Optimizing mold exposure assessment in asthma research

The main objective of this study is to identify an optimum mold exposure assessment method that is applicable to an epidemiologic study of the development of allergic disease and asthma. Homes of 75 children were assessed for mold by visual observations, dust sampling, and air sampling. Samples were analyzed for endotoxin, (1-3)-β-D-glucan, and fungal spores. The Mold Specific Quantitative Polymerase Chain Reaction was used to analyze 36 mold species in the dust samples, and the Environmental Relative Moldiness Index (ERMI) was calculated. Homes were classified to three categories based on visual observations (Class 0: no mold, Class 1: low mold, Class 2: high mold) and into two categories based on ERMI (<5 = low and >5 = high). When visible mold categories were used, concentrations were generally lowest in Class 0, except for endotoxin, which was highest in this category. Concentrations of endotoxin, (1-3)-β-D-glucan, and fungal spores were consistently higher in homes with high ERMI compared to those with low ERMI. Future analysis will indicate which, if any, of the assessment methods is associated with the development of asthma.