Background: We assessed relationships between health symptoms in office workers and risk factors related to moisture and contamination, using data collected from a representative sample of U.S. office buildings in the U.S. EPA BASE study.Methods: Analyses assessed associations between three types of weekly, workrelated symptoms -lower respiratory, mucous membrane, and neurologic -and risk factors for moisture or contamination in these office buildings. Multivariate logistic regression models were used to estimate the strength of associations for these risk factors as odds ratios (ORs) adjusted for personal-level potential confounding variables related to demographics, health, job, and workspace.Results: A number of risk factors were associated (e.g., 95% confidence limits excluded 1.0) significantly with small to moderate increases in one or more symptom outcomes. Significantly elevated ORs for mucous membrane symptoms were associated with the following risk factors: presence of humidification system in good condition versus none (OR = 1.4); air handler inspection annually versus daily (OR = 1.6); current water damage in the building (OR = 1.2); and less than daily vacuuming in study space (OR = 1.2). Significantly elevated ORs for lower respiratory symptoms were associated with: air handler inspection annually versus daily (OR = 2.0); air handler inspection less than daily but at least semi-annually (OR=1.6); less than daily cleaning of offices (1.7); and less than daily vacuuming of the study space (OR = 1.4). Only two statistically significant risk factors for neurologic symptoms were identified: presence of any humidification system versus none (OR = 1.3); and less than daily vacuuming of the study space (OR = 1.3). Dirty cooling coils, dirty or poorly draining drain pans, and standing water near outdoor air intakes, evaluated by inspection, were not identified as risk factors in these analyses, despite predictions based on previous findings elsewhere, except that very dirty cooling coils were associated with a nonsignificant increase in lower respiratory symptoms Conclusions: These preliminary findings suggest that some factors that indicate risks for moisture or contamination in office buildings may have adverse effects on respiratory or neurologic health of office workers. More refined analyses are underway that will include these risk factors in simultaneous multivariate models along with additional risk factors that may be confounders, such as ventilation rate and indoor temperature. Future analyses will also use more refined metrics for both health outcomes and environmental risks, as well as assess risk in susceptible sub-groups.
Background: Metrics of culturable airborne microorganisms for either total organisms or suspected harmful subgroups have generally not been associated with symptoms among building occupants. However, the visible presence of moisture damage or mold in residences and other buildings has consistently been associated with respiratory symptoms and other health effects. This relationship is presumably caused by adverse but uncharacterized exposures to moisturerelated microbiological growth. In order to assess this hypothesis, we studied relationships in U.S. office buildings between the prevalence of respiratory and irritant symptoms, the concentrations of airborne microorganisms that require moist surfaces on which to grow, and the presence of visible water damage.Methods: For these analyses we used data on buildings, indoor environments, and occupants collected from a representative sample of 100 U.S. office buildings in the U.S. Environmental Protection Agency's Building Assessment Survey and Evaluation (EPA BASE) study. We created 19 alternate metrics, using scales ranging from 3-10 units, that summarized the concentrations of airborne moisture-indicating microorganisms (AMIMOs) as indicators of moisture in buildings. Two were constructed to resemble a metric previously reported to be associated with lung function changes in building occupants; the others were based on another metric from the same group of Finnish researchers, concentration cutpoints from other studies, and professional judgment. We assessed three types of associations: between AMIMO metrics and symptoms in office workers, between evidence of water damage and symptoms, and between water damage and AMIMO metrics. We estimated (as odds ratios (ORs) with 95% confidence intervals) the unadjusted and adjusted associations between the 19 metrics and two types of weekly, work-related symptoms -lower respiratory and mucous membrane -using logistic regression models. Analyses used the original AMIMO metrics and were repeated with simplified dichotomized metrics. The multivariate models adjusted for other potential confounding variables associated with respondents, occupied spaces, buildings, or ventilation systems. Models excluded covariates for moisture-related risks hypothesized to increase
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