Cumulative Noise Research Articles

Computation of Variable Noise Reduction System Efficiency for Supersonic Civil Aircraft During Takeoff

The noise of next-generation supersonic civil aircraft can become a significant nuisance for the population in the vicinity of airports. This study investigates the efficiency of the noise control approach for a notional supersonic civil aircraft at takeoff, based on the implementation of a variable noise reduction system (VNRS) with thrust control. Noise levels are computed with a decoupling approach, where the engine noise data and the flight trajectory are calculated independently. It is shown that implementation of the VNRS for the supersonic civil aircraft could lead to a reduction in the certification noise levels at the lateral and flyover measurement points by about 4 EPNdB. The effect of VNRS on noise levels for two allowable positions of the lateral certification point (on the sideline and on the extended runway centerline) is considered and compared for the first time. It is found that the cumulative noise reduction at the flyover and lateral certification point due to the VNRS is larger by 0.8 EPNdB for the position of the lateral certification point on the sideline than for the position on the extended runway centerline.

Association between individual occupational noise exposure and overweight/obesity among automotive manufacturing workers in South China

BackgroundOccupational noise has been associated with numerous adverse health outcomes. However, limited evidence exists regarding its association with obesity. We aim to investigate the effect of occupational noise exposure on the risk of overweight/obesity among workers, providing scientific evidence for the prevention and management of overweight/obesity in the occupational population.MethodsThis study included 3427 participants from two factories in Guangzhou, China. Individual occupational noise exposure levels were assessed using cumulative noise exposure (CNE). Body mass index (BMI) data were obtained from physical examinations. Linear and logistic regression models, restricted cubic spline, as well as subgroup analyses, were used to explore the association.ResultsIn continuous models, each 1 dB-year increase in CNE was significantly associated with a 0.03 (95% confidence interval (CI): 0.00, 0.05) kg/m² increase in BMI. In categorical models, higher CNE levels were significantly associated with BMI (β = 0.54, 95% CI: 0.16, 0.92) and overweight/obesity (odd ratio (OR) = 1.57, 95%CI: 1.21, 2.04). Restricted cubic splines (RCS) analysis demonstrated a linear dose-response relationship between CNE and overweight/obesity (Pfor overall=0.013, Pfor non-linear=0.175). Additionally, shift and night work were identified as critical moderating factors, with a stronger association observed among workers engaged in shift and night work.ConclusionOccupational noise exposure is positively associated with overweight/obesity, particularly among those engaged in shift and night work. Thus, enhancing noise source management and promoting awareness among workers for prevention are imperative.

Tinnitus prevalence and associations with leisure noise exposure among Canadians, aged 6 to 79 years

Objective To examine the association between individual, cumulative leisure noise exposure (CLNE), acceptable yearly exposure (AYE) and tinnitus among a nationally representative sample of Canadians. Design In-person household questionnaires were used to evaluate leisure noise exposure across age, sex, household income and tinnitus: ever experienced, previous year, frequent, bothersome. High (≥85 dBA, LEX), low (<85 dBA, LEX) CLNE and AYEs were defined according to occupational limits. Study sample A randomised sample of 10,460 respondents, aged 6–79, completed questionnaires between 2012 and 2015. Results: Tinnitus prevalence was highest among young adults and teenagers (50% for both). Frequent and bothersome tinnitus afflicted one-third and 18.1% of Canadians, respectively. Men had higher tinnitus prevalence while women had increased bothersome tinnitus. For most ages, elevated tinnitus odds ratios (ORs) were associated with: (1) high, low CLNE and AYEs ≥1 and, (2) high exposure from individual sources: loud home/car stereo listening, power tools, gasoline engines, highway motorcycle/snowmobile driving. Loud personal listening device usage was associated with tinnitus ORs doubling (ages 6–11) and ≥5 or < 5 years of loud usage, with increased tinnitus ORs (ages 12–19). Conclusion Community and/or school-based educational outreach would be beneficial to increase awareness of loud leisure noise exposure and tinnitus.

