Although the adverse auditory effects of noise have been the focus of occupational health research for decades, little is known about the nonauditory health effects that result from noise exposure. The focus of this research was the nonauditory health effects of exposure to commercial aircraft noise (CAN) overflights. It was theorized that CAN exposure resulted in an ongoing stress-response that had the potential to be harmful to human health over time. Two aspects of CAN were considered; the sound level intensity (dBA), and the frequency of overflights. Data were collected by a stratified random sampling design in the CAN exposed neighborhoods of Eagan, St. Paul, Minneapolis, and Bloomington, and in control communities of Shoreview and Mounds View, all located in Minnesota (n=4000). A written questionnaire was used to measure; (1) health (MOS-36 Scale), (2) behavioral and emotional coping strategies, (3) noise sensitivity, (4) annoyance levels, and (5) demographic data. Aircraft noise levels and overflight data were obtained in cooperation with the Metropolitan Airport Sound Abatement Commission. Results showed significantly higher stress levels and lower health measures by CAN exposure type. These findings occurred primarily in communities exposed to high frequencies of aircraft overflights. Multivariate analysis revealed significant reductions for the three main health measures of General Health (GH), Sense of Vitality (Vitality), and Mental Health (MH), based on CAN exposure type. Post-hoc contrast analysis indicated that GH, Vitality, and MH scores were worst with high frequency of overflights. Behavioral copers had significantly fewer stress symptoms and used fewer stress medications than non-behavioral copers. Non-normalized emotional copers had significant negative associations with Gil, Vitality, and MH; however, these correlations were weak. Noise sensitivity levels were not significantly different among the CAN exposed communities; however noise annoyance levels were significantly higher than controls, and were the highest with high frequency of overflights. Finally, multivariate analysis of covariance indicated significant reduction for health measures based on CAN exposure types after adjusting for all effect modifiers (covariates) in the study. Vitality was the most consistently impacted by CAN exposure, and this was particularly the case for subjects exposed to high frequency of aircraft overflights. / Graduation date: 1996

The magnitude of noise pollution is fast-growing worldwide. Environmental noise has been linked with several non-auditory health impacts, including annoyance, sleep disturbance, cardiovascular diseases and impaired cognitive performance. Also, environmental noise exposure is associated with increased reported psychological symptoms, prolonged healing time of patients and poorer performance of staff in hospitals. Hong Kong has been suffering from environmental noise for years, especially transportation noise, but lack of relevant local studies to support public health intervention. This review is attempted to summarize three governmental study reports and overseas studies on the relationship between noise and non-auditory effects. Also data on noise complaints will be briefly analysed as a supplement. It is ascertained that noise pollution and noise-induced annoyance and sleep disturbance are prevalent in Hong Kong. Also, noise mapping and subjective auditory effect scales are already available. Noise complaint level in Hong Kong is generally lower than levels in London and New York City, but is probably underestimated. Future studies are needed to emphasize on noise exposure in particular areas and vulnerable populations / published_or_final_version / Public Health / Master / Master of Public Health

