Objective To test a kurtosis-adjusted cumulative noise exposure (CNE) metric for use in evaluating the risk of hearing loss among workers exposed to industrial noises. Specifically: to evaluate if the kurtosis-adjusted CNE (1) provides a better association with observed industrial noise-induced hearing loss; (2) provides a single metric applicable to both complex (non-Gaussian) and continuous or steady-state (Gaussian) noise exposures for predicting noise induced hearing loss (dose-response curves). Design Audiometric and noise exposure data were acquired on a population of screened workers (N = 341) from two steel manufacturing plants located in Zhejiang province, and a textile manufacturing plant located in Henan province, China. All the subjects from the two steel manufacturing plants (N=178) were exposed to complex noise while the subjects from textile manufacturing plant (N=163) were exposed to a Gaussian (G) continuous noise. Each subject was given an otologic examination to determine their pure tone hearing threshold levels (HTL); and had their personal 8-hour equivalent A-weighted noise exposure (LAeq) and full shift noise kurtosis statistic (which is sensitive to the peaks and temporal characteristics of noise exposures) measured. For each subject an unadjusted and kurtosis-adjusted cumulative noise exposure (CNE) index for the years worked was created. Multiple linear regression analysis controlling for age was used to determine the relationship between CNE (unadjusted and kurtosis-adjusted) and the mean HTL at 3, 4 and 6 kHz (HTL346) among the complex noise exposed group. In addition, each subjects' HTLs from 0.5 - 8.0 kHz were age and gender adjusted using ANNEX A (ISO-1999) to determine whether they had adjusted high frequency noise induced hearing loss (AHFNIHL), defined as an adjusted HTL shift of 30 dB or greater at 3.0, 4.0 or 6.0 kHz in either ear. Dose-response curves for AHFNIHL were developed separately for workers exposed to G and non-G noise using both unadjusted and adjusted CNE as the exposure matric. Results Multiple linear regression analysis among complex exposed workers demonstrated that the correlation between HTL3,4,6 and CNE controlling for age was improved when using the kurtosis-adjusted CNE compared to the unadjusted CNE (R2=0.386 vs. 0.350), and that noise accounted for a greater proportion of hearing loss. In addition, while dose-response curves for AHFNIHL were distinctly different when using unadjusted CNE, they overlapped when using the kurtosis-adjusted CNE. Conclusions For the same exposure level, the prevalence of NIHL is greater in workers exposed to complex noise environments than for workers exposed to a continuous noise. Kurtosis adjustment of CNE both improved the correlation with NIHL and provides a single metric for dose response effects across different types of noise. The kurtosis-adjusted CNE may be a reasonable candidate for use in NIHL risk assessment across a wide variety of noise environments.

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This pilot study demonstrated that machine learning algorithms are potential tools for the evaluation and prediction of noise-induced hearing impairment in workers exposed to diverse complex industrial noises.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Objectives: To evaluate (1) the accuracy of the International Organization for Standardization (ISO) standard ISO 1999 [(2013), International Organization for Standardization, Geneva, Switzerland] predictions of noise-induced permanent threshold shift (NIPTS) in workers exposed to various types of high-intensity noise levels, and (2) the role of the kurtosis metric in assessing noise-induced hearing loss (NIHL). Design: Audiometric and shift-long noise exposure data were acquired from a population (N = 2,333) of screened workers from 34 industries in China. The entire cohort was exclusively divided into subgroups based on four noise exposure levels (85 ≤ LAeq.8h < 88, 88 ≤ LAeq.8h < 91, 91 ≤ LAeq.8h < 94, and 94 ≤ LAeq.8h ≤ 100 dBA), two exposure durations (D ≤ 10 years and D > 10 years), and four kurtosis categories (Gaussian, low-, medium-, and high-kurtosis). Predicted NIPTS was calculated using the ISO 1999 model for each participant and the actual measured NIPTS was corrected for age and sex also using ISO 1999. The prediction accuracy of the ISO 1999 model was evaluated by comparing the NIPTS predicted by ISO 1999 with the actual NIPTS. The relation between kurtosis and NIPTS was also investigated. Results: Overall, using the average NIPTS value across the four audiometric test frequencies (2, 3, 4, and 6 kHz), the ISO 1999 predictions significantly (p < 0.001) underestimated the NIPTS by 7.5 dB on average in participants exposed to Gaussian noise and by 13.6 dB on average in participants exposed to non-Gaussian noise with high kurtosis. The extent of the underestimation of NIPTS by ISO 1999 increased with an increase in noise kurtosis value. For a fixed range of noise exposure level and duration, the actual measured NIPTS increased as the kurtosis of the noise increased. The noise with kurtosis greater than 75 produced the highest NIPTS. Conclusions: The applicability of the ISO 1999 prediction model to different types of noise exposures needs to be carefully reexamined. A better understanding of the role of the kurtosis metric in NIHL may lead to its incorporation into a new and more accurate model of hearing loss due to noise exposure.

