A retrospective analysis of noise-induced hearing loss in the Dutch construction industry

The dose-response relationship between noise-induced hearing loss and cumulative noise exposure adjusted by the effect of hearing protection devices among workers in Southern China

The noise exposure levels of workers wearing hearing protective devices (HPDs) depend on ambient noise and the protective effect of hearing protectors. This cross-sectional study aimed to adjust for cumulative noise exposure (CNE) based on the effective protection of hearing protection devices and explore the dose-response relationship between noise-induced hearing loss (NIHL) and adjusted cumulative noise exposure. A questionnaire was used to acquire the basic characteristics and occupational information of noise-exposed workers. Individual noise dosimetry, individual fitting tests, and pure-tone audiometric tests were performed to assess workers' noise exposure levels, HPDs' sound attenuation, and hearing status. A total of 714 workers participated in this study. Four hundred seventy-three participants wore foam earplugs and 241 wore pre-molded earplugs. The median Personal Attenuation Rating (PAR) was 13.0 dB. The median PAR' (the PAR after combining the earplugs usage time) was 8.0 dB. Thirty-one percent of the workers wore earplugs properly during noise exposure and they tended to possess a greater PAR. The median LAeq,8h was 94.1 dB (A) and the median unadjusted cumulative noise exposure was 102.3 dB (A)· year. The PAR'-adjusted CNE (CNEP) was 91.3 dB (A)·year. A total of 161 workers (22.5%) with hearing loss were identified. There was an obvious trend between the prevalence of NIHL and CNEP (χtrend2 = 31.9, p < 0.01). The Wald values of the CNE and CNEP logistic regression models were 4.0 and 14.1, respectively. Furthermore, the curve slope of the CNEP was steeper than that of the unadjusted CNE. The CNEP can represent the noise exposure level among workers wearing hearing protectors more accurately and has an apparent dose-response relationship with the prevalence of NIHL. For workers utilizing hearing protection devices, wearing them properly and consistently in the workplace is recommended. Assessing noise exposure based on the protective effects of hearing protectors is also essential. Additional studies are needed to quantify the impact of behaviors associated with the improper use of hearing protection.

Serum homocysteine is a biomarker for hearing loss associated with or without cardiovascular risk: a cross-sectional study in men

PURPOSE

Hearing loss (HL) represents a major health problem worldwide, and increasingly so due to population ageing and new leisure activities, such as video gaming or virtual reality experiences. HL has a multifactorial origin including both genetic and environmental issues with nutrition status emerging as a new contributing factor. In fact, certain micronutrient deficiencies, along with excessive consumption of specific macronutrients, have been related to HL This study aimed to examine the association of HL with dietary fat intake, nutritional status biomarkers, and serum metabolic signature in aviation pilots and controls.

METHODS

A cohort of aviation pilots, chronically exposed to noise pollution at work, was compared to a cohort of non-exposed university workers (controls). Hearing function was determined by tonal audiometry and dietary fat intake was assessed by three 24-h recalls. In addition, lipoprotein profiles as well as serum homocysteine (Hcy), folate, vitamins B12 and D were analysed. Two multiple linear regression models adjusted for age were constructed to explain HL variability.

RESULTS

HL prevalence was similar and elevated in both cohorts (controls: 64% vs. noise-exposed: 65%), when compared to the American Speech-Language-Hearing Association (ASHA) classification. When comparing both cohorts, although no significant differences were found in Hcy and folate levels, controls had significantly lower vitamins B12 and D concentrations and, conversely, higher serum lipids and lipoprotein values (triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol subfractions), suggesting the possible involvement of CV risk in HL in the control cohort. In the noise-exposed cohort, HL was associated with flight hours, Hcy, and folate (r2 = 0.439), while in controls, HL was associated with Hcy and vitamin D (r2 = 0.474). After adjusting for CV profile, the positive association between HL and Hcy was maintained (β = 0.444; p < 0.001), evidencing the strong involvement of this metabolite not only in CV risk, but also in HL.

CONCLUSION

Folate insufficiency together with hyperhomocysteinemia increased susceptibility to noise-induced HL. However, the role of Hcy in HL without noise exposure at work seems to be partially masked by an altered CV profile.

Application of the occupational health risk assessment model in predicting the risk of noise-induced hearing loss in noise-polluted manufacturers in southern China

Objective. This study aimed to evaluate the correlation between occupational noise-induced hearing loss (ONIHL) and noise exposure in different positions within manufacturing facilities that primarily produce electronic devices, wooden furniture and hardware machinery in southern China and to investigate the practical application of the risk assessment model. Methods. Noise exposure data were collected from 115 workers in 10 manufacturing industries in southern China through on-site investigation. Subsequently, sample testing was conducted in accordance with Chinese standards. The 31 job positions investigated were classified into two similar exposure groups (SEGs). The occupational health risk assessment (OHRA) model was used to evaluate the risks of ONIHL in various job positions. Results. More than half of the positions in both groups had noise levels exceeding 85 dB. In both SEGs, male workers exhibited similar risk patterns of acquiring hearing impairment, with a more pronounced and earlier risk of hearing loss compared to female workers. Age was also found to be a risk factor for hearing impairments. Conclusion. The ORHA model demonstrated a positive correlation between noise exposure levels and NIHL. This model can help employers assess job management with noise exposure and take measures to implement an effective risk management system.