Association of Occupational Noise Exposure and Extended High-Frequency Hearing Loss in Young Workers With Normal Hearing.

Studies on the relationship between occupational noise exposure and extended high-frequency (EHF) hearing loss are limited. This study investigated the relationship between occupational noise exposure and EHF hearing loss in workers exposed to noise as measured by sound pressure level, exposure duration, and kurtosis to help provide a basis for early detection and prevention of hearing loss in noise-exposed workers. A cross-sectional survey was conducted among 602 participants with 472 noise-exposed workers and 130 non-noise-exposed controls. General demographic characteristics, noise exposure data, and hearing thresholds at conventional frequencies (0.25 to 8 kHz) and EHF (9 to 16 kHz) were collected and analyzed. Linear mixed-effects model analyses between hearing thresholds of EHF and noise exposure indicators including the 8-h equivalent continuous A-weighted sound pressure level (LAeq,8h), cumulative noise exposure (CNE), and kurtosis-adjusted CNE (CNE-K) were conducted. Among the 602 participants included in the analysis, 472 individuals (78.4%) were occupationally exposed to noise exposures ≥75 dBA. Significant differences (p < 0.05) were observed in sex, exposure duration, LAeq,8h, CNE, and CNE-K between the noise-exposed group and the nonexposed group. The mean hearing thresholds for all tested extended high frequencies ranging from 9 to 16 kHz were significantly higher in the noise-exposed group than in the nonexposed group (p < 0.05). The mean hearing thresholds of subjects in different groups of LAeq,8h exposures were generally stable with little variance in the conventional frequencies (0.25 to 8 kHz) but differed in the EHF range. Moreover, EHF hearing loss appeared to be most prominent in the subjects exposed to noise with 80 dBA < LAeq,8h ≤ 85 dBA. After the combination of the sound pressure level, exposure duration, and kurtosis by using the noise exposure indicators CNE and CNE-K, the subjects at the different noise exposures showed significant differences in hearing thresholds at EHF (p < 0.05). Linear mixed-effected model analyses showed that the CNE-K was the best to indicate noise-induced hearing loss among the three noise exposure indicators at EHF. The results indicate that the EHF hearing threshold testing is more sensitive to identifying early occupational noise-induced hearing loss than conventional audiometry. The CNE-K, an indicator combining noise energy, exposure duration, and kurtosis, is a more comprehensive and effective method for assessing the risk of EHF hearing loss due to occupational noise exposure.

Combined effects of benzene, toluene, xylene, ethylbenzene, and styrene exposure on hearing loss mediated by oxidative stress at realistic low levels

The link between benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) exposure and hearing loss (HL) is not well-established. This study investigated 1694 petrochemical workers in southern China to examine the effects of BTEXS urinary metabolites on auditory function, considering oxidative stress (OS) as a potential cause. Using generalized linear models, elastic net regression, and quantile g-computation, we evaluated the single and combined effects of BTEXS, OS indicators, and HL. Subgroup analysis explored interactions between BTEXS and cumulative noise exposure (CNE), while mediation analysis assessed OS's role in BTEXS-related HL. Positive associations were found between hippuric acid (HA) and HL (OR = 1.20, P < 0.05) and high-frequency hearing loss (HFHL) (OR = 1.22, P < 0.05). The ENET model linked 3&4-methylhippuric acid (3&4-MHA) with increased HFHL risk. The qgcomp model showed a 23% increased HL risk and a 20% increased HFHL risk per quartile increase in BTEXS exposure. Toluene metabolites (SBMA and HA) were significant contributors to HL, HFHL, and speech-frequency hearing loss (SFHL). Higher BTEXS SBMA, MA and HA levels exacerbated HL risk in workers exposed to CNE. Interaction analysis revealed synergistic effects between tt-MA and other metabolites on HFHL risk. Total SOD (TSOD) significantly mediated the BTEXS-HL relationship. These findings highlight a dose-effect association between BTEXS exposure and HL due to oxidative damage, with toluene metabolites being critical pollutants. BTEXS exposure also synergistically increased HL risk with noise.

