Home Dampness Signs in Association with Asthma and Allergic Diseases in 4618 Preschool Children in Urumqi, China-The Influence of Ventilation/Cleaning Habits

There is an increasing prevalence of childhood asthma and allergic diseases in mainland of China. Few studies investigated the indoor dampness, ventilation and cleaning habits and their interrelationship with childhood asthma and allergic diseases. A large-scale cross-sectional study was performed in preschool children in Urumqi, China. Questionnaire was used to collect information on children's health, home dampness and ventilation/cleaning (V/C) habits. Multiple logistic regressions were applied to analyze the associations between childhood asthma/allergic diseases and each sign of home dampness, dampness levels, each V/C habit and total V/C scores. The associations between dampness and health were further performed by strata analyses in two groups with low and high V/C scores. Totally 4618(81.7%) of 5650 children returned the questionnaire. Reports on home dampness were most common for water condensation on windows (20.8%) followed by damp beddings (18.0%). The most common ventilation measure was the use of exhaust fan in bathroom (59.3%), followed by daily home cleaning (48.3%), frequently putting beddings to sunshine (29.9%) and frequently opening windows in winter (8.4%). There were positive associations between the 6 signs of home dampness and children's health particularly the symptoms last 12 months. By comparing with the reference dampness level (dampness scored 0), both the low dampness (scored 1~2) level and the high dampness level (scored 3~6) showed significantly increasing associations with childhood symptoms. There were crude negative associations between V/C habits and childhood health but not significant adjusting for home dampness levels. The risks of home dampness on children's health were lower in the group with higher V/C score but the differences were not statistically significant. Home dampness is a potential risk factor for childhood asthma and allergic symptoms in preschool children in Urumqi, China. No significant effects were observed for ordinary home ventilation and cleaning habits in reducing the risks of home dampness on childhood asthma and allergic diseases in Urumqi, China.