Serum Prestin and Otolin-1 Levels in Pilots of Helicopter-Based Emergency Medical Services: Potential Markers for Ear Injury

INTRODUCTION

Occupational noise exposure is a major public health concern, impacting a large workforce worldwide. In this study, we sought to evaluate the serum concentrations of prestin, a cochlear protein that diminishes following noise exposure, and otolin-1, a protein secreted into the bloodstream subsequent to inner ear damage, among three diverse professional categories, each exposed to varying degrees of noise. Helicopter emergency medical service (HEMS) pilots and construction workers were considered high-risk groups due to their elevated exposure to occupational noise, whereas office workers were regarded as a low-risk group, reflecting their comparatively minimal noise exposure.

METHODS

The study sample included 60 males, encompassing helicopter pilots, construction laborers, and office workers (n=20, each). Recruitment occurred during standard occupational health visits, with all participants presenting normal clinical audiograms. Serum levels of prestin and otolin-1 were measured in duplicate using commercially available immunoassays and compared across the three professional categories.

RESULTS

HEMS pilots had the lowest mean serum prestin level at 211±27 pg/mL, followed by construction workers at 234±29 pg/mL, and office workers at 269±42 pg/mL (p<0.001, one-way analysis of variance), with all inter-group differences statistically significant (p<0.05, Tukey's post hoc tests). For otolin-1, HEMS pilots showed the highest mean at 216±20 pg/mL, with construction workers at 196±22 pg/mL, and office workers at 181±20 pg/mL (p<0.001, one-way analysis of variance). Statistically significant differences were found between HEMS pilots and both other groups for otolin-1 levels (p<0.05, Tukey's post hoc tests), but not between construction workers and office workers.

CONCLUSIONS

 Serum concentrations of prestin and otolin-1 may differ among healthy individuals according to their occupational noise exposure and have the potential to act as indicators of subclinical inner ear injury. To substantiate these preliminary observations, incorporating exposure assessment, especially via direct measurements of noise and vibration exposure, would markedly improve the reliability of our findings.

Noise-induced Hearing Loss: Continuous versus Impact/impulse Noise

Background

Impact/impulse and continuous noise are two main causes of noise-induced hearing loss (NIHL) in workplaces. The aim of this study was to compare the effects of impulse/impact noise and continuous noise on hearing status.

Methods

In this study, 259 workers referred to the occupational medicine clinic of Shahid Rahnemoun hospital, Yazd, Iran, entered the study and were divided into two groups: with exposure to impact/impulse noise and with exposure to continuous noise. Hearing thresholds were measured and compared between the two groups by pure-tone audiometry (PTA). The frequency of hearing loss and audiometric notch according to the results of PTA was compared between the two groups. Data were analyzed by SPSS (ver. 16) using Student's t-test, Chi-square test, and Mann-Whitney U test.

Results

Hearing thresholds were significantly higher at all frequencies in the impact noise group. The hearing threshold at 6000 Hz was higher than other frequencies in both groups. The frequency of hearing loss at high frequencies was higher in the impact group. The frequency of audiometric notch was not significantly different between the two groups.

Conclusions

The results of this study showed that hearing loss after exposure to impact/impulse noise is probably more frequent and more severe than exposure to continuous noise, but the pattern of hearing loss is similar in both types of noise exposure.

Investigation of critical factors influencing the underestimation of hearing loss predicted by the ISO 1999 predicting model

OBJECTIVE

To analyze factors influencing the underestimation of noise-induced permanent threshold shift (NIPTS) among manufacturing workers, providing baseline data for revising noise exposure standard.

DESIGN

A cross-sectional study was designed with 2702 noise-exposed workers from 35 enterprises from 10 industries. Personal noise exposure level(LAeq,8h) and noise kurtosis level were determined by a noise dosimeter. Questionnaires and hearing loss tests were performed for each subject. The predicted NIPTS was calculated using the ISO 1999:2013 model for each participant, and the actual measured NIPTS was corrected for age and sex. The factors influencing the underestimation of NIPTS were investigated.

RESULTS

The predicted NIPTS at each test frequency (0.5, 1, 2, 3, 4, or 6kHz) and mean NIPTS at 2, 3, 4, and 6kHz (NIPTS2346) using the ISO 1999:2013 model were significantly lower than their corresponding measured NIPTS, respectively (P < 0.001). The ISO model significantly underestimated the NIPTS2346 by 12.36 dB HL. The multiple linear regression analysis showed that noise exposure level, exposure duration, age, and kurtosis could affect the degree of underestimation of NIPTS2346. The generalized additive model (GAM) with (penalized) spline components showed nonlinear relationships between critical factors (age, exposure duration, noise level, and kurtosis) and the underestimated NIPTS2346.The underestimated NIPTS2346 decreased with an increase in exposure duration (especially over ten years). There was no apparent trend in the underestimated NIPTS2346 with age. The underestimated NIPTS2346 decreased with the increased noise level [especially > 90 dB(A)]. The underestimated NIPTS2346 increased with an increase in noise kurtosis after adjusting for the noise exposure level and exposure duration and ultimately exhibiting a linear regression relationship.

CONCLUSIONS

The ISO 1999 predicting model significantly underestimated the noise-induced hearing loss among manufacturing workers. The degree of underestimation became more significant at the noise exposure condition of fewer than ten years, less than 90 dB(A), and higher kurtosis levels. It is necessary to apply kurtosis to adjust the underestimation of hearing loss and consider the applying condition of noise energy metrics when using the ISO predicting model.