Associations Between Noise Exposure Level, Noise Kurtosis, and Distortion Product Otoacoustic Emissions in Young Workers With Normal Hearing.

Growing evidence has suggested that, in addition to noise exposure level, noise temporal structure (i.e., kurtosis) plays an important role in the development of noise-induced hearing loss, while most of the relevant research has been on the results of pure-tone audiometry. This study focuses on the combined effect of noise exposure level and noise kurtosis on distortion product otoacoustic emissions (DPOAEs) in young workers with normal hearing. A cross-sectional study among young workers in manufacturing industries was conducted in Zhejiang Province, China. Individual noise exposure measurements were performed on participants to obtain an A-weighted noise exposure level normalized to 8 hr (LAeq, 8hr), cumulative noise exposure (CNE), kurtosis, and kurtosis-adjusted CNE (CNE-K). The DPOAE test was performed on the participants and DPOAE levels were obtained. The relationships between noise exposure level, kurtosis, and DPOAE levels were explored by univariate analyses. Furthermore, multivariate regression models were conducted to estimate the combined effects of exposure level and kurtosis after adjusting for age, gender, and use of hearing protection devices. The overall DPOAE curves across frequency bands presented a fluctuating downward trend with increasing frequency. Both exposure level and kurtosis were found to be associated with decreases in DPOAE levels. The multivariate regression model including CNE-K as a joint indicator of complex noise showed an increased R2 compared with the model including CNE. After adjustment for age, gender, and the use of hearing protection devices, significant effects of CNE-K on DPOAE levels were observed at 3, 4, and 5 kHz frequencies, with maximum effect presented at 4 kHz. DPOAE is a sensitive test that can detect cochlear damage in limited areas that cannot be detected by conventional audiometry. The present study provided a more comprehensive understanding of the impact of complex noise on the DPOAE levels. It also suggested that CNE-K was an effective metric in assessing DPOAE levels associated with complex noise.

Correlation between Occupational Noise Exposure and Renal Dysfunction in Male Workers

Objective: This study aimed to explore the relationship between occupational noise exposure and renal dysfunction in male workers. Methods: A total of 160 male workers (the number of people who met the inclusion criteria) who underwent health examinations in Qingdao Municipal Hospital from January 2023 to December 2023 were grouped into a noise group (80 cases) and a control group (80 cases) based on whether they engaged in noise work. We compared the differences in creatinine (CREA), cystatin C (CysC) and blood urea nitrogen (BUN) levels between the two groups. We also compared the differences in the above renal function indicators among workers with different working years in the noise group, as well as observed the relationship between renal dysfunction and noise exposure. Results: The levels of BUN, CREA and CysC in the noise group were significantly higher than those in the control group (P &lt; 0.05). The overall abnormal rate of renal function in the noise group (42.50%) was significantly higher than that in the control group (11.25%, P &lt; 0.05). The levels of BUN, CREA and CysC all significantly increased with the increase in working years (P &lt; 0.05). The noise exposure intensity and cumulative noise exposure (CNE) of the group with renal dysfunction were higher than those of the group with normal renal function (P &lt; 0.05). The area under the curve was 0.811 (95% confidence interval: 0.714–0.908), the optimal cut-off value of CNE was 96.53 dB (A) · year, the sensitivity was 89.29%, the specificity was 83.32% and the Youden index was 72.61%. Conclusion: There may be a correlation between long-term noise exposure and renal function. The intensity of noise exposure and CNE may have a certain correlation with renal function damage in occupational noise-exposed workers.

Kurtosis Assessment of Cardiovascular Disease Risk Caused by Complex Noise in Coal Mines.

