Based on the OSHA Standard, there were 58 hearing loss cases in all investigated workers,
resulting in a prevalence rate of 23.5%. All these hearing loss cases were sensorineural hearing
loss cases. The number of hearing loss cases in group 1, group 2 and group 3 were 10 (prevalence
rate: 15.9%), 12 (14.3%), and 36 (36.0%) respectively. The number and prevalence of
hearing loss by selected characteristics in different groups of the subjects was showed in
Table 5. Significant trends of increased prevalence of hearing loss from group 1 to group 3
were observed by all characteristics (P < 0.05) except for worker with experience of smoking
and other landfill-related work.
The multivariate unconditional Logistic regressions gave estimated odds ratios and the corresponding
95% CIs for groups and potential confounders, including different groups, gender,
age, years of education, drinking, smoking status, duration of work and other landfill-related
work (Table 6). Hearing loss was found to be significantly higher in group 3 in the models