Leisure noise exposure and hearing outcomes among Canadians aged 6 to 79 years

OBJECTIVE

To examine the association between individual and cumulative leisure noise exposure in addition to acceptable yearly exposure (AYE) and hearing outcomes among a nationally representative sample of Canadians.

DESIGN

Audiometry, distortion-product otoacoustic emissions (DPOAEs) and in-person questionnaires were used to evaluate hearing and leisure noise exposure across age, sex, and household income/education level. High-risk cumulative leisure noise exposure was defined as 85 dBA or greater for 40 h or more per week, with AYE calculations also based on this occupational limit.

STUDY SAMPLE

A randomised sample of 10,460 respondents, aged 6-79, completed questionnaires and hearing evaluations between 2012 and 2015.

RESULTS

Among 50-79 year olds, high-risk cumulative leisure noise was associated with increased odds of a notch while high exposure to farming/construction equipment noise was associated with hearing loss, notches and absent DPOAEs. No associations with hearing loss were found however, non-significant tendencies observed included higher mean hearing thresholds, notches and hearing loss odds.

CONCLUSION

Educational outreach and monitoring of hearing among young and middle-aged populations exposed to hazardous leisure noise would be beneficial.

Noise exposure assessment of non-coal mining workers in four provinces of China

Objective

This study aimed to understand the noise exposure of non-coal mines in China to take appropriate controls to protect workers' health.

Methods

An assessment of non-coal miners' noise exposures was conducted in four provinces in China. Individual noise exposure levels were measured, and the survey on the hearing protector device (HPD) equipment was administered.

Results

423 noise dosimeter measurements were obtained, including drilling, blasting, ore drawing, transportation, winching, crushing, screening and ball milling, and auxiliary (air pressure, pump, and maintenance). A total of 31.9% of the individual noise levels (L_EX,8h) exceeded 85 dB(A), and the median dosages of non-coal miners with high noise exposure were: excavation workers-89.1 dB(A), mill operators-88.7 dB(A), and crusher operators-87.0 dB(A). The noise dose of underground mine workers is higher than that of surface mine workers (P < 0.001). A total of 53.7% of non-coal mining enterprises are not equipped with HPD for workers, mainly small and micro enterprises.

Conclusions

High levels of hazardous noise exposure are typical in non-coal mines. Noise exposure data can help to develop more feasible noise controls.

Occupation and 20-year hearing decline: findings from The HUNT Study

BACKGROUND

Studies show that certain occupations are associated with an increased risk of hearing loss. However, many studies are cross-sectional, and the few longitudinal studies are mostly small or focus on only one occupation.

AIMS

We aimed to quantify the long-term hearing decline among workers in different occupations and assess whether the change differs between the occupations.

METHODS

The study population was 4525 adults who participated in two population-based health studies in Norway, HUNT2 1996-1998 and HUNT4 2017-2019. Linear regression models assessed the association between occupations (clerks as reference) and 20-year hearing decline (hearing thresholds at 3-6 kHz, averaged over both ears) from HUNT2 to HUNT4. Models were adjusted for age, sex, recurrent ear infections, smoking and ear pathology.

RESULTS

Among the participants (40% men), the mean age at HUNT2 was 31.2 ± 5.4 years (range 20-39) and the average 20-year hearing decline was 11.3 ± 9.8 dB. Occupations that were associated with larger hearing decline included other craft and related trades workers (3.9 dB, 95% confidence interval [CI] 0.2-7.7) and building frame and related trades workers (3.4 dB, 95% CI 1.3-5.4). Among occupations with larger hearing decline, a higher proportion of the workers reported exposure to noise.

CONCLUSIONS

This large longitudinal study shows a larger long-term hearing decline among building frame workers and craft and related trades workers. Differences between occupations were modest, which may indicate successful preventive measures in Norway during the last two decades.

Hearing Function and Nutritional Status in Aviation Pilots from Spain Exposed to High Acoustic Damage

Noise-induced hearing loss is the most frequent and preventable occupational disease. Aviation pilots are a vulnerable population, as they spend many hours exposed to noise pollution in their working environment. Different studies suggest that certain dietary compounds may play a key role in the etiology and prevention of this pathology. We aimed to study the relationship linking auditory function, dietary intake, and some serum biomarkers in pilots, exposed to noise in the work environment. A total of 235 pilots, who undergo a periodic medical examination at the Centro de Instrucción de Medicina Aeroespacial (Madrid, SPAIN), were evaluated. Auditory function was assessed by tonal audiometry. Energy and nutrient intakes were estimated by 24 h recall (DIALTM program). Serum homocysteine (Hcy) was determined in a Cobas 6000TM multi-analyzer while folate, vitamin B12, and D were analyzed in a Cobas e411TM. The prevalence of hearing loss (HL) was 64.3%. HL was significantly related to age (r = 0.588, p ≤ 0.001) and flight hours (r = 0.283, p ≤ 0.001). A multiple linear regression model was used to assess the relationship among HL, flight hours, serum folate, and Hcy serum levels. HL was significantly (p < 0.050) associated with flight hours (β = 0.246), serum folate (β = −0.143), and serum Hcy (β = 0.227). Nutritional interventions would be of great interest to monitor and slow down the HL progression in populations exposed to noise pollution in their workplace.

