LAUSR

BACKGROUND Endotoxin exposure may cause asthma exacerbations and contribute to non-atopic respiratory diseases. Viet Nam, a country with multiple house types, is lacking data on indoor contamination by endotoxin in regard with house types. OBJECTIVE The comparison of measured settled dust endotoxin levels among house types in Ho Chi Minh city will allow to classify the house types regarding health risks. METHODS This study is a cross-sectional study. Five identified house types were selected: apartment (APA), rental (REN), rural (RUR), slum (SLU) and tube house (TUB). One hundred house's endotoxin contamination was evaluated by questionnaire and dust sampling. Endotoxin concentration was measured by kinetic chromogenic Limulus assay. RESULTS dotoxin concentration (geometric mean 126.0 EU/mg, 95%CI 118.3-133.7) is particularly high in settled house dust compared to western countries and is significantly associated with the house type. The highest level was found in RUR in each room (p = 0.002 for living room; p < 0.0001 for bedrooms and for kitchens). Concerning levels in the different rooms, APA and TUB form a low group while REN and SLU (p < 0.001) form a median group and RUR the highest (p < 0.001). Differences in endotoxin levels were associated to the presence of dog, chicken and farm animals, wood cooking, air-conditioning usage. CONCLUSIONS Further understanding of the relevant factors to endotoxin levels would contribute to prevent asthma exacerbations and chronic respiratory diseases. Public health interventions to reduce exposure to endotoxin include improving housing conditions, eliminating risk factors and a priority to high-risk house types.