| Notoriously "sick" buildings generate adverse publicity which may distort studies of the relationship between sick building syndrome (SBS) and indoor air quality. We surveyed 1135 workers from 42 smoke-free offices without the "sick" label to assess SBS in its wild state, to estimate its background prevalence, and to identify factors that influence the estimate.;Questionnaires were randomly administered during routine physical examinations each workday for 4 months. One type of questionnaire mentioned that an SBS study was being conducted before assessing SBS-related symptoms, the second type assessed these symptoms without mentioning the SBS study and was used for comparison. The symptom recall period was randomized on the questionnaires for 24-hour, or seven day periods. Symptom severity at work was assessed as a measure of workplace temporality, and allergy/cold/flu were assessed as confounders. SBS was defined as at least one symptom that was temporarily related to work after controlling for confounders; it was assessed by questionnaire type, recall period, workday, building ventilation system, symptom constellation, age/gender, and study time-period.;SBS prevalence was 5.0% (95%CI:3.7,6.3) according to the study's case definition, and this estimate places SBS ahead of cumulative trauma disorder as the most common occupational-related illness. SBS prevalence (P) was significantly (p ;The SBS prevalence estimate was thus found to be influenced by the following factors: questionnaire type, recall period, and gender of worker. Future investigators should consider these factors when comparing results among SBS studies in addition to apparent differences in indoor air quality. Because SBS prevalence was not higher toward the end of the work week compared to the beginning, it may not follow a dose-response relationship, or symptoms may resolve between workdays. There is no symptom constellation specific for SBS, so investigators must assess workplace temporality and confounders to accurately classify SBS status in studies of causes and cures for SBS in the office workplace. |