This study aims to investigate the relationship between noise kurtosis and cardiovascular disease (CVD) risk while exploring the potential of kurtosis assessment in evaluating CVD risk associated with complex noise exposure in coal mines. This cross-sectional study started in April 2021 and ended in November 2022. It involved 705 coal miners selected from 1045 participants. The participants underwent questionnaire surveys, physical examinations and assessment of individual noise exposure levels in the form of LAeq.8h. Individual CVD risk was evaluated by employing the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR). Logistic regression analyses were used to analyse the effect of noise kurtosis on the risk of developing CVD and adjust for confounders to determine independent effects. Stratified analyses were applied to examine the effect of different noise characteristics on risk. In cardiovascular risk assessment using China-PAR, 637 and 68 individuals were classified as low and high risk, respectively. Notably, the group exposed to noise levels of 85-100 dB(A) exhibited a significantly higher risk than those exposed to noise levels of <85 dB(A). Regarding kurtosis (β), individuals with β < 3 had low cardiovascular risk, whereas those with β > 5 had high risk, with risk increasing alongside kurtosis. Correlation analysis indicated a strong association amongst noise kurtosis, cumulative noise exposure (CNE) and CVD risk after accounting for individual age and service duration. Logistic regression analysis identified kurtosis as the primary influencing factor for CVD risk (odds ratio = 3.46, 95% confidence interval: 1.68-7.13). Given the pervasive presence of complex noise in the coal mining industry, kurtosis can serve as a valuable supplementary parameter for adjusting CNE, thus facilitating the assessment of CVD risk associated with complex noise exposure in coal mines.

An improved evaluation method of industrial noise based on level of noise pollution and kurtosis-weighted cumulative noise exposure

While industry development has improved people's lives, industrial noise has also caused negative impacts. Industrial noise cannot be avoided in industrial environments. It is essential to accurately evaluate industrial noise. Most existing industrial noise evaluation methods consider the factors of industrial noise but ignore the factors of human perception and cannot accurately reflect the subjective auditory perception of humans. The paper proposes an industrial noise evaluation method, LCINE, based on level of noise pollution (LNP) and kurtosis-weighted cumulative noise exposure. First, statistical regression is used to determine the LNP constant based on improved Robinson's method. The consideration of both industrial noise and individual worker in improved method makes the constant suitable for evaluating industrial noise. Second, the improved LNP is combined with kurtosis to determine the intensity evaluation item. Kurtosis is used to capture the extremity of outliers and amplitude variations effectively in statistics, so kurtosis accurately reflects sound peaks and intensity here. Then, the exposure time evaluation item is determined by combining kurtosis with exposure time. Finally, the normalization method is used to allocate theweights of the intensity evaluation item and the exposure time evaluation item, which can unify the measurement units and reduce the adverse effects caused by extreme data. The superiority of LCINE is verified through methods including correlation test, paired-samples t test, partial regression sum of squares test, and subjective evaluation. The results indicate that the method LCINE can more accurately evaluate industrial noise and is more consistent with the subjective auditory perception of humans.

Noise exposure of the inner ear during robotic drilling.

