Vocal effort and voice handicap among teachers.

The relationship between voice handicap and professional vocal effort was investigated among teachers in a cross-sectional study of census nature on 4496 teachers within the public elementary education network in Salvador, Bahia, Brazil. Voice handicap (the outcome of interest) was evaluated using the Voice Handicap Index 10. The main exposure, the lifetime vocal effort index, was obtained as the product of the number of years working as a teacher multiplied by the mean weekly working hours. The prevalence of voice handicap was 28.8% among teachers with high professional vocal effort and 21.3% among those with acceptable vocal effort, thus yielding a crude prevalence ratio (PR) of 1.36 (95% confidence interval [CI]=1.14-1.61). In the final logistic model, the prevalence of voice handicap was statistically associated with the professional vocal effort index (PR=1.47; 95% CI=1.19-1.82), adjusted according to sex, microphone availability in the classroom, excessive noise, pressure from the school management, heartburn, and rhinitis.