Asthma symptoms in relation to building dampness and odour in older multifamily houses in Stockholm.

SETTING: Respiratory symptoms and hay fever in adults in relation to the indoor environment.
OBJECTIVES: To study relationships between reports on respiratory symptoms and hay fever and building dampness and odours in older multifamily dwellings.
DESIGN: A questionnaire study in a random sample of 231 multifamily buildings built before 1961, which included 4224 apartments. The response rate was 77% (n = 3241). Information on building characteristics was gathered from building owners and the central building register in Stockholm. Multiple logistic regression analysis was applied, adjusting for age, sex, current smoking, population density, type of ventilation and ownership.
RESULTS: In total, 22% reported at least one sign of dampness, and 32% reported odour in the dwelling. All types of odours were more common in damp buildings. Reports on dampness and odours were related to asthma symptoms and current cough, even when adjusting for potential confounders. A combination of odour and signs of high air humidity was related to an increase in asthma symptoms (OR = 2.82; 95%CI 2.70-2.95) and current cough (OR = 5.29; 95%CI 4.99-5.62). Similar findings were observed for a combination of odour and history of water leakage in the last 5 years, with an increase in asthma symptoms (OR = 3.59; 95%CI 3.37-3.82) and current cough (OR = 2.86; 95%CI 2.61-3.14). There was a dose-response relationship between respiratory symptoms and the number of signs of dampness. An association was also observed between dampness and a history of pollen allergy.
CONCLUSIONS: Signs of high indoor air humidity, water leakage and odours were common, and related to respiratory symptoms. Exposure to odorous compounds from building dampness may be significant with respect to respiratory symptoms and possibly atopic sensitisation.