Thesis (MTech (Omgewingsgesondheid))--Cape Peninsula University of Technology, 2011. / Occupational related diseases (ORD) which result in permanent disability are compensable in South Africa. During the 2005/6 – 2007/8 financial years compensation for ORD’s totalled approximately R200 million per annum of which this study indicated, R92 milllion on average possibly related to hearing loss. This expense must surely result in negative financial consequences for both the South African government and employers. The manner in which compensation for hearing loss relating to the work place, is to be determined, was changed by Instruction 171 published in the Government Gazette dated 16 November 2001. A baseline audiogram is required for every employee who enters a noise zone during the course of employ and Instruction 171 specified that the percentage hearing loss has to be used to determine this baseline audiogram. A baseline audiogram, which is valid for the total working career of an employee, is used to monitor the hearing status of employees for purposes of possible future compensation. It consequently serves as a reference point from which hearing threshold shifts (HTS) are determined. The significance of the accuracy of this test is thus evident.Prior to the implementation of Instruction 171, various audiometric measuring tools were, in accordance with South African Standards, used in industry for purposes of hearing conservation. These measuring tools referred to above were used for various purposes which included, the determination of; compensable HL, the need for diagnostic procedures, when HL had to be reported to the Department of Labour as “an incident” and the efficiency of a hearing conservation program. With implementation of Instruction 171, these various measuring tools were reduced to a single tool namely the PLH.Naturally the accuracy of PLH determination is also important to employees as it may affect possible compensation of an individual’s hearing loss. Considering the significance of baseline audiograms for purposes of compensation, the following questions arose in this study; (i) does PLH, in its current format, measure the hearing threshold (HT) sufficiently accurately to (a) establish the baseline audiogram, (b) monitor HL for purposes of compensation, and (ii) is the PLH, as currently determined, suitable to identify further diagnostic procedures for purposes of hearing conservation?A more accurate PHL calculation procedure would be to the advantage of all parties concerned. A database which included baseline audiograms of 1101 respondents was studied to determine if the PLH, in its current format, was suitable to comply with the needs pertaining to industrial audiometry. The respondents were employees working in noise zones at various industries, located in the Western Cape and were all tested in accordance with South African audiometry standards.The current PLH determination procedure was studied and current audiometry baseline test results were reconstructed in a manner to calculate an alternative PLH. This reconstructed PLH was consequently used to determine a new B-baseline audiogram. StatSoft Statistica, software was used to statistically compare the current baseline audiogram with the B-baseline audiogram. The study revealed that the B-baseline audiogram succeeded to on average produce a 17% improvement (more accurate) in the determination of the PLH. The PLH of the B-baseline audiogram can thus be regarded as more representative of the true HT of employees.Based on the results of this study it is recommended that the current determination of the PLH used to establish the baseline, be amended. The proposed amendment (B-baseline audiogram) still uses the HT of the two tests done in accordance with Instruction 171 and no amendment of the test procedure is thus required. As the PLH of the baseline and the diagnostic baseline audiogram is currently used for compensation purposes, it is recommended that the B-baseline method be used for both the baseline and diagnostic baseline audiograms.

Thesis (M. Tech.) - Central University of Technology, Free State, 2006 / Occupational noise affects industries in many countries around the world, and there is strong evidence from previous research linking it to noise-induced hearing loss (NIHL). More than 30 million workers in the United States of America alone were exposed to hazardous noise at the workplace before 1998. In South Africa, workers are not supposed to be exposed to a noise rating limit at or above 85dB(A). Abattoir employees are subjected to high noise levels when compared to the occupational noise rating limit of 85dB(A). Noise is generated from various mechanised and manual processes and activities in the abattoir during the slaughter of different animal species. Noise sources include conveyers, circular saws, air conditioners and pumps, pneumatic and other mechanical equipment. The aim of this study was to characterise noise exposure in different grades of abattoirs during the slaughter of cattle and sheep. The grading of abattoirs was previously done according to Grade A-E. Grade A-C is now referred to as high throughput abattoirs while Grade D and E are referred to as low throughput abattoirs. Personal and environmental noise exposure levels of workers in Grade A, C and D abattoirs in the Free State were therefore investigated. Noise measurements were done in accordance with the methods stipulated in the South African National Standards (SANS) Code of Practice 10083. Environmental and personal sampling were conducted with a calibrated Type 1 Quest integrated sound level meter (ISLM) and a Quest noise dosimeter respectively. Calibration was checked before and after taking measurements to ensure reliability and validity of results. The average noise exposure level in the high throughput abattoirs was above the recommended standard of 85dB(A). In the low throughput abattoirs the noise exposure levels were below this level. There were no statistically significant differences between the noise exposure levels during the slaughter of different species (P>0.05), or between Grade A and Grade C (P>0.05). There was a statistically significant difference (P<0.05) however between Grade A and Grade D noise exposure levels. The results indicate that workers in Grade A and C abattoirs are exposed to unacceptable noise levels. Further research is recommended to include all categories of abattoirs and to determine the impact of noise exposure on the worker’s hearing in order to develop strategies to protect employees from the effects of excessive exposure to noise.

