Dust weight and asthma prevalence in the National Survey of Lead and Allergens in Housing (NSLAH)

Abstract

Background: Settled dust has been used in studies to assess exposures to allergens and other biologically active components, but it has not been considered in the aggregate in relation to respiratory health outcomes in the general population.

Objective: We addressed whether total house dust weight, an index of total dust exposure, was associated with respiratory health outcomes in the National Survey of Lead and Allergens in Housing (1998-1999) (NSLAH).

Methods: NSLAH was a cross-sectional survey designed to represent permanently occupied housing units in the United States. In each household, a questionnaire was administered and settled dust was vacuumed from five locations. Linear regression models were used to identify predictors of dust weight; logistic regression models were used to examine the relationship between dust weight and asthma and wheeze.

Results: Dust weight samples were available for 829 households, and survey information was available for 2,456 participants (children and adults). Lower income, older homes, household pets, having a smoker in the house, and less frequent cleaning predicted higher dust weight levels in U.S. households. Higher levels of dust weight were associated with greater odds of current asthma and wheeze. The strongest associations were seen for wheeze [adjusted odds ratio (OR) = 1.99; 95% confidence interval (CI), 1.21-3.28 for bedroom bed dust; OR = 2.81; 95% CI, 1.52-5.21 for upholstery dust). These associations persisted when adjusting for allergen and endotoxin exposures.

Conclusions: Dust weight, an index of total dust exposure in the home, may contribute to respiratory outcomes independently of the exposure to specific components.

Figure 1

Distribution of dust weight (mg) by location in households, from the NSLAH, 1998–1999. Abbreviations: LR, living room; Max, maximum. Each box extends from the 25th to the 75th percentiles, and the error bars mark the maximum and minimum nonzero value. The dot represents the geometric mean for each location, and the horizontal line represents the median.