2020 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7246888/ Tao, Yaping Asia Observational Exposure Study Teachers Elementary (K-5) Vocal load Network questionnaire Voice handicap index Daily class hours Types of voice usage Our results indicated, based on the Voice Handicap Index scale (VHI-10, China), that the prevalence of voice disorders in early childhood teachers was 59.7%, while that in elementary school teachers (65.5%) was significantly higher than that in kindergarten teachers (54.0%) during the previous semester. Contributing factors included daily class hours, classroom air humidity, and speaking loudly during teaching. Additionally, certain types of voice usage in teaching such as falsetto speak, speaking more than other teachers, not using vocal techniques, and habitual voice clearing, were significantly associated with voice disorders. Conclusion: Most early childhood teachers have voice disorders. Compared with the kindergarten teachers, the elementary school teachers experienced a significantly higher prevalence of voice disorders. Several factors among work organization, work environment, and types of voice usage in teaching were associated with the voice disorders in early childhood teachers. The finding suggests that voice training should be provided for early childhood teachers, classroom teaching time should be decreased, and the number of teachers in basic subjects should be increased in the lower grades of elementary schools.