[Symptoms of sick house syndrome and contributory factors; study of general dwellings in Hokkaido].

Objective: The aim of this study was to clarify the "Sick House Syndrome" which has recently received increasing attention, and to investigate relationships between symptoms and the state of general dwellings in Hokkaido.

Methods: Questionnaires were sent to residents in 1775 dwellings, mainly solitary houses built or remodeled within the past few years by 24 construction companies in Sapporo and its environs, and answers was received from 564. The questionnaires included queries about building structure and characteristics, the residents' habits in the home, and subjective symptoms. We requested one resident who had the most severe symptoms in the dwelling to answer a questionnaire about symptoms. We classified the symptoms into 11 categories, and selected those that developed or were aggravated after the building or remodeling. We defined dwellings in which inhabitants complained of one or more categories of symptoms as the group with sick-house-related disease (developed or aggravated group: DA group), and those in which the inhabitants complained of two or more symptoms as the group with sick house syndrome (more than one organic symptom group: MO group)". Associations between symptoms and dwellings were then studied.

Results: There were 201 dwellings for which residents complained of symptoms (37.2%). Of these, 94 were in the DA group (16.7%), and 57 (10.1%) in the MO group. The symptoms that developed or were aggravated after building or remodeling of the dwellings were throat, 7.1%, dermal, 6.9%, psychoneural, 5.3%, eye, 5.1%, and nasal problems, 4.1%. Unpleasant odors form furniture were significant in both groups (DA: crude odds ratio (OR) 2.66, MO: OR 3.24). Use of aromatics was significant in group DA (OR 1.78). Condensation on windows and mold growth in the dwellings were significant in both groups (condensation on windows; DA: OR 2.98, MO: OR 3.32, mold growth; DA: OR 3.11, MO: OR 3.24). In addition, the percentage of dwellings for which residents complained of symptoms increased with signs of dampness (condensation on windows and mold growth). On logistic regression analysis, condensation on windows and mold growth were significant in both groups, and unpleasant odors from furniture in the MO group.

Conclusion: It is suggested that symptoms of sick house syndrome are associated with high humidity such as condensation on windows and mold growth, odors from furniture and use of aromatics.