Asthma, mite sensitization, and sleeping in bunks

Background: Mattresses and bedding are the main reservoirs of house dust mi tes. Objective: Subjects sleeping in the bottom bunk may be exposed to house dus t particles detached from bedding of the top bunk. Our aim was to ascertain whether this exposure could influence the development of mite sensitizatio n and/or allergic symptoms in these individuals. Methods: Symptoms of allergic respiratory disease were recorded and mite sk in tests performed in 94 consecutive bunk-sleeping subjects (47 pairs of si blings) from an outpatient allergy clinic. Levels of Der p I, Der f I, and Der II were determined by enzyme-immunoassay in 16 randomly selected beddin g dust samples (8 pairs of bunks). Results: Mite sensitization rate and prevalence of allergic respiratory dis ease were similar for the top-bed and bottom-bed groups, whereas prevalence of asthma was significantly higher in the latter. Mite sensitization was s ignificantly associated with family atopy background, whereas other factors such as house pets, indoor smoke exposure or types of mattress or bunks we re not. Der p I levels higher than 2 mu g/g dust were found in 12 of the 16 mattresses and the median of the 8-bed-bottom group was over 10 mu g/g. Conclusions: Sleeping in bunks constitutes a greater risk of developing ast hma for subjects sleeping in the bottom bed. Bunk sleeping should be discou raged in families with an atopic background and sensitized subjects should use the top bed.