The increased prevalence of asthma over the last 30 years has been reported from many different countries, including Korea. The increased prevalence may be due to increased exposure to indoor air pollutants.

In this study, the relationship between residential environments and airway hyper-responsiveness has been examined among 280 family members. The bronchial hyper-responsiveness was expressed as the log-transformed slope of FEV decrease over the log-transformed dose of methacholine concentration(BRindex). Simple regression analysis was done for the effect of sex, age, atopic status, and residential environments including active and passive smoking exposures on airway responsiveness. Based on simple regression results, multiple rwegression analysis was performed for total group and also according to sex.

The mean of BRindex of residents living in gas boiler heating houses was higher than that of central heating system (p=0.014). Smoking status was a significant determinant of bronchial hyper-responsiveness in both genders; male(p=0.017), female (p%.022). In the male group the mean of BRindex of current smokers was significantly higher than those of ex-smokers and non-smokers, and the mean of BRindex of passive smokers was higher than that of non-smokers, but statistical significance was border-line(p=0.069). In female group, the mean of BRindex of kerosene stove users was higher than that of non-users(p=0.057).

This study suggests that indoor air pollutants including type of heating, passive smoking and kerosene stove use can contribute to the increase in asthma prevalence in Korea.