Wood stove heating, asthma and allergies

In two German studies household wood or coal stove use was negatively assoc iated with atopic sensitization and allergic rhinitis in childhood. Wood st ove heating is strongly related to 'traditional lifestyle' and therefore su bjected to confounding factors possibly yet not known. The study was conduc ted to study these factors and the independent impact of early exposure to wood stove heating on subsequent asthma and atopic disease. In a questionna ire survey among 10667 Finnish university students aged 18-25 years, we inv estigated the association between wood stove heating at age 0-6 years and a sthma and allergies up to young adulthood. Adjustment was made for factors related to the heating system and atopic disorders by using multivariate re gression. Unadjusted lifetime prevalence rates for physician-diagnosed asth ma, allergic rhinoconjunctivitis, atopic dermatitis and self-reported wheez ing were lower among subjects with wood stove heating compared to other hea ting systems. There was a significant negative association between childhoo d wood stove heating and allergic rhinitis or conjunctivitis in the univari ate model (OR 0.61, 95% CI 0.61-0.91), but not for the other diseases. The significant association disappeared in the multivariate analysis after adju sting for various family indoor and outdoor (adjusted OR 0.96, 95% CI 0.77- 1.20) factors. The association between wood stove heating and allergic rhin oconjunctivitis was mainly confounded by childhood residential environment, especially the farm environment, Farm environment was found to be the main confounding factor related to association between wood stove heating and a sthma, and atopic diseases. (C) 2001 Harcourt Publishers Ltd.