Preserving the cochlear structures and thus hearing preservation, has become a prominent topic of discussion in cochlear implant (CI) surgery. Various approaches and soft surgical techniques have been described when approaching the inner ear. Robot-assisted cochlear implant surgery (RACIS) reaches the round window in a minimally invasive manner by following a trajectory of minimal trauma. This involves the drilling of a keyhole trajectory to the round window, through the facial recess, with no need for a complete mastoidectomy. It involves less drilling, less drilling time and less structural damage. A lot of attention has been paid to the structural traumatic causes of hearing loss but acoustic trauma during the exposure of the inner ear appears to be neglected topic. The aim was to measure the noise exposure of the inner ear during the robotic drilling of the mastoid and bony overhang of the round window. The results were compared with the milling in conventional cochlear implantation surgery. RACIS on fresh frozen human cadavers. The equivalent frequency-weighted and time-averaged sound pressure level LAF in dB and the noise dose in % derived from a noise damage model, both obtained during RACIS. The robotic drilling of 6 trajectories towards the inner ear were performed, including 4 trajectories through round window access and 2 trajectories through cochleostomy. The results were compared with the data of 7 cases of conventional CI surgery that have been described in literature. The induced equivalent sound pressure level LAF was determined via an accelleration sensor at the zygomatic arch and a calibration according to bone conduction audiometry. A noise dose for the whole procedure was calculated from the equivalent sound pressure level LAF and the exposure time using a noise damage model. A noise dose of 100% is considered a critical exposure limit and values above are considered potentially harmful, with the risk of hearing impairment. The maximum LAF was 82 dB during fiducial screw placement; 87 dB during middle ear access; 95 dB for the accesses through the round window and 88 dB for the accesses through cochleostomy. The noise dose due to the HEARO®-procedure was always far below the critical value of 100%. There was no acoustic trauma of the inner ear in all cases with the noise dose being smaller than 0.1% in five out of the six cases. The maximum LAF in the seven cases of conventional CI surgery was 118 dB with a maximum cumulative noise dose of 172.6%. The critical exposure limit of 100% was exceeded in three cases of conventional CI surgery. RACIS provokes significantly less acoustic trauma than conventional mastoid surgery in our findings. There were no observable differences in noise exposure levels between a cochleostomy or a round window approach where the bony overhang needed to be drilled.

A longitudinal study investigating the effects of noise exposure on behavioural, electrophysiological and self-report measures of hearing in musicians with normal audiometric thresholds

Musicians are at risk of hearing loss and tinnitus due to regular exposure to high levels of noise. This level of risk may have been underestimated previously since damage to the auditory system, such as cochlear synaptopathy, may not be easily detectable using standard clinical measures. Most previous research investigating hearing loss in musicians has involved cross-sectional study designs that may capture only a snapshot of hearing health in relation to noise exposure. The aim of this study was to investigate the effects of cumulative noise exposure on behavioural, electrophysiological, and self-report indices of hearing damage in early-career musicians and non-musicians with normal hearing over a 2-year period. Participants completed an annual test battery consisting of pure tone audiometry, extended high-frequency hearing thresholds, distortion product otoacoustic emissions (DPOAEs), speech perception in noise, auditory brainstem responses, and self-report measures of tinnitus, hyperacusis, and hearing in background noise. Participants also completed the Noise Exposure Structured Interview to estimate cumulative noise exposure across the study period. Linear mixed models assessed changes over time. The longitudinal analysis comprised 64 early-career musicians (female n = 34; age range at T0 = 18–26 years) and 30 non-musicians (female n = 20; age range at T0 = 18–27 years). There were few longitudinal changes as a result of musicianship. Small improvements over time in some measures may be attributable to a practice/test-retest effect. Some measures (e.g., DPOAE indices of outer hair cell function) were associated with noise exposure at each time point, but did not show a significant change over time. A small proportion of participants reported a worsening of their tinnitus symptoms, which participants attributed to noise exposure, or not using hearing protection. Future longitudinal studies should attempt to capture the effects of noise exposure over a longer period, taken at several time points, for a precise measure of how hearing changes over time. Hearing conservation programmes for “at risk” individuals should closely monitor DPOAEs to detect early signs of noise-induced hearing loss when audiometric thresholds are clinically normal.