Awareness and usage of personal protective equipment among construction workers and their hearing assessment by pure tone audiometry; A cross-sectional study in South India

CONTEXT

Occupational hazards at the building construction workplace are enormous. Good compliance to the use of personal protective equipment (PPE) alongside other safety measures is critical in reducing the hazards. Occupational hearing loss is one such occupational hazard among construction workers.

AIMS

This study was conducted for determining the awareness of the benefits of PPE and its usage among construction workers along with hearing assessment.

SETTINGS AND DESIGN

A cross-sectional study was conducted among construction workers in a building project in Mangaluru city in Dakshina Kannada district in South India.

METHODS AND MATERIAL

After obtaining informed written consent, 110 construction workers were recruited by simple random sampling method. Basic information, awareness, and use of PPE were collected using a semistructured questionnaire through personal interviews. Hearing assessment was done by pure tone audiometry.

STATISTICAL ANALYSIS USED

Data collected was analyzed. Chi-square test and Fischer's exact probability test were used to test the association between variables.

RESULTS

Majority (85.5%) of the construction workers are working for duration of 15 years or less. Difficulty in hearing was reported by 9.6% of them. Awareness regarding benefits of using personal protective devices like helmets, masks, and earplugs/muffs were 58.2%, 56.4%, and 14.5%, respectively. The utilization of at least one PPE among them was 58.1%. The presence of sensory neural hearing loss (SNHL) in both/either ears was detected among 14.5% of the workers. There was a statistically significant association of SNHL among workers and their duration of construction work.

CONCLUSION

The current study highlights that awareness and usage of PPE was low and a proportion of them had a hearing impairment. Occupational health and safety training along with a periodic examination of construction workers need to be focused so as to detect and manage occupational health hazards early.

The effects of dyslipidemia on noise-induced hearing loss in a petrochemical workers in the Southwest of Iran

BACKGROUND

Research has shown that the decrease in the inner diameter of vessels caused by hyperlipidemia lowers the capacity for blood oxygen delivery to the cochlea. This leads to impaired cochlear metabolism and causes hearing problems.

OBJECTIVE

The effects of dyslipidemia on noise-induced hearing loss in workers were examined.

METHODS

This descriptive cross-sectional study was performed on 692 male employees in a petrochemical industry in the southwest of Iran exposed to 85 dB noise. Clinical audiometry and blood sample tests were used to evaluate the hearing and prevalence indices of dyslipidemia (cholesterol, triglyceride, HDL and LDL). The data were analyzed using SPSS software version 25 (p = 0.05).

RESULTS

The results showed that the prevalence of dyslipidemia was 24.5%with abnormal relative triglyceride frequency of 49.5%, HDL of 28%, LDL of 33%, and total blood cholesterol level of 37.8%. There was no significant relationship between NIHL and dyslipidemia (p >  0.09). However, the major NIHL drops at different frequencies were in the individuals with dyslipidemia. The parameters age and dyslipidemia increased NIHL odds ratio (95%C.I.). by 1.130 (1.160-1.100) and 1.618 (2.418-1.082) respectivelyCONCLUSION:The rate of hearing loss in individuals with dyslipidemia increases at different frequencies and it leads to an increase of the OR of NIHL in individuals with dyslipidemia. We can control dyslipidemia and its effective factors. The NIHL is more common in people exposed to noise.

An assessment of noise exposure and hearing health status among auto body workers in Kermanshah, Iran

BACKGROUND

Unwanted sound is recognized as the most extensive source of contaminant in the workplace. Exposure to intense, continuous, and higher than 85 dB level noise can lead to noise-induced hearing loss. The aim of the present study was to determine the level of noise exposure and its impact on hearing health among auto body workers.

MATERIALS AND METHODS

This descriptive-analytic study was conducted in 2020 to investigate the hearing health status of workers in auto body workshops. Sixty-one participants were randomly selected for audiometric testing. The equivalent sound level (Leq) of the workers was measured using a Casella CEL-320 noise dosimeter. Audiometric testing was performed using an AC40 audiometer. The mean hearing threshold levels (HTLs) of both ears were calculated for different frequencies. The results obtained were analyzed using SPSS v21.0 at a significance level of 95%.

RESULTS

The participants had an average age of 35.5 ± 11.8 years and an average work experience of 16.5 ± 9.8 years. The mean Leq was 92.3 ± 4.7 dB. The mean HTLs for the right ear and left ear were 20, 15, 17.6, 19.2 dB, respectively with the right ear suffering more loss. A significant relationship was found between hearing loss in both ears (P < 0.001). The highest prevalence of hearing loss in both ears was observed at a frequency of 4 kHz. About 73.8% of the subjects had a normal HTL, 23.3% had mild hearing loss, and 3.3% had severe hearing loss. With increasing work experience, HTLs also increased significantly, particularly at 2-8 kHz.

CONCLUSIONS

Chronic exposure to noise pollution threatens hearing health. Therefore, it is necessary to raise the level of awareness among workers in order to enable better hearing health protection and also to promote the use of hearing protection devices.

Physical and Psychoacoustic Characteristics of Typical Noise on Construction Site: "How Does Noise Impact Construction Workers' Experience?"

