Objective   To investigate whether there was a relationship between the indoor air formaldehyde exposure and allergic asthma in adults.

  Methods   The case-control study method was used to collect the information of the 30 cases and 81 controls.All 111 subjects' indoor air samples were collected and assayed for the concentrations of formaldehyde by standard methods.

  Results   The concentration of the indoor air formaldehyde was higher in cases than that in controls and the difference had statistical significance(P < 0.000 1).After ranking the concentration of formaldehyde into 4 quarters, comparing with the first quarter, the other 3 quarters' unadjustedOR values were increasing respectively and after adjusting for age, gender, present smoking and family chronic bronchitis or asthma history, the OR values were increasing also.Meanwhile, the total trend OR value showed that the risk of the adults' allergic asthma would be increased 2.51 times(unadjusted)and 2.36 times(adjusted)with each quarter increasing of the indoor air formaldehyde concentration.Furthermore, the risk of the adults' allergic asthma would be increased 0.02 times than before when the indoor air formaldehyde concentration increasing each 1μg/m³.Simultaneously, the study also indicated that decoration could increase the indoor air formaldehyde concentration 30.65μg/m³ averagely.

  Conclusion   There was a definite dose-response relationshtp between the adults' allergic asthma and indoor air formaldehyde exposure.But the obvious risk would be showed up only when the concentration of the indoor air formaldehyde reached to a certain high level.