Relationship Between Work-Related Noise Exposure and Cognitive Impairment: A Cross-Sectional Study in China

Background: Noise exposure and the risk of cognitive impairment are currently major public health issues. Objective: This study aimed to analyze the relationship between noise exposure and early impairment of cognitive function from the perspective of occupational epidemiology and to provide evidence for the long-term prevention and treatment of dementia in the context of aging. Methods: This study was conducted in China between May and August 2021. The independent variables were the type of hazardous factors, duration of noise exposure, perceived noise intensity, and cumulative noise exposure (CNE). The dependent variable was cognitive function, which was measured using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Multiple linear and logistic regression were used to analyze the relationship between noise exposure and cognitive function and to establish an effect curve. Results: The detection rates of cognitive dysfunction using the MMSE and MoCA were 1.1% and 36.2%, respectively. The predicted MMSE and MoCA scores showed a downward trend within the CNE value ranging from 90–140 dB.time. Each unit increase in CNE decreased cognitive function scores by 0.025 (0.037, 0.013) and 0.020 (0.037, 0.003) points,respectively. Conclusions: From the perspective of occupational epidemiology, these findings reveal a potential link between long-term noise exposure and early cognitive impairment.

Association of noise exposure with lipid metabolism among Chinese adults: mediation role of obesity indices.

Noise exposure in the workplace has been linked to a number of health consequences. Our objectives were to explore the relationship between occupational noise and lipid metabolism and evaluate the possible mediating effect of obesity indices in those relationships with a cross-sectional study design. Cumulative noise exposure (CNE) was used to measure the level of noise exposure. Logistic regression models or generalized linear models were employed to evaluate the association of occupational noise and obesity with lipid metabolism markers. Cross-lagged analysis was conducted to explore temporal associations of obesity with lipid metabolism. A total of 854 participants were included, with each one-unit increase in CNE, the values of total cholesterol/high-density lipoprotein cholesterol and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol increased by 0.013 (95% confidence interval: 0.006, 0.020) and 0.009 (0.004, 0.014), as well as the prevalence of dyslipidemia increased by 1.030 (1.013, 1.048). Occupational noise and lipid metabolism markers were all positively associated with body mass index (BMI), waist circumference (WC), a Body Shape Index (ABSI) and a Body Shape Index and Body Roundness Index (BRI) (all P < 0.05). Moreover, BMI, WC, ABSI and BRI could mediate the associations of occupational noise with lipid metabolism; the proportions ranged from 21.51 to 24.45%, 23.84 to 30.14%, 4.86 to 5.94% and 25.59 to 28.23%, respectively (all P < 0.05). Our study demonstrates a positive association between occupational noise and abnormal lipid metabolism, and obesity may partly mediate the association. Our findings reinforce the need to take practical steps to reduce or even eliminate the health risks associated with occupational noise.

Association between exposure to metalworking fluid aerosols, occupational noise and chronic kidney disease: a cross-sectional study in China

BackgroundChronic kidney disease (CKD) carries a high public health burden yet little is known about the relationship between metalworking fluid (MWF) aerosols, occupational noise and CKD. We aimed to explore the relationship between occupational MWF aerosols, occupational noise and CKD.MethodsA total of 2,738 machinists were sampled from three machining companies in Wuxi, China, in 2022. We used the National Institute for Occupational Safety and Health (NIOSH) method 5524 to collect individual samples for MWF aerosols exposure, and the Chinese national standard (GBZ/T 189.8–2007) method to test individual occupational noise exposure. The diagnostic criteria for CKD were urinary albumin/creatinine ratio (UACR) of ≥ 30 mg/g and reduced renal function (eGFR < 60 mL.min− 1. 1.73 m− 2) lasting longer than 3 months. Smooth curve fitting was conducted to analyze the associations of MWF aerosols and occupational noise with CKD. A segmented regression model was used to analyze the threshold effects.ResultsWorkers exposed to MWF aerosols (odds ratio [OR] = 2.03, 95% confidence interval [CI]: 1.21–3.41) and occupational noise (OR = 1.77, 95%CI: 1.06–2.96) had higher prevalence of CKD than nonexposed workers. A nonlinear and positive association was found between increasing MWF aerosols and occupational noise dose and the risk of CKD. When daily cumulative exposure dose of MWF aerosols exceeded 8.03 mg/m3, the OR was 1.24 (95%CI: 1.03–1.58), and when occupational noise exceeded 87.22 dB(A), the OR was 1.16 (95%CI: 1.04–1.20). In the interactive analysis between MWF aerosols and occupational noise, the workers exposed to both MWF aerosols (cumulative exposure ≥ 8.03 mg/m3-day) and occupational noise (LEX,8 h ≥ 87.22 dB(A)) had an increased prevalence of CKD (OR = 2.71, 95%CI: 1.48–4.96). MWF aerosols and occupational noise had a positive interaction in prevalence of CKD.ConclusionsOccupational MWF aerosols and noise were positively and nonlinearly associated with CKD, and cumulative MWF aerosols and noise exposure showed a positive interaction with CKD. These findings emphasize the importance of assessing kidney function of workers exposed to MWF aerosols and occupational noise. Prospective and longitudinal cohort studies are necessary to elucidate the causality of these associations.