Construction noise is an integral part of urban social noise. Construction workers are more directly and significantly affected by construction noise. Therefore, the construction noise situation within construction sites, the acoustic environment experience of construction workers, and the impact of noise on them are highly worthy of attention. This research conducted a 7-month noise level (LAeq) measurement on a construction site of a reinforced concrete structure high-rise residential building in northern China. The noise conditions within the site in different spatial areas and temporal stages was analyzed. Binaural recording of 10 typical construction noises, including earthwork machinery, concrete machinery, and hand-held machinery, were performed. The physical acoustics and psychoacoustic characteristics were analyzed with the aid of a sound quality analysis software. A total of 133 construction workers performing 12 types of tasks were asked about their subjective evaluation of the typical noises and given a survey on their noise experience on the construction site. This was done to explore the acoustic environment on the construction site, the environmental experience of construction workers, the impact of noise on hearing and on-site communications, and the corresponding influencing factors. This research showed that the noise situation on construction sites is not optimistic, and the construction workers have been affected to varying degrees in terms of psychological experience, hearing ability, and on-site communications. Partial correlation analysis showed that the construction workers' perception of noise, their hearing, and their on-site communications were affected by the noise environment, which were correlated to varying degrees with the individual's post-specific noise, demand for on-site communications, and age, respectively. Correlation analysis and cluster analysis both showed that the annoyance caused by typical construction noise was correlated to its physical and psychoacoustic characteristics. To maintain the physical and mental health of construction workers, there is a need to improve on the fronts of site management, noise reduction, equipment and facility optimization, and occupational protection.

Occupational Noise-Induced Hearing Loss among Migrant Workers in Kuwait

Although the effect of hearing loss on years lived with disability (YLD) is quite substantial, occupational hearing loss among migrant workers is significantly under-studied. In Kuwait, where nearly two-thirds of the population are migrant workers, the burden of occupational noise-induced hearing loss (ONIHL) is unknown. The objective of the study was to assess the prevalence of ONIHL among migrant workers in Kuwait and explore workplace and individual risk factors that are associated with ONIHL. We obtained data of annual physical exams for the year 2018 conducted by the Shuaiba Industrial Medical Center (SIMC) for all industrial workers in the area. We applied univariate and multivariate logistic regression models to estimate the effects of individual and occupational characteristics on ONIHL. A total of 3474 industrial workers visited the SIMC for an annual exam. The vast majority were men (99%) and non-Kuwaitis (98%) with a median age of 38 years. A total of 710 workers were diagnosed with ONIHL with a prevalence of 20.4%. Age, years of experience, and self-reported exposure to noise were associated with statistically significant higher odds of ONIHL. When adjusted for age, years of experience, and other individual level factors, type of industry was not a statistically significant predictor of ONIHL. The study uncovers the significant burden of hearing loss among the migrant worker subpopulation in Kuwait, an area of occupational health that is often underestimated or unrecognized. Although laws and regulations are in place to prevent and control noise in the workplace, the onus is on local authorities to ensure the necessary training and controls aimed to reduce noise exposure.

Loud Music and Leisure Noise Is a Common Cause of Chronic Hearing Loss, Tinnitus and Hyperacusis

High sound levels capable of permanently damaging the ear are experienced not only in factories and war zones but in concert halls, nightclubs, sports stadiums, and many other leisure environments. This review summarizes evidence that loud music and other forms of "leisure noise" are common causes of noise-induced hearing loss, tinnitus, and hyperacusis, even if audiometric thresholds initially remain within clinically normal limits. Given the huge global burden of preventable noise-induced hearing loss, noise limits should be adopted in a much broader range of settings, and education to promote hearing conservation should be a higher public health priority.

An overview of occupational noise-induced hearing loss among workers: epidemiology, pathogenesis, and preventive measures

Occupational noise-induced hearing loss (ONIHL) is the most prevalent occupational disease in the world. The goal of this study was to review the epidemiology, pathogenesis, and preventive measures of ONIHL among workers and provide evidence for the implementation of control measures. Literature studies were identified from the MEDLINE, PubMed, Embase, Web of Science, and Google Scholar using the search terms “noise-induced hearing loss” “prevalence”, “pathogenesis”, and “preventive measures”. The articles reviewed in this report were limited from 2000 to 2020. Articles that were not published in the English language, manuscripts without an abstract, and opinion articles were excluded. After a preliminary screening, all of the articles were reviewed and synthesized to provide an overview of the current status of ONIHL among workers. The mechanism of ONIHL among workers is a complex interaction between environmental and host factors (both genetic and acquired factors). The outcomes of noise exposure are different among individual subjects. Clinical trials are currently underway to evaluate the treatment effect of antioxidants on ONIHL. Noise exposure may contribute to temporary or permanent threshold shifts; however, even temporary threshold shifts may predispose an individual to eventual permanent hearing loss. Noise prevention programs are an important preventive measure in reducing the morbidity of ONIHL among workers.

