Priorities for occupational noise in Britain

Regulation of occupational exposure to noise in Britain for 50 years has reduced risk. However, statistics from around the globe (and in Britain alone) suggest that the range in harm is between around zero and more than 1 in 4 workers exposed to high noise. The uncertainty in statistics and the potential high incidence and prevalence of harm justifies investigation. In Britain, we will investigate the current risk of occupational hearing loss and the effectiveness of current noise control measures. We propose to gather data during inspections of industries that are known to have high levels of workplace noise. Finding high incidence of hearing damage will indicate a failure of immediate management of risk and likely result in enforcement action. We propose to review employers' control of noise propagation in the workplace through use and maintenance of noise controls supplied with machines and supplemented with acoustic barriers and noise havens. We propose to review suppliers design and build of noise control into their products and their reported noise emissions for noisiest typical use. We are looking to benefit from the experience of our global counterparts before finalising our plans.

Workplace noise exposure and the prevalence and 10-year incidence of age-related hearing loss

There is paucity of population-based data on occupational noise exposure and risk of age-related hearing loss. Therefore, we assessed cross-sectional and longitudinal associations of past workplace noise exposure with hearing loss in older adults. At baseline, 1923 participants aged 50+ years with audiological and occupational noise exposure data included for analysis. The pure-tone average of frequencies 0.5, 1.0, 2.0 and 4.0 kHz (PTA0.5-4KHz) >25 dB HL in the better ear, established the presence of hearing loss. Participants reported exposure to workplace noise, and the severity and duration of this exposure. Prior occupational noise exposure was associated with a 2-fold increased odds of moderate-to-severe hearing loss: multivariable-adjusted OR 2.35 (95% CI 1.45–3.79). Exposure to workplace noise for >10 years increased the odds of having any hearing loss (OR 2.39, 95% CI 1.37–4.19) and moderate-to-severe hearing loss (OR 6.80, 95% CI 2.97–15.60). Among participants reporting past workplace noise exposure at baseline the 10-year incidence of hearing loss was 35.5% versus 29.1% in those who had no workplace noise exposure. Workplace noise exposure was associated with a greater risk of incident hearing loss during the 10-year follow-up: multivariable-adjusted OR 1.39 (95% CI 1.13–1.71). Prior occupational noise exposure was not associated with hearing loss progression. Workplace noise exposure increased the risk of incident hearing loss in older adults. Our findings underscore the importance of preventive measures which diminish noise exposure in the workplace, which could potentially contribute towards reducing the burden of hearing loss in later life.

Health Effects of Occupational Noise

Purpose of Review Workplace noise negatively impacts health, and noise-induced hearing loss is the most common work-related disease in many countries. Occupational noise may also cause cardiovascular disease, and there is epidemiologic evidence on the non-auditory effects of noise. This paper aims to briefly present and summarize the latest evidence on the auditory and non-auditory health effects of occupational noise exposure from the last 5 years. Recent Findings Two systematic reviews assessing the cardiovascular effects of occupational noise exposure were published in the last year. Our own recent review found convincing evidence of an association between occupational noise exposure > 80 dB(A) and hypertension and a dose-response relationship between noise exposure and hypertension risk. Another review of cardiovascular disease conducted by the World Health Organization (WHO) and the International Labour Organization (ILO) found an increased risk of incident ischemic heart disease at noise exposures ≥ 85 dB(A). Recent reviews on work-related injuries, diabetes, acoustic neuroma, and pregnancy outcomes also find noise-related associations. Summary Evidence of an association between occupational noise and cardiovascular outcomes was recently evaluated. We found the risk of hypertension increases with a clear dose-response relationship at noise levels > 80 dB(A). The WHO/ILO review highlights the lack of quality research including women. Additional high-quality research on epigenetic effects, oxidative stress, work-related injuries, diabetes, acoustic neuroma, and pregnancy outcomes is also needed. Urgently needed (increased) measures of workplace noise reduction will reduce the incidence of noise-induced hearing loss and help prevent cardiovascular diseases, especially hypertension.

High-Frequency Audiometry in Women with and without Exposure to Workplace Noise

For this study, high-frequency audiometry was used to compare the hearing thresholds, with respect to age, among women exposed to noise in their working environment, as well as those not exposed to such noise. The cohort comprised 243 women (average age 36.2 years), of which 88 women were employed in a noisy (LAeq,8h 85–105 dB) workplace, while 155 women did not experience noise. Age categories were determined according to the World Health Organization (Geneva, Switzerland). Hearing thresholds were measured at frequencies of 0.125–16 kHz. Higher hearing thresholds were found in the youngest age groups (18–29 and 30–44 years) among those exposed to noise, as compared to those who were not. The difference in hearing thresholds between the exposed and unexposed groups increased with age, as well as with the frequencies. The highest difference in hearing thresholds for these age categories was measured at 11.25 kHz. The oldest age group (45–63 years) exposed to noise showed lower hearing thresholds than the unexposed group at all frequencies from 4 kHz to 16 kHz. High-frequency audiometry can be used for the early detection of increased hearing thresholds at high frequencies. High-frequency audiometry could be included in preventive programs, especially for younger people exposed to noise, in order to enable earlier detection of noise-induced hearing loss.

