Occupational therapy adaptation of the home environment in Sweden for people with asthma

The purpose of this study was to evaluate changes of lung function, respiratory symptoms and indoor air quality after reducing allergens and indoor pollutants in the home environment of people with asthma (n = 21). A quasi-experimental pre-/post-test design with one group of participants was implemented. The interventions included removal of wall-to-wall carpets (n = 14) or improvement of indoor air exchange (n = 7). Participants' lung function, symptoms, medication and type-1 allergy were recorded before and after the intervention. The indoor environment was monitored at house calls by an occupational therapist using conventional physical, biological and chemical methods. There was an improvement of lung function evidenced by an increased mean Forced Expiratory Volume (FEV(1) %) and a reduction of airway obstruction (reversibility, % of baseline value), which indicate an improved asthmatic condition. Lung function assessed by vital capacity, bronchial hyper-responsiveness, mean of Peak Expiratory Flow, symptom score and medicine consumption did not change significantly. There was a tendency that the amount of airborne dust (p=0.06) was reduced in the indoor environment. Relative humidity, carbon dioxide, formaldehyde and house dust mite levels had decreased after the intervention, but not significantly. Asthma symptoms related to the home environment are probably caused by several factors. When people with asthma suffer from increased symptoms in the home, house calls should be performed routinely. Dust samples from beds and carpets for analysis of allergens give information about exposure, and environmental assessments should be performed before interventions. Occupational therapists can make a valuable contribution in evaluating the home environment and suggesting ergonomic adaptations for individuals with asthma.