RESUMEN
Background Non-Gaussian noise has become the dominant noise type in industry. However, the epidemiological characteristics of non-Gaussian noise exposure and associated noise-induced hearing loss (NIHL) are still unclear. Objective To summarize the epidemiological characteristics of NIHL associated with non-Gaussian noise in manufacturing industry in China and provide a basis for the early prevention and control of occupational hearing loss. Methods Chinese and English literature on hearing loss associated with non-Gaussian noise in China were retrieved. The overall prevalence was calculated based on the prevalence data provided by each included study. A meta-analysis of studies with Gaussian noise as a control group was also performed and the overall weighted odds ratio (OR) was calculated to compare the effects of non-Gaussian noise and Gaussian noise on hearing loss. Publication bias was evaluated by funnel plot and Egger regression, and a sensitivity analysis was performed by eliminating references in turn. Results A total of 37 cross-sectional studies involving 25 055 Chinese manufacturing workers exposed to non-Gaussian noise were included, 92.5% of whom were male. These workers aged (32.7±9.6) years were exposed to non-Gaussian noise at (87.0±4.2) dB(A) for (6.8±4.9) years. The mean cumulative noise exposure (CNE) was (95.9±8.0) dB(A)·year. The prevalence rate of high-frequency NIHL (HFNIHL) and speech-frequency NIHL (SFNIHL) were 29.0% and 14.2%, respectively. The results of the meta-analysis treating 19 cross-sectional studies with Gaussian noise as a control group showed that there were no significant differences in age, exposure duration, and equivalent continuous A-weighted sound pressure level (LAeq), and CNE between the non-Gaussian noise group and the Gaussian noise group. The overall weighted OR of HFNIHL was 1.87 (95%CI: 1.46−2.41), which was statistically significant. The funnel plot showed good symmetry and the result of Egger regression was t=−0.11, P=0.910 (>0.05), suggesting a low risk of publication bias in this meta-analysis. The sensitivity analysis showed no significant changes of results after eliminating references in turn, indicating that the results were robust. Conclusion Chinese manufacturing workers, mainly young adult males, are exposed to non-Gaussian noise at high levels for a long time and have a high prevalence of NIHL. Compared to workers exposed to Gaussian noise, those exposed to non-Gaussian noise suffer from more serious hearing loss.
RESUMEN
This study was carried out to assess work ability of manufacturing workers and managerial workers. Subjects were 446 manufacturing workers and 278 managerial workers employed in Gumi industrial complex and the observation period was for 1 month(February to March), 1995. In this study, as a questionnaire for the assessment of work ability, we used the work Ability Index(WAI) which was developed by Institute of Occupational Health in Finland. Major findings obtained from this study were as follows; WAI was poor in lower economic condition, shift work, irregular diet group(p < 0.05). There were no evident trends of WAI in sex, educational level, obesity index, exercise, smoking, and alcohol drinking. In the groups of sensitive to perception of stress, other industrial classification except textile and electronics, the more than 9 hours work, the evident trends of poor WAl were observed(p<0.01). In the groups of 30-39 years old, 40-49 years old, unmarried, high school, shift work, standard body weight, and regular diet, WAl between manufacturing workers and managerial workers was significantly different(p<0.01) and WAI of managerial worker was worse than that of manufacturing worker.