Objective: To determine the relationship between mite allergen (Der p I) concentrations in house dust and presence of chronic respiratory symptoms in children.
Design: Case control study.
Setting: The provinces of Gelderland and North-Holland in the Netherlands.
Method: Questionnaires were handed to pupils of 38 schools to take home; about 6000 were returned (80% response). A home visit was paid to 259 children with chronic respiratory symptoms ('cases') and to 257 symptom-free 'control' children. Using an enzyme immunoassay the Der p I concentrations of living room floor dust, bedroom floor dust and mattress dust were determined. Specific IgE was determined in serum.
Results: Der p I concentrations higher than 2000 ng/g were found in 86% of the dwellings and concentrations higher than 10,000 ng/g in 55%. Cases were exposed to lower Der p I concentrations than controls. However, cases sensitised to dust mites were exposed to higher Der p I concentrations than non-sensitised cases, both living in homes where no allergen avoidance measures had been taken in the past.
Conclusion: Exposure to Der p I in the home was associated with sensitisation to dust mites in children with chronic respiratory symptoms living in homes where no allergen avoidance measures had been taken.