Abstract
Objectives
Many studies have shown consistent associations between evident indoor dampness or mold and respiratory or allergic health effects, but causal links remain unclear. Findings on measured microbiologic factors have received little review. We conducted an updated, comprehensive review on these topics.
Data sources
We reviewed eligible peer-reviewed epidemiologic studies or quantitative meta-analyses, up to late 2009, on dampness, mold, or other microbiologic agents and respiratory or allergic effects.
Data extraction
We evaluated evidence for causation or association between qualitative/subjective assessments of dampness or mold (considered together) and specific health outcomes. We separately considered evidence for associations between specific quantitative measurements of microbiologic factors and each health outcome.
Data synthesis
Evidence from epidemiologic studies and meta-analyses showed indoor dampness or mold to be associated consistently with increased asthma development and exacerbation, current and ever diagnosis of asthma, dyspnea, wheeze, cough, respiratory infections, bronchitis, allergic rhinitis, eczema, and upper respiratory tract symptoms. Associations were found in allergic and nonallergic individuals. Evidence strongly suggested causation of asthma exacerbation in children. Suggestive evidence was available for only a few specific measured microbiologic factors and was in part equivocal, suggesting both adverse and protective associations with health.
Conclusions
Evident dampness or mold had consistent positive associations with multiple allergic and respiratory effects. Measured microbiologic agents in dust had limited suggestive associations, including both positive and negative associations for some agents. Thus, prevention and remediation of indoor dampness and mold are likely to reduce health risks, but current evidence does not support measuring specific indoor microbiologic factors to guide health-protective actions.
Methods
The online database PubMed (National Library of Medicine 2010) was searched using three groups of keywords such as dampness, damp, “water damage,” moisture, humidity, fungi, fungus, mold, mould, bacteria, or microorganisms, crossed with health, asthma, allergy, eczema, wheeze, cough, respiratory, “respiratory infection,” lung, skin, nasal, nose, “hypersensitivity pneumonitis,” alveolitis, bronchial, hypersensitivity, or inflammation and with building, house, home, residence, dwelling, office, school, or “day-care center.” A similar search was run in the ISI/Web of Knowledge database (Thomson Reuters 2010). We identified additional publications from reference lists and personal databases. Some indoor exposures/conditions were not included, for example, humidity, mattress moisture, and dust mites.
Inclusion of a primary study required the following characteristics:
- Publication in a peer-reviewed journal by November 2009
- Reporting of original data from one of the following study designs: intervention (quasi-experimental intervention), prospective (prospective cohort), retrospective (retrospective cohort or nested case–control), or cross-sectional (cross-sectional or prevalence case–control)
- No minimum study size, but if exposure was characterized only at the building level, inclusion of > 10 buildings
- Including risk factors related to dampness or microbiologic organisms/components/products, other than allergens (dust mites, cockroaches, mice)
- Including allergic or respiratory health effects
- Providing adequate control, in study design or analysis, of selection bias and confounding from key variables: sex, smoking (active in adults, passive in children), and socioeconomic status (SES; control for SES not required if SES shown not to confound in study, if adjusted for race when race highly correlated with SES, if study conducted within specific occupational groups, or if study from Nordic countries or Holland).