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Objective Data on noise‐induced hearing loss (NIHL) in the automotive industry are rare. This pilot study aimed to investigate the prevalence and determinants of NIHL among workers in the automotive industry in China. Methods A cross‐sectional survey was conducted with 6557 participants from the automotive industry. The questionnaire survey was administered, and individual noise exposure level (LAeq.8h) and hearing loss level were measured. Results Of participants, 96.43% were male; the median age was 27.0 years and 28.82% had NIHL defined as adjusted high‐frequency noise‐induced hearing loss (AHFNIHL). Concerning individual noise levels (LAeq.8h), 62.53% exceeded 85 dB(A), which were mainly concentrated in various jobs, including metal cutting, surface treatment, stamping, welding, grinding, assembly, plastic molding, and forging. Each typical noise source generated its own unique temporal waveform shape with the type of non‐Gaussian noise. Of workers, 53.15% regularly used hearing protector devices (HPD), and the proportion of regular HPD use increased with LAeq.8h. The trend test showed that the prevalence of AHFNIHL in male workers significantly increased with an increase in LAeq.8h at <94 dB(A) and cumulative noise exposure (CNE) in each age group (P < 0.05 or P < 0.01). A logistic regression analysis showed that CNE and HPD usage frequency were important factors contributing to AHFNIHL. Conclusions CNE and HPD usage frequency were the determinants for NIHL. Much more human surveys are needed to understand the prevalence and determinants of NIHL in the automotive industry in China.

Objective: The association of occupational noise-induced hearing loss (NIHL) with noise energy was well documented, but the relationship between occupational noise and noise temporal structure is rarely reported. The objective of this study was to investigate the principal characteristics of the relationship between occupational NIHL and the temporal structure of noise. Methods: Audiometric and shift-long noise exposure data were collected from 3102 Chinese manufacturing workers from six typical industries through a cross-sectional survey. In data analysis, A-weighted 8-h equivalent SPL ( L Aeq.8h ), peak SPL, and cumulative noise exposure (CNE) were used as noise energy indicators, while kurtosis (β) was used as the indicator of noise temporal structure. Two NIHL were defined: (1) high-frequency noise-induced hearing loss (HFNIHL) and (2) noise-induced permanent threshold shift at test frequencies of 3, 4, and 6 kHz (noise-induced permanent threshold shift [NIPTS 346 ]). The noise characteristics of different types of work and the relationship between these characteristics and the prevalence of NIHL were analyzed. Results: The noise waveform shape, with a specific noise kurtosis, was unique to each type of work. Approximately 27.92% of manufacturing workers suffered from HFNIHL, with a mean NIPTS 346 of 24.16 ± 14.13 dB HL. The Spearman correlation analysis showed that the kurtosis value was significantly correlated with the difference of peak SPL minus its L Aeq.8h across different types of work ( p < 0.01). For a kurtosis-adjusted CNE, the linear regression equation between HFNIHL% and CNE for complex noise almost overlapped with Gaussian noise. Binary logistic regression analysis showed that L Aeq.8h , kurtosis, and exposure duration were the key factors influencing HFNIHL% ( p < 0.01). The notching extent in NIPTS at 4 kHz became deeper with the increase in L Aeq.8h and kurtosis. HFNIHL% increased most rapidly during the first 10 years of exposure. HFNIHL% with β ≥ 10 was significantly higher than that with β < 10 ( p < 0.05), and it increased with increasing kurtosis across different CNE or L Aeq.8h levels. When L Aeq.8h was 80 to 85 dB(A), the HFNIHL% at β ≥ 100 was significantly higher than that at 10 ≤ β < 100 or β < 10 ( p < 0.05 and p < 0.01, respectively). Conclusions: In the evaluation of hearing loss caused by complex noise, not only noise energy but also the temporal structure of noise must be considered. Kurtosis of noise is an indirect metric that is sensitive ...

To examine the effects of prolonged visual display terminal (VDT) working hours and exercise frequency on VDT-related symptoms, we recruited 944 Chinese internet staff for the study. A self-administered questionnaire survey was used to obtain the hours of daily VDT work, exercise frequency, and the physical and mental health of the participants. The daily VDT working time of participants was 8.7 hours. Musculoskeletal pain and eye complaints were prevalent, and the participants had poor mental health status. When daily VDT operation time was more than 11 hours, VDT-related symptoms, including backache (odds ratios (OR) = 3.59), wrist pain (OR = 1.88), hip pain (OR = 2.42), dry eyes (OR = 2.22), and ocular soreness (OR = 2.16) were more likely to occur, and an increased risk of serious occupational stress (OR = 6.75) and job burnout (OR = 2.66) was found in internet workers. Compared with those who never exercised, appropriate exercise frequency (three times per week) was helpful to relieve pain in the shoulders (OR = 0.28), neck (OR = 0.45), back (OR = 0.30), lower back (OR = 0.25), and wrists (OR = 0.38), as well as to prevent vision loss (OR = 0.33) and job burnout (OR = 0.42). Therefore, avoiding excessive VDT exposure and performing moderate exercise could protect the physical and mental health of internet staff from the adverse effects of VDT.