"This study describes the effects of teaching activities on voice problems in male and female teachers. Over 38% of the teachers studied complained that teaching had an adverse impact on their voice and 39% of those had cut back their teaching activities as a result.
A study by Dr.Elaine Smith in 1998 of the Department of Preventive Medicine, University of Iowa, USA and others.
"This study describes the effects of teaching activities on voice problems in male and female teachers. Over 38% of the teachers studied complained that teaching had an adverse impact on their voice and 39% of those had cut back their teaching activities as a result. Compared to males, female teachers more frequently reported a voice problem (38%v 26%). For every type of course taught, women had a higher probability of reporting voice problems compared to men.
This was the first study to show that in the same occupation, females report a higher frequency of vocal symptoms than males even when teaching characteristics and years of employment are similar."