Investigating the effects of underwater noise from two vessels on the behaviour of short-finned pilot whales

Multiple whale-watching vessels may operate around cetaceans at any one time, and targeted animals may experience underwater noise effects. We hypothesised that the cumulative noise of two vessels with low source levels (SLs) will elicit lower behavioural disturbance in short-finned pilot whales (Globicephala macrorhynchus) compared to a single vessel with a higher SL. We measured the behaviour of whales during 26 controls (stationary vessel >300 m) and 44 treatments off Tenerife (Canary Islands, Spain). Treatments consisted of vessel approaches mimicking whale-watch scenarios (distance ∼60 m, speed 1.5 kn). Approaches with two simultaneous vessels, with maximum cumulative mid and low-frequency (0.2–110 kHz) weighted source levels (SLsMF-LF) 137–143 dB, did not affect mother-calf pairs’ resting, nursing, diving, respiration rate or inter-breath interval. However, a louder single vessel approach with twin petrol engines at SLsMF-LF 139–151 dB significantly decreased the proportion of time resting for the mother. The results suggest that if a single or two vessels are present, if the cumulative SL is < 143 dB, the behavioural disturbance on the whales will be negligible. By examining noise effects from multiple vessels on the behaviour of pilot whales, the importance of incorporating a noise threshold into whale-watching guidelines was emphasised.

Risk analysis of noise-induced hearing loss of workers in the automobile manufacturing industries based on back-propagation neural network model: a cross-sectional study in Han Chinese population

ObjectivesThis study aims to predict the risk of noise-induced hearing loss (NIHL) through a back-propagation neural network (BPNN) model. It provides an early, simple and accurate prediction method for NIHL.DesignPopulation...

Do Surgical Smoke Evacuators Increase the Risk of Hearing Loss for Operative Personnel During Routine Adenotonsillectomy Surgery?

Aerosol mitigation equipment implemented due to COVID-19has increased noise levels in the operating room (OR) during otolaryngological procedures. Intraoperative sound levels may potentially place personnel at risk for occupational hearing loss. This study hypothesized that cumulative intraoperative noise exposures with aerosol mitigation equipment exceed recommended occupational noise exposure levels. Sound levels generated by the surgical smoke evacuator (SSE) during adenotonsillectomy were measured using a sound level meter and compared to surgery without SSE. Thirteen adenotonsillectomy surgeries were recorded. Mean sound levels with the SSE were greater than the control (72 ± 3 A-weighted decibels (dBA) vs. 68 ± 2 dBA; p=0.015). Maximum noise levels during surgery with SSE reached 82 ± 3 dBA. Surgeons performing adenotonsillectomy with aerosol mitigation equipment are exposed to significant noise levels. Intraoperative sound levels exceeded international standards for work requiring concentration. Innovation is needed to reduce cumulative OR noise exposures.

Variations in the Cadherin 23 Gene Associated With Noise-Induced Hearing Loss.

