Background
Occupational hearing loss associated with noise is becoming more and more serious, and occupational noise-induced deafness has become the second most frequently reported occupational disease in China.
Objective
To characterize occupational hearing loss in Zhejiang Province so as to provide a basis for the formulation of hearing protection strategies and measures.
Methods
Through the occupational diseases reporting system, the data of new cases of occupational noise-induced deafness in Zhejiang Province from 2006 to 2020 and the audiometry results of laborers who were exposed to occupational noise and participated in physical examinations from 2015 to 2020 were collected. The distribution of new cases of occupational noise-induced deafness were described in categories of region, year, industry, enterprise scale, age, onset age, and length of work, as well as the detection of increased high-frequency hearing threshold of workers who ordered occupational health examination in each year.
Results
A total of 575 cases of occupational noise-induced deafness were reported in Zhejiang Province from 2006 to 2020, of which 526 cases were male and 49 were female. The mean onset age of patients with noise-induced deafness was (44.8±8.0) years. There was a significant difference in mean onset age between male and female (t=3.420, Ρ=0.001). The median length of work M (P25, P75) at the time of onset was 9.0 (5.5, 13.2) years. The number of cases of noise-induced deafness and its proportion to the total number of occupational diseases in a year showed an increasing trend from 2006 to 2020 and the average annual growth rate was 22.11%. The patients were mainly distributed in the Hangzhou, Ningbo, and Jiaxing, and the number of cases were 194, 140, and 112, respectively, accounting for 77.5% of the total cases in Zhejiang Province. Manufacturing industry was dominant one in terms of the number of cases, which accounted for 89.6% (515 cases). Private economic enterprise, in terms of economic type, accounted for 57.4% (330 cases). There were significant differences in the length of work at the time of onset among different economic types of enterprises (H=29.081, Ρ<0.001). There were 215 cases in the medium-sized enterprises and 265 in the small- and micro-sized enterprises, respectively, accounting for 83.5% of the the total number of cases.
Conclusions
From 2006 to 2020, the cases of occupational noise-induced deafness in Zhejiang Province present an increasing trend, with a relatively short length of work at the time of onset, and regional and industrial agglomeration.