic obstructive pulmonary disease (COPD) are at risk of exposure to fungi. Currently, species identification is based on observation of microscopic and macroscopic morphologies, which may underestimate concentrations compared to quantitative polymerase chain reaction (qPCR)-based measurements which are toxicologically more relevant to exposure science. Methods. This article analyzes quantitative indoor exposure data on fungi in floor dust (cells/cm2 floor) by real-time qPCR-based detection with quantitative outcome data via field spirometry in a pilot community-based study in Visalia, Tulare County, California, between July 2009 and January 2010. Subjects (n = 9, five females, four males) were Caucasian, English-speaking, nonsmoking older adults with doctor-diagnosed asthma and/or COPD. Results. While certain results did not reach statistical significance (p ≤ .10) due to sample size—overall and by gender—we found consistent trends and statistically significant associations for total fungal DNA (summer data) with forced vital capacity and forced expiratory volume in 1 second. Conclusions. The results of this pilot study are novel and suggest adverse effects of exposure inside homes to certain fungal species. This pilot study supports the need for larger prospective epidemiologic studies of older adults with asthma and/or chronic bronchitis based on quantitative environmental and clinical measures.