The relationship between CDH23 gene variants and NIHL is unclear. This study investigates the association between cadherin 23 (CDH23) gene variants and noise-induced hearing loss (NIHL). This is a case-control study. Workers who were exposed to noise from a steel factory in North China were recruited and divided into two groups: the case group (both ears' high-frequency threshold average [BHFTA] ≥40dB) and the control group (BHFTA ≤25 dB). This study used the generalised multifactor dimensionality reduction method to analyse the association among 18 single-nucleotide polymorphisms (SNPs) in CDH23 and NIHL. Logistic regression was performed to investigate the main effects of SNPs and the interactions between cumulative noise exposure (CNE) and SNPs. Furthermore, CNE was adjusted for age, gender, smoking, drinking, physical exercise and hypertension. This study recruited 1,117 participants. The results showed that for rs11592462, participants who carried the GG genotype showed an association with NIHL greater than that of those who carried the CC genotype. Accordingly, genetic variation in the CDH23 gene could play an essential role in determining individual susceptibility to NIHL. Genetic variations in the CDH23 gene may play an important role in determining individual susceptibility to NIHL. These results provide new insight into the pathogenesis and early prevention of NIHL.

Statistical estimation of noise induced hearing loss among the drivers in one of the most polluted cities of India

In the present study, an attempt has been made to assess the impact of vehicular noise upon the 3-wheeler tempo drivers and to know whether there is any relationship between hearing loss and cumulative noise exposure. For this purpose, 3-wheeler tempo drivers (Exposed group) and non-commercial light motor vehicle car drivers (Unexposed group) were chosen as study subjects. Three traffic routes were selected to assess the noise level during waiting and running time in the exposed and unexposed groups. Among all three routes, the highest mean noise level (Leq) was observed on the Chowk to Dubagga route for waiting and en-route noise measurement. It was measured as 84.13 dB(A) and 86.36 dB(A) for waiting and en-route periods of 7.68 ± 3.46 and 31.05 ± 6.6 min, respectively. Cumulative noise exposure was found to be significantly different (p < 0.001) in all age groups of exposed and unexposed drivers. Audiometric tests have been performed over both exposed and unexposed groups. The regression analysis has been done keeping hearing loss among tempo drivers as the dependent variable and age (years) and Energy (Pa2 Hrs) as the independent variable using three different criteria of hearing loss definitions, i.e., World Health Organization, National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Administration criteria. Among these three criteria, the NIOSH criterion of hearing loss best explained the independent variables. It could explain the total variation in dependent variable by independent variable quite well, i.e., 68.1%. The finding showed a linear relationship between cumulative noise exposures (Pa2 Hrs) and the exposed group's hearing loss (dB), i.e., hearing loss increases with increasing noise dose. Based on the findings, two model equations were developed to identify the safe and unsafe noise levels with exposure time.

Environmental Risk Factors, Protective Factors, and Biomarkers for Hearing Loss: An Umbrella Review.

We aimed to investigate the potential environmental risk factors, protective factors, and biomarkers of hearing loss (HL), and establish a hierarchy of evidence. Embase, PubMed, Cochrane Library, and Web of Science electronic database from inception to June 1, 2023. We included meta-analyses of observational studies of associations between HL and environmental risk factors, protective factors, or biomarkers. We calculated summary effect estimates, 95% confidence interval, heterogeneity I2 statistic, 95% prediction interval, small study effects, and excess significance biases. Of the 9211 articles retrieved, 60 eligible articles were included. The 60 eligible articles identified 47 potential environmental risk and protective factors (N = 4,123,803) and 46 potential biomarkers (N = 173,701). Evidence of association was convincing (class I) for rheumatoid arthritis (RA) and every 1 cm increase in height. Evidence of association was highly suggestive (class II) for human immunodeficiency virus (HIV), diabetes, cumulative noise exposure (CNE), smoking, congenital cytomegalovirus (CMV) infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and alopecia areata (AA). In this umbrella review, RA, every 1 cm increase in height, HIV, diabetes, CNE, smoking, congenital CMV infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and AA were strongly associated with HL.