Submitted in fulfillment of the requirements for the degree of Doctor of Technology: Quality Management, Durban University of Technology, 2014. / Hearing conservation in the industrial setting has mainly focussed on the harmful effects of noise exposure on the auditory system. This study investigated the co-exposure to noise and ototoxic chemicals on the auditory system of workers engaged by labour brokers. It examined the adequacy of current occupational health and safety legislation to address chemically induced hearing loss and makes recommendations at a policy level to protect workers’ hearing at the workplace. This study is an exploratory cross-sectional field case study in an industrial setting. A sample of 300 workers was drawn from a rubber factory involved in the manufacture of components for the motor, shoe and plumbing industries in the metropolitan area of Durban. Purposive sampling was undertaken amongst a cohort of day shift workers which constituted the research subjects. The research tools used in the study included the completion of the NoiseChem questionnaire, conducting pure tone audiometric testing on research subjects, monitoring noise exposure levels and performing chemical air monitoring of the ambient environment. This study confirms that a segment of the research subjects were exposed to both ototoxic chemicals and noise. Chemical exposure of research subjects was within legal permissible limits in most instances. Noise exposure exceeded the noise rating limit of 85 dBA in certain work areas. Multiple regression analysis revealed that there was a slight trend towards co-exposure to chemicals and noise being risk factors for hearing loss with an odds ratio of 1.7 (95% CI = 0.34 – 8.57) but the p value was not significant. No significant association with hearing loss was evident for workers exposed to chemical only with odds ratio of 0.41 (95% CI = 0.11 – 1.53, p = 0.19) and noise only with odds ratio of 0.87 (95% CI = 0.32 – 2.31, p = 0.78). The study indicated that workers exposed to both ototoxic chemicals and noise may be more susceptible to hearing loss in their current jobs. The study draws attention to policy gaps in the Occupational Health and Safety Act and proposes changes to address the shortcomings. / D

The study investigated the feasibility of including DPOAEs in the annual medical surveillance test battery for the identification of NIHL in a group of employees in a manufacturing industry in KwaZulu-Natal. Feasibility was investigated by exploring the sensitivity, specificity and predictive efficiency of DPOAEs, the ability of DPOAEs to detect subtle noise-induced cochlea changes, the test-retest reliability of DPOAEs and lastly, the duration of time taken to conduct the DPOAE test bilaterally. A cross-sectional and repeated measures within-in participant design was utilized in the study. A purposive convenience sampling technique was used, as well as a stratified sampling approach in order to realize objective two of the study. The study consisted of 60 participants, which were further stratified into four test groups, i.e. Group A: 0-3 years, Group B: 3.1-6 years and Group C: 6.1-9 years and Group D: 9.1-13 years of working within the beverage manufacturing industry. A high sensitivity and negative predictive value was reported in the current study, suggesting that DPOAEs may be able to identify those who present with subtle cochlea changes as a result of exposure to occupational noise. The sensitivity of DPOAEs was 100% at 1, 2, 4, 6 and 8kHz in the right ear and at 4 and 6kHz in the left ear. The specificity of DPOAEs in the current study ranged between 55%-97% across the frequency range in the right ear and 49%-88% in the left ear. A negative predictive value of 100% was obtained bilaterally across the frequency range, except at 8kHz in the left ear. Visual inspection of the DPgram in the current study revealed a bilateral reduction in DPOAE amplitudes for all test groups in the high frequency region of the DP-Gram, namely, 5477Hz and 7303Hz, in the absence of a statistically significant difference (p>0.05). A greater frequency range appears to be affected in this group of workers, indicating that the type of noise, namely, impulse noise, may result in cochlea changes. Corresponding changes on the pure tone audiogram were not observed, however, noise notch configurations were observed for the groups with a longer history of noise exposure. This was not seen bilaterally as is typically expected with NIHL. Good test-retest reliability across the frequency range obtained in the current study further indicates the feasibility of including DPOAEs in the annual medical surveillance test battery. Additionally, the current study calculated an average of 86 seconds (1 minute 26 seconds) to conduct the DPOAE test bilaterally, confirming that DPOAEs are a quick test to administer. The findings of this study suggest that DPOAEs may be used to monitor early subtle noise-induced cochlea changes for workers exposed to noise in the beverage manufacturing industry as part of the annual medical surveillance test battery. / Thesis (M.Comm.Path.)-University of KwaZulu-Natal, Westville, 2013.