Noise Exposure and Hearing Loss among Brewery Workers in Lagos, Nigeria

The health risks of exposure to loud noises are a well-established fact and are widely addressed in modern industries. Yet, in less developed countries, it is thought these hazards receive less attention, both in the workplace and in private life. (1) Background: The aim of this study is to assess the occupational noise exposure in a developing country and identify possible risk groups for whom intervention is needed. (2) Methods: A cross-sectional study was performed among brewery employees in Lagos, Nigeria. Pure-tone audiometry (PTA) was performed, paired with a self-report questionnaire. Personal noise dosimetry (PND) was also performed with an additional group of participants. (3) Results: A total of 458 employees were submitted to PTA. The Packaging and Utilities department reported the largest shifts in hearing thresholds (18 dB [sd = 15] and 16 dB [sd = 15] @4kHz, respectively). No significant effect of department type on auditory health could be found. PND results were obtained from 39 employees. Packaging and Sales were identified as the most exposed departments. (4) Conclusions: A healthy hearing profile was found for a large proportion of the brewery employees (91.7%). However, NIHL (noise-induced hearing loss) proportions specifically among Bottling and Sales employees were elevated.

Early hearing slope as a predictor of subsequent hearing trajectory in a noise-exposed occupational cohort

Variations in individual susceptibility to noise-induced hearing loss have been observed among workers exposed to similar ambient noise levels but the reasons for this observation are poorly understood. Many workers are exposed to hazardous levels of occupational noise throughout their entire careers. Therefore, a mechanism to identify workers at risk for accelerated hearing loss early in their career may offer a time-sensitive window for targeted intervention. Using available longitudinal data for an occupationally noise-exposed cohort of manufacturing workers, this study aims to examine whether change in an individual's high frequency hearing level during the initial years of occupational noise exposure can predict subsequent high frequency hearing loss. General linear mixed modeling was used to model later hearing slope in the worse ear for the combined frequencies of 3, 4, and 6 kHz as a function of early hearing slope in the worse ear, age at baseline, sex, race/ethnicity, mean ambient workplace noise exposure, and self-reported non-occupational noise exposure. Those with accelerated early hearing loss were more likely to experience a greater rate of subsequent hearing loss, thus offering a potentially important opportunity for meaningful intervention among those at greatest risk of future hearing loss.

Noise-induced hearing loss and its prevention: Integration of data from animal models and human clinical trials

Animal models have been used to gain insight into the risk of noise-induced hearing loss (NIHL) and its potential prevention using investigational new drug agents. A number of compounds have yielded benefit in pre-clinical (animal) models. However, the acute traumatic injury models commonly used in pre-clinical testing are fundamentally different from the chronic and repeated exposures experienced by many human populations. Diverse populations that are potentially at risk and could be considered for enrollment in clinical studies include service members, workers exposed to occupational noise, musicians and other performing artists, and children and young adults exposed to non-occupational (including recreational) noise. Both animal models and clinical populations were discussed in this special issue, followed by discussion of individual variation in vulnerability to NIHL. In this final contribution, study design considerations for NIHL otoprotection in pre-clinical and clinical testing are integrated and broadly discussed with evidence-based guidance offered where possible, drawing on the contributions to this special issue as well as other existing literature. The overarching goals of this final paper are to (1) review and summarize key information across contributions and (2) synthesize information to facilitate successful translation of otoprotective drugs from animal models into human application.

Prevalence of loud leisure noise activities among a representative sample of Canadians aged 6-79 years

This population-based study estimates the prevalence of loud leisure noise exposure and hearing protection usage among Canadians, as well as the population potentially at-risk using an occupational limit of 85 dBA, LEX 40 h, which denotes a typical occupational noise limit for a 40 hour work week. A total of 10 460 participants, aged 6-79 years, completed a Canadian Health Measures Survey household questionnaire. Loud leisure noise was defined by vocal effort required while communicating at arm's length except for loud personal listening device (PLD) usage with earbuds/headphones, which included both volume setting and vocal effort. The most prevalent loud leisure noise activities were amplified music, car/home stereo listening, and power tools, with 40% reporting each source, followed by sporting/entertainment (25%), gasoline engines (23%), and loud PLD listening (19.5%). Loud leisure noise was more prevalent among 12-39 year olds and males. Hearing protection usage was uncommon, from 44.2% (firearms) to 20.3% (power tools) and below 3% during amplified music and sporting/entertainment events. Calculations using self-reported duration of loud leisure noise activities estimated that 6.6 × 10⁶ Canadians were in the high cumulative noise exposure category. A large proportion of Canadians would be expected to develop some degree of noise-induced hearing loss should this pattern persist over years.

Severe Temporal Hyper-Activated States Caused by Noise in Tinnitus and Hyperacusis with Normal Hearing

Lots of neuroimaging and animal studies have revealed that tinnitus and hyperacusis share the same patterns in the bottom up central auditory process. The aim was to identify the abnormal central patterns commonly observed in both tinnitus and hyperacusis in humans. We investigated two cases of normal hearing: a tinnitus patient and a hyperacusis patient. We compared the differences between the severe temporal hyper-activated state (STHS), with spikes, fast beta and gamma frequencies after noise exposure, and the mild temporal hyper-activated state (MTHS), in no sound exposed condition. The power of the gamma band in the two cases was increased in both auditory cortices compared to the other brain regions. Our results of human with normal hearing were the first to identify how tinnitus and hyperacusis caused by sound are abnormally active and how they maintain constant pathological states.

Prevalence and determinants of noise-induced hearing loss among workers in the automotive industry in China: A pilot study

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 (L_Aeq.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 (L_Aeq.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 L_Aeq.8h. The trend test showed that the prevalence of AHFNIHL in male workers significantly increased with an increase in L_Aeq.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.

