BEYOND AIR-QUALITY - FACTORS THAT AFFECT PREVALENCE ESTIMATES OF SICKBUILDING SYNDROME

If the prevalence of sick building syndrome (SBS) is estimated before intervention begins, then a reduction in the estimate may later be use d to measure success of the intervention, and in particular, those eff orts toward improving air quality. However, the measure of success wil l be distorted if factors other than air quality affect the SBS preval ence estimate. in this study the background prevalence of SBS was esti mated and study factors identified that alone affected the estimate. T wo symptom questionnaires were randomly administered to workers from 3 9 offices before routine physical examinations; one questionnaire desc ribed the SBS study, the other did not. SBS was defined as a symptom i n the prior 24-hour or 7-day recall period that was more severe at wor k and not related to suspected confounders-allergy, cold, flu. Prevale nce and prevalence ratios were estimated along with 95% confidence int ervals (CI). Symptoms were reported by 45% of 1088 workers surveyed, b ut most reported them as more severe outside work or related them to c onfounders. SBS prevalence was 5%. it was 3.2 times higher (95% CI: 1. 8, 5.7) among workers cognizant of the study relative to those blinded , 2.2 limes higher (95% CI: 1.2, 4.1) for the 7-day relative to the 24 -hour recall period, and 2.5 times higher (95% CI: 1.4, 5.0) for femal es. SBS prevalence did not differ by workday or age. Since study facto rs alone affected prevalence estimates, a standardized assessment meth od seems necessary for SBS.