Quantifying Prevalence Ratios for Asthma, Respiratory, and Systemic Symptoms Associated with Dampness and Mold Among School Staff: Interpretation of NIOSH DMAT Scores.

Indoor dampness and mold (D/M) are prevalent and represent a significant exposure linked to adverse health outcomes among building occupants. We analyzed 6,492 room D/M scores collected from 50 schools using the NIOSH D/M Assessment Tool (DMAT) to quantify the association between D/M exposure and health outcomes, including self-reported physician-diagnosed asthma, and respiratory and non-respiratory symptoms, among 1,529 school staff. Prevalence ratios and 90% confidence intervals were estimated via logistic regression with conditional standardization and the delta method. Generalized additive models showed approximately log-linear exposure-response relationships for most outcomes, with statistically significant but slight nonlinearity detected for shortness-of-breath (SOB) attacks, coughing attacks, and building-related dizziness/lightheadedness. Under this log-linear specification, each one-unit increase in DMAT score was associated with a 7-12% increase in the prevalence of asthma and respiratory symptoms, including wheeze, SOB, cough, and stuffy/itchy nose, and with a 6-16% increase in systemic symptoms, including difficulty remembering, confusion, and dizziness/light headedness, and headache, at α=0.10. A DMAT score of 2.0 was estimated as a preliminary score for increased surveillance, based on an assumed log-linear exposure-response relationship for post-hire onset asthma, its observed prevalence, and DMAT score distribution in the schools. Scores of 2.0 or higher may indicate need for more frequent D/M surveillance and occupant health awareness. For rooms/areas with observed damage, early identification of water-intrusion sources and timely remediation should be considered. Future epidemiologic studies using DMAT will be valuable for further assessing exposure-response relationships and refining the interpretation of DMAT scores.