Increased risk of allergy in children due to formaldehyde exposure in homes

Background: Formaldehyde levels were measured in 80 houses in the Latrobe Valley, Victoria, Australia. An association between exposure to formaldehyde and sensitization to common aeroallergens has been suggested from animal trials, but no epidemiologic studies have tested this hypothesis. Methods: A total of 148 children 7-14 years of age were included in the study, 53 of whom were asthmatic. Formaldehyde measurements were performed on four occasions between March 1994 and February 1995 with passive samplers. A respiratory questionnaire was completed, and skin prick tests were performed. Results: The median indoor formaldehyde level was 15.8 mu g/m(3) (12.6 ppb), with a maximum of 139 mu g/m(3) (111 ppb). There was an association between formaldehyde exposure and atopy, and the adjusted odds ratio was 1.40 (0.98-2.00, 95% Cl) with an increase in bedroom formaldehyde levels of 10 mu g/m(3). Furthermore, more severe allergic sensitization was demonstrated with increasing formaldehyde exposure. On the other hand, there was no significant increase in the adjusted risk of asthma or respiratory symptoms with formaldehyde exposure. However, among children suffering from respiratory symptoms, more frequent symptoms were noted in those exposed to higher formaldehyde levels. Conclusions: Low-level exposure to indoor formaldehyde may increase the risk of allergic sensitization to common aeroallergens in children.