A Cross-Sectional Study on the Hearing Threshold Levels Among People in Qinling, Qinghai, and Nanjing, China

PURPOSE

This study aimed to investigate the hearing threshold among different age groups, genders, and geographic areas in China to provide some insight into the appropriate clinical interventions for hearing loss.

METHOD

Using a systematic random sampling technique, 562 participants from Qinling, Qinghai, and Nanjing were included. Participants in the same area were divided into 3 groups according to their age. Pure-tone audiometric thresholds were measured at octave and interoctave frequencies of 0.125-16 kHz for each subject.

RESULTS

There were significant differences in auditory thresholds at nearly all frequencies among young, middle-aged, and elderly people, and hearing thresholds increased with increasing age. People generally had the best hearing ability in Nanjing, better hearing ability in Qinghai, and the worst hearing ability in Qinling. Significant differences in hearing thresholds were found between males and females at several frequencies in Qinling.

CONCLUSION

People living in the rural area of Qinling in China had higher hearing threshold levels, particularly males, and hearing thresholds increased with age.

Psychosocial hearing disadvantage and associated factors among construction workers in Mato Grosso, Brazil

OBJECTIVE

To estimate the prevalence and to analyze the factors associated with self-reported hearing handicap by construction workers in the state of Mato Grosso, Brazil.

METHODS

A cross-sectional study was conducted with 866 construction and heavy construction workers. Participants responded to an epidemiological survey subdivided in: identification data, sociodemographic data; lifestyle; work environment characteristics; occupational exposure factors; hearing protection measures; and hearing handicap inventory to quantify the psychosocial consequences of work-related hearing loss.

RESULTS

The prevalence of hearing impairment among workers in the construction sector was 14.43% (n = 125). There were 311 emotional and social complaints related to hearing problems. Hearing handicap was associated with: 60 or over age group (PR = 1.94, 95%CI 1.01 - 3.71); alcohol consumption (PR = 1.94, 95%CI 1.38 - 2.73); direct exposure to noise (PR = 1.75; 95%CI 1.03 - 2.97); exposure to dust (PR = 1.59, 95%CI 1.13 - 2.24); non-use of earplugs (PR = 1.39, 95%CI 1.00 - 1.93); and non-use of neck flap cap (PR = 1.52, 95%CI 1.09 - 2.13).

CONCLUSION

We observed a high prevalence of hearing impairment among workers in the construction sector associated with: individuals aged 60 years or older; alcoholism; exposure to noise and dust; non-use of earplugs; and non-use of neck flap cap. Therefore, it is necessary to implement policies aimed at preserving the hearing health of construction and heavy construction workers.

Effects of long-term construction noise on health of adult female Wistar rats

The aim of this study was to investigate the influence of long-term building construction noise from refurbishment, which including vibration, on some physiological parameters and histopathological changes of organs of Wistar rats. Twenty 12 month old female rats were divided into two groups: rats group I (n = 10) were exposed to long-term construction noise and rats group II (n = 10) were kept under normal noise level. Study results revealed that long-term construction noise from building refurbishment has an influence on body weight, haematological and some serum biochemical parameters affects caecal microbiota, and causes histopathological changes in the organs of adult female Wistar rats. It was noticed that rats in group I exihibited significantly higher mean values for total protein, albumin and lower values for glucose, AST, ALT, blood urea nitrogen, haematological and caecal microbiota parameters than rats in group II. The most common pathologies were determined in the kidney, liver and lungs. Other observed pathologies were lymphadenopathy, catarrhal inflammation of the intestines, spleen hyperplasia and mammary gland adenofibroma. Single cases were subcutaneous fibroma in the thoracic region, abortus with uterine inflammation and thymus hyperplasia with formation of cysts were found.

The Use of Noise Dampening Mats to Reduce Heavy-Equipment Noise Exposures in Construction

The performance of sound barriers was evaluated to determine their technical effectiveness and practicality in reducing noise exposures to operating engineers in construction. Commercially purchased sound dampening mats (SDMats) were installed inside three heavy-equipment engine compartments. Sound pressure levels (SPLs) were measured before and after installing the SDMats while the equipment was on idle and full-throttle settings where it normally operates. SPLs inside the heavy-equipment operator cabs were significantly reduced by 5.6-7.6 dBA on the full-throttle setting following installation of the SDMats (p < 0.01). The evaluated engineering control intervention was simple to install, affordable, and substantially reduced the engine noise reaching the heavy-equipment operator, potentially reducing reliance on hearing-protection devices to protect construction workers from noise exposures.

Civil construction work: The unseen contributor to the occupational and global disease burden

Background:

Construction industry is the second largest employment giving industry in India with many semi-skilled or unskilled workers taking up the occupation for livelihood without any training and proper guidance.

Aim:

To evaluate the pathogenic association of cement exposure to occupational contact dermatoses as evidenced by immune markers and to correlate their pulmonary functions with years of exposure to cement.

Setting and Design:

This was a cross-sectional study conducted among randomly selected cement workers. Methods and material: Evaluation of socioeconomic status (SES) and years of exposure of cement workers was done using a questionnaire. Clinical examination of skin lesions and strip patch test with application of potassium dichromate on unexposed skin was performed. Results were interpreted after 48 hours. Absolute eosinophil count (AEC) and IgE levels measured, and spirometric evaluation was performed.

Statistical Analysis:

Analysis of variance and Pearson's correlation test were used for data analysis. P < 0.05 was considered to be statistically significant.

