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Comparison of Work-related Symptoms and Visual Contrast Sensitivity between Employees at a Severely Water-damaged School and a School without Significant Water Damage
Citation:
Thomas, G., N. C. Burton, C. Mueller, E. Page, AND S. J. VESPER. Comparison of Work-related Symptoms and Visual Contrast Sensitivity between Employees at a Severely Water-damaged School and a School without Significant Water Damage. AMERICAN JOURNAL OF INDUSTRIAL MEDICINE. John Wiley & Sons, Ltd., Indianapolis, IN, 55(9):844-854, (2012).
Impact/Purpose:
Approximately 9% of children have asthma. The medical costs of asthma are approximately $15 billion per year in the US alone and asthma results in about 2,000 deaths per year (Fisk et al. 2007). Lost school and work days run into the millions each year. The IOM’s expert committee (2004) concluded that exposure to moldy, damp indoor environments was associated with asthma. A subsequent review (Sahakian et al. 2008) of more recent publications also linked dampness to mold and asthma/asthma symptoms. The World Health organization has come to the same conclusion and suggest that exposure to molds should be “minimized” (WHO 2009). A meta-analysis of studies associating mold contamination with adverse health effects demonstrated that building dampness and mold were associated with approximately a 30 to 50% increase in a variety of respiratory and asthma-related health outcomes (Fisk et al. 2007). Therefore, it is critical that mold assessments are accurate and meaningful. US EPA researchers developed a DNA-based method of mold analysis called MSQPCR which is sensitive, specific and accurate. The US EPA in conjunction with HUD developed a simple, standard method of sampling homes for mold populations and created a scale called the ERMI to compare the mould burden in homes across the US (Vesper et al. 2007). In four epidemiological studies, higher ERMI values in homes were associated with increased risk of asthma in children. Remediating the water-damage and mould in asthmatics homes resulted in a statistically significant improvement in the child’s health and a reduction in the need for hospitalizations and emergency room visits (Kercsmar et al. 2006). Although these results are from a limited number of studies and have not been corroborated independently by other research groups, they are suggestive of the conclusions that mold problems are not always obvious. Furthermore, discovering hidden mold is possible using the ERMI analysis and subsequently correcting a mold problem may reduce asthma’s costs to the US by reducing hospitalizations and emergency room visits.
Description:
NIOSH received a request for a health hazard evaluation at a water-damaged school in New Orleans, Louisiana. Employees submitted the request because of concerns about exposure to mold in their school building. We administered a work history and health symptom questionnaire. We also conducted visual contrast sensitivity testing using the F.A.C.T.® handheld chart and collected environmental samples for culturable and aerosolized fungal spores. We collected vacuum dust samples for analysis by a DNA-based technology, called the environmental relative moldiness index (ERMI). We performed a similar evaluation at a comparison school in Cincinnati, Ohio, that had no history of ongoing water intrusion or mold growth. Of 119 employees at the water-damaged school, 95 (80%) participated in the evaluation. Of 165 employees at the comparison school, 110 (67%) participated. Employees at the water-damaged school had higher prevalences of work-related rashes and nasal, lower respiratory, and constitutional symptoms than those at the school without significant water damage. VCS values across all spatial frequencies were lower among employees at the water-damaged school. Actively growing Cladosporium was found on the walls of the water-damaged school. The ERMI values ranged from 13.8-19.1, confirming the presence of mold. Cladosporium and Pencillium were the most prevalent genera both inside and outside the school. Aspergillus species were detected in inside samples but not in outside air samples. No fungal growth was detected on six of eight sticky tape samples collected at the comparison school. Air samples for mold showed low counts on inside samples compared to outside samples. Although mold contamination was the most obvious exposure in the water-damaged school, Further studies are needed to determine what factors are responsible for the health effects observed.
