Nationwide study of sick house syndrome: comparison of indoor environment of newly built dwellings between Sapporo city and Southern areas including those in Honshu and Kyushu.

The aims of this study are to evaluate the associations between residential factors and sick house syndrome (SHS) in a cold region and in a temperate region in Japan.A questionnaire survey was conducted on dwellings aged within 7 years from 2003 to 2004 in Sapporo and 'Honshu and northern Kyushu' including Fukushima, Aichi, Osaka, Okayama, and Kitakyushu. The questionnaire consisted of questions about the characteristics of dwellings, manner of living, and health problems of occupants. SHS was identified from the 'yes' responses to the questions on the five items on nasal, throat and respiratory, eyes, skin, and general symptoms that appeared frequently or sometimes at home and improved upon leaving the home.The dwellings with the SHS problem, where at least one inhabitant reported any symptoms of SHS, were 4.7% in Sapporo City and 3.3% in Honshu and northern Kyushu. Regarding ventilation, the principal method was the enforced ventilation in Sapporo and ventilation from open windows in Honshu and northern Kyushu. The sums of five signs of dampness were 0.8 +/- 1.0 in Sapporo and 1.3 +/- 1.0 in Honshu and northern Kyushu. The elevated scores were accompanied by the increased percentage of SHS in both groups. Condensation on both window panes and walls was strongly associated with SHS.Differences were found in the ventilation method and in the dampness state between Sapporo and Honshu and northern Kyushu. In both groups, the dampness state was associated with SHS.