© 2004 American Thoracic Society
Fungi and Respiratory Illness in ChildrenTo the Editor:Literature indicates that home dampness is associated with respiratory tract illness in children (1–3). The recent study by Stark and colleagues (4) suggests that this association may be mediated by the presence of fungi in the home environment. This is an important result not only because of potential identification of a mechanism of disease, but it also suggests possible interventions. However, there are a number of methodologic details of the study that need clarification so that other investigators may attempt to replicate these findings and also for the application of these results in clinical practice. First, how were the concepts of "water damage in home" and "mold/mildew inside home" defined and operationalized (see Table 3 of Stark and colleagues [4])? How much water damage and mold/mildew was required for a positive result? Were these items based on questions asked of parents? If so, what questions were asked? Or, were these covariates defined on the basis of observations or measurements made during the home visit by the research technicians? In this latter case, what were the criteria used by the technicians to define these concepts? Airborne and vacuum samples for fungal analyses were obtained on one occasion from each home. It was stated that these samples were obtained during the first home visit when the index child was 2 to 3 months old. Because the season of birth varied, this would mean that the season of fungal sampling also varied, and fungal samples were correlated with season of birth, although they lagged by 2 to 3 months. Most importantly, fungal samples were not obtained under the same conditions in all homes, specifically during the same season. It is well known that airborne, and to some extent surface, fungal levels vary by season, as does the incidence of respiratory illnesses. Therefore, the apparent association of airborne fungi with lower respiratory illness may be an artifact due to confounding of fungal sampling with season of measurement. Was this issue addressed in analyses, and if so, how?
University of Michigan School of Public Health Ann Arbor, Michigan FOOTNOTES Conflict of Interest Statement: A.F. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
From the Authors: We thank Dr. Franzblau for his comments on our article (1). Although there is extensive literature demonstrating associations of "home dampness" with childhood respiratory illness and symptoms, there is no consensus on the definition of dampness, nor on the metric for measuring it (2). In a study of 4,625 children from six U.S. cities, Brunekreef (3) reported an association of home dampness with respiratory symptoms. Since this report was published, many investigators have applied the Six City Study questions used to investigate home dampness and have found similar associations (4). A recent report by the Institute of Medicine concludes that with their acknowledged limitations, questions regarding home dampness are a well established and accepted epidemiologic tool to investigate associations between dampness and respiratory disease (2). The questions that we applied to our study (1) were: During the past 12 months, has there been water damage to the building or its contents, for example, from broken pipes, leaks, or floods?; and During the past 12 months, has there been any mold or mildew on walls or other surfaces (other than food) inside the home? The technician was trained to administer the questionnaire without bias. The definition of home dampness did not involve a home inspection, which may be useful in defining moisture problems, but can also miss previous episodes of flooding that can initiate dampness-associated problems without visible evidence for mold or other problems resulting from dampness and without detectable moisture in a point measure (5). As demonstrated in our analyses, when we investigated the relation of fungal levels and of dampness to respiratory illness, we adjusted for season of birth, which was indeed associated both with fungal level and with lower respiratory illness. However, high fungal levels in the home remained a strong independent predictor of lower respiratory illness in multivariate models including season.
a Brigham and Women's Hospital, Harvard Medical School Boston, Massachusetts FOOTNOTES Conflict of Interest Statement: D.R.G. and P.C.S. do not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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