Effect of teacher's working conditions on voice disorder in Korea: a nationwide survey.

Background: Korean teacher's working conditions are deteriorating. There is concern about the deterioration of teachers' health and voice disorder is one of the most common problems. Teacher's vocal health is important for them and their students. The aim of the present study was to investigate working conditions that may affect voice disorders.

Methods: In all, 79 primary and secondary schools were randomly selected for a nationwide school system survey ( N  = 3345). In 64 schools, 1617 (48.3%) teachers participated via a postal self-report questionnaire from June 2016 to August 2016. After applying inclusion and exclusion criteria, data from 1301 teachers' were used for analysis. Multiple logistic regression was used to investigate the associations between general, work-related factors, and frequent voice disorders (fVDs) to estimate the adjusted odds ratio(aOR).

Results: Teachers who reported voice symptoms more than once a week (fVD) made up 11.6%. In a multiple logistic regression, fVD was significantly associated with female, difficulty in applying for sick leave as needed, music teachers (primary school), and less than 6 h of sleep per day (primary school). The aOR for fVD was 2.72 (0.83-8.10) in the longest working hours group (> 52 h/wk) among the primary school teachers, and 1.90 (0.80-4.73) in the longest class hour group (≥ 20 h/wk), 1.52 (0.90-2.62) in homeroom teachers among the secondary school teachers, but not statistically significant.

Conclusions: Korean teachers' working conditions are associated with fVDs. The school health system must take steps to prevent and treat voice disorders of teachers.