The effect of dampness on sick building syndrome (SBS) symptoms has not been fully investigated in Japan. The purpose of this study is to elucidate the possible effects of dampness on SBS symptoms among residents in Japanese public apartment houses.

A questionnaire was used to investigate the degree of dampness in public apartment houses in Asahikawa, Japan, and its effect on SBS symptoms, involving 480 residents in 64 buildings. Dampness indicators were as follows: condensation on the windowpanes, condensation on the walls and/or closets, visible mold in the bathrooms, visible mold on the walls, window frames, and/or closet, moldy odor, slow drying of the wet towels in bathrooms, water leakage, and bad drainage in bathrooms.

All dampness indicators except for visible mold in bathrooms had significantly higher odds ratios ( ORs ) for all or any SBS symptoms after adjustment. The dampness index, the number of positive dampness indicators, was significantly related to all SBS symptoms after adjustment.

There are serious problems relating to dampness in Japanese public housing, which affects the health of residents. There is a need to educate the residents about the relationship between dampness and SBS, and building problems should be rectified.