Self-reported voice disorders of teachers and indoor air quality in schools: a cross-sectional study in Finland

Objective: We aimed to study the association between self-reported voice disorders among teachers and indoor air quality in school buildings.
Methods: We performed a questionnaire study of 538 Finnish teachers working in 67 school buildings utilizing both perceived and technical evaluations; the agreement between these two assessments was also studied. The technical assessment was provided by technical experts.
Results: Teachers with voice disorders reported significantly more complaints from indoor air than those without voice disorders. The results also indicated a possible connection between the technical assessment and voice disorders. After adjustment for sex, stress and asthma, the prevalence of voice disorders was 47% higher in teachers working in renovated buildings compared to those working in the non-problem buildings (aRR1.47; CI 95% 1.11–1.95). The prevalence of voice disorders was 28% higher among teachers working in buildings with problems compared to those working in non-prob- lem buildings (aRR 1.28; 95% CI 0.99–1.64).
Discussion: In our study, poor perceived indoor air was significantly associated with self-reported voice disorders in teachers and there was an agreement between the perceived and technical assess- ments. Our results also indicated a possible connection between the technical assessment and voice disorders. Our results imply the need for longitudinal research with technical assessment to study the effect of renovation on voice disorders.