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OBJECTIVE: To examine the hearing status of pre-job workers exposed to noise in metal manufacturing industries,and to analyze the related influencing factors. METHODS: A judgement sampling method was adopted to choose1 597 pre-job workers exposed to noise in metal manufacturing industries as the study subjects. The data of workers' occupational health examination was collected,and the influencing factors of hearing loss were analyzed. RESULTS: Among the 1 597 individuals,631( 39. 5%) cases reported occupational noise exposure history( noise exposure group) with the length of service of 0. 20( 0. 10-0. 30) years; 966( 60. 5%) cases denied occupational noise exposure history( no-noise exposure group). The hearing loss detection rate was 46. 1%( 737 /1 597); among them,the occupational contraindication detection rate was 13. 9%( 222 /1 597),and the detection rate of other kinds of hearing loss was 32. 2%( 515 /1 597).The detection rates in workers with occupational contraindication and the other kinds of hearing loss in noise exposure group were higher than those in the non-noise exposure group( 16. 5% vs 12. 2%,50. 6% vs 43. 3%,P < 0. 05). The male workers had higher incidence than female workers [the odds ratio( OR) were 1. 958 and 2. 331,respectively,P < 0. 01);the workers with age > 25 years had higher incidence than those with age ≤ 25 years( OR were 2. 390 and 2. 245,respectively,P < 0. 01); the noise exposure workers had higher incidence than non-noise exposure ones( OR were 1. 536 and 1. 287,respectively,P < 0. 05). CONCLUSION: Pre-job occupational health examination is helpful for early detection of occupational contraindication in noise exposure workers. Attention should be paid to the male workers,the older workers,and those with occupational noise exposure history when conducting occupational health examination.
RESUMEN
<p><b>OBJECTIVE</b>To investigate the frequency of numerical aberrations for chromosomes 7 and 8 in the sperms of workers exposed to benzene series.</p><p><b>METHODS</b>Numerical aberrations in the sperms of workers were detected by two-color fluorescence in situ hybridization with biotin labeled chromosome 7 probe (D7Z1) and digoxingenin labeled chromosome 8 probe (D8Z1).</p><p><b>RESULTS</b>The time-weight average air concentration (TWA) of benzene in the workshop was 42.29 mg/m(3), which was significantly higher than that of the national maximum allowable concentration [6 mg/m(3)]. The concentration of urinary trans,trans-muconic acid(ttMA) in the exposed group was also higher than that of the control group. In all, 155721 sperm nuclei from 15 workers in the exposed group and 123771 sperm nuclei from 12 individuals in the control group were examined. The results showed that the frequency of diploidy sperms and the frequencies of disomic sperm for chromosomes 7 and 8 in the exposed group (0.129%, 0.170%, 0.078%) were significantly higher than those of the control group (0.055%, 0.053%, 0.033%), respectively. The frequencies of nullisomic sperm for chromosomes 7 and 8 in the exposed group (0.165%, 0.088%) were also significantly increased, compared with those of the control group (0.056%, 0.029%). A statistically significant difference in the frequency of overall numerical chromosome aberrations was seen between the exposed group (0.745%) and the control group (0.289%).</p><p><b>CONCLUSION</b>The results suggested that higher concentration of benzene may induce higher frequencies of numerical aberrations in the sperms of workers exposed to benzene series.</p>