High-Frequency Audiometry for Early Detection of Hearing Loss: A Narrative Review

The WHO considers hearing loss to be a major global problem. A literature search was conducted to see whether high-frequency audiometry (HFA) could be used for the early detection of hearing loss. A further aim was to see whether any differences exist in the hearing threshold using conventional audiometry (CA) and HFA in workers of different age groups exposed to workplace noise. Our search of electronic databases yielded a total of 5938 scientific papers. The inclusion criteria were the keywords “high frequency” and “audiometry” appearing anywhere in the article and the participation of unexposed people or a group exposed to workplace noise. Fifteen studies met these conditions; the sample size varied (51–645 people), and the age range of the people studied was 5–90 years. Commercial high-frequency audiometers and high-frequency headphones were used. In populations unexposed to workplace noise, significantly higher thresholds of 14–16 kHz were found. In populations with exposure to workplace noise, significantly higher statistical thresholds were found for the exposed group (EG) compared with the control group (CG) at frequencies of 9–18 kHz, especially at 16 kHz. The studies also showed higher hearing thresholds of 10–16 kHz in respondents aged under 31 years following the use of personal listening devices (PLDs) for longer than 5 years. The effect of noise-induced hearing loss (NIHL) first became apparent for HFA rather than CA. However, normative data have not yet been collected. Therefore, it is necessary to establish a uniform evaluation protocol accounting for age, sex, comorbidities and exposures, as well as for younger respondents using PLDs.

Frontal Electroencephalogram Alpha Asymmetry during Mental Stress Related to Workplace Noise

This study aims to investigate the effects of workplace noise on neural activity and alpha asymmetries of the prefrontal cortex (PFC) during mental stress conditions. Workplace noise exposure is a pervasive environmental pollutant and is negatively linked to cognitive effects and selective attention. Generally, the stress theory is assumed to underlie the impact of noise on health. Evidence for the impacts of workplace noise on mental stress is lacking. Fifteen healthy volunteer subjects performed the Montreal imaging stress task in quiet and noisy workplaces while their brain activity was recorded using electroencephalography. The salivary alpha-amylase (sAA) was measured before and immediately after each tested workplace to evaluate the stress level. The results showed a decrease in alpha rhythms, or an increase in cortical activity, of the PFC for all participants at the noisy workplace. Further analysis of alpha asymmetry revealed a greater significant relative right frontal activation of the noisy workplace group at electrode pairs F4-F3 but not F8-F7. Furthermore, a significant increase in sAA activity was observed in all participants at the noisy workplace, demonstrating the presence of stress. The findings provide critical information on the effects of workplace noise-related stress that might be neglected during mental stress evaluations.

Annoyance among Staff and Noise Level in a Tertiary Care Hospital in New Delhi, India: A Pilot Study

Introduction: In India, an area of not less than 100 metres around a hospital is considered a silence zone, with guidelines restricting noise levels at 50dBA during daytime and 40dBA during the night. Annoyance is a known effect of noise exposure. Objectives: To determine the feasibility of an extensive study on noise in the hospital, annoyance in staff due to hospital noise and its associated factors. Methods: Noise data was collected from 3 sites, using a Digital Integrating Sound Level Meter, LutronSL-4035SD(ISO-9001,CE,IEC1010) meeting IEC61672 standards. Stratified random sampling of staff was done on basis of noise exposure. A pre-designed, semi-structured questionnaire collected information on sociodemographic and work profile. Annoyance was measured using standardized general purpose noise reaction questionnaire (ISO-TS/ 15666). Data was analysed in SPSS. Result: Laeq ranged from 56dB in nephrology ward to 89.2dB at OPD atrium. Maximum noise level was 98.6dB in OPD atrium and 86.1dB in nephrology ward. Levels at night in ward were higher than during day time. 24 (53.3%) of the staff said their workplace is noisy, while 26(57.8%) were annoyed by workplace noise. Annoyance due to hospital noise was associated with age (p=0.003), duration of work in hospital per week (p=0.04), duration of work in current department (p=0.007), noise level (p=0.04) and workplace distance from arterial road (p=0.02). Conclusion: Hospital noise levels are higher than recommended levels for sensitive zones as per national guidelines and exceed levels inside wards as stipulated by WHO. More than half the study population were annoyed by workplace noise indicating need for interventions. A study throughout the hospital to study noise levels and annoyance among staff following similar methodology is feasible and necessary.

Actual problems of hygienic assessment of electromagnetic fields and noise in magnetic resonance imaging departments

The increasing use of MRI equipment increases the number of medical and technical personnel at risk of exposure to EMF and workplace noise. Existing domestic and foreign and regulatory documents defining controlled indicators, permissible exposure levels, control methods need adjustments that require additional research.

Acoustic pressure contributions of a combine harvester’s thresher drum to the overall workplace noise situation

This paper analyzes the magnitude of the acoustic pressure contribution of a combine harvester’s thresher drum to the overall noise situation with the goal of providing the regulatory parameters for the workplace conditions. In the course of the current research the velocity and pressure graphics for the airflow on the parts of a rotating thresher drum as well as the sound intensity parameters by frequency spectra and sound pressure magnitudes were calculated.