Results:

Clinically, skin lesions were noticed in 51%, elevated AEC in 47%, and raised Anti IgE in 73%. Two participants developed positive reactions to the skin strip patch test. Duration of exposure to cement and SES were compared with clinical skin lesions. Spirometry result was normal in 81%, obstruction in 8%, restriction in 10%, and mixed pattern in 1%. Forced expiratory volume at 1.0 second, forced expiratory flow (25–75%), and  (PEFR) Peak Expiratory Flow Rate were markedly reduced with years of exposure. Workers who had greater skin lesions and with increase in exposure had increased AEC and IgE levels, although statistically not significant.

Conclusions:

Exposure to cement and poor SES is strongly correlated to increased prevalence of skin lesions and reduced pulmonary functions.

Prevalence of Hazardous Occupational Noise Exposure, Hearing Loss, and Hearing Protection Usage Among a Representative Sample of Working Canadians

OBJECTIVE

The aim of this study was to estimate the prevalence of hearing loss (HL), self-reported occupational noise exposure, and hearing protection usage among Canadians.

METHODS

In-person household interviews were conducted with 3666 participants, aged 16 to 79 years (1811 males) with 94% completing audiometry and distortion-product otoacoustic emission (DPOAE) evaluations. Occupational noise exposure was defined as hazardous when communicating with coworkers at an arm's length distance required speaking in a raised voice.

RESULTS

An estimated 42% of respondents reported hazardous occupational noise exposure; 10 years or more was associated with HL regardless of age, sex or education. Absent DPOAEs, tinnitus, and the Wilson audiometric notch were significantly more prevalent in hazardous workplace noise-exposed workers than in nonexposed. When mandatory, 80% reported wearing hearing protection.

CONCLUSIONS

These findings are consistent with other industrialized countries, underscoring the need for ongoing awareness of noise-induced occupational HL.

Predictive factors of occupational noise-induced hearing loss in Spanish workers: A prospective study

The purpose of our study was to identify the main factors associated with objective noise-induced hearing loss (NIHL), as indicated by abnormal audiometric testing, in Spanish workers exposed to occupational noise in the construction industry. We carried out a prospective study in Tenerife, Spain, using 150 employees exposed to occupational noise and 150 age-matched controls who were not working in noisy environments. The variables analyzed included sociodemographic data, noise-related factors, types of hearing protection, self-report hearing loss, and auditory-related symptoms (e.g., tinnitus, vertigo). Workers with pathological audiograms had significantly longer noise-exposure duration (16.2 ± 11.4 years) relative to those with normal audiograms (10.2 ± 7.0 years; t = 3.99, P < 0.001). The vast majority of those who never used hearing protection measures had audiometric abnormalities (94.1%). Additionally, workers using at least one of the protection devices (earplugs or earmuffs) had significantly more audiometric abnormalities than those using both protection measures simultaneously (Chi square = 16.07; P < 0.001). The logistic regression analysis indicates that the use of hearing protection measures [odds ratio (OR) = 12.30, confidence interval (CI) = 4.36-13.81, P < 0.001], and noise-exposure duration (OR = 1.35, CI = 1.08-1.99, P = 0.040) are significant predictors of NIHL. This regression model correctly predicted 78.2% of individuals with pathological audiograms. The combined use of hearing protection measures, in particular earplugs and earmuffs, associates with a lower rate of audiometric abnormalities in subjects with high occupational noise exposure. The use of hearing protection measures at work and noise-exposure duration are best predictive factors of NIHL. Auditory-related symptoms and self-report hearing loss do not represent good indicators of objective NIHL. Routine monitoring of noise levels and hearing status are of great importance as part of effective hearing conservation programs.

Prevalence of hearing problems and associated factors in an agricultural company in southern Brazil

OBJECTIVE

To describe the prevalence and to analyze the factors associated with hearing problems in an agricultural company.

METHODS

This was a cross-sectional study, and the participants consisted entirely of employees of an agricultural company in southern Brazil. The workforce of the company was composed of several different occupations. The research instrument was a semi-structured questionnaire administered by interview.

RESULTS

Of the 326 workers of the company, there were 273 (83.8%) respondents, and the prevalence of hearing problems was n = 42 (15.4%) among the participants of the study. The hearing problems were associated with lower schooling, with the operating occupational group, the technical assistance group and the general services group. The self-reported health conditions associated with hearing problems were depression and nervousness or irritation. The occupational exposures associated with hearing problems were noise, dust, vibration, oils and solvents, and toxic gases.

CONCLUSION

There was an intermediate prevalence of hearing problems in relation to other studies. It was possible to observe the need to implement strategies aiming at the prevention of hearing problems that primarily contemplate modifiable aspects, such as the use of personal protective equipment, as well as improvements in the conditions, organization and work environment.

Occupational noise exposure and hearing: a systematic review

Purpose

To give a systematic review of the development of noise-induced hearing loss (NIHL) in working life.

Methods

A literature search in MEDLINE, Embase, Web of Science, Scopus, and Health and Safety Abstracts, with appropriate keywords on noise in the workplace and health, revealed 22,413 articles which were screened by six researchers. A total of 698 articles were reviewed in full text and scored with a checklist, and 187 articles were found to be relevant and of sufficient quality for further analysis.

Results

Occupational noise exposure causes between 7 and 21 % of the hearing loss among workers, lowest in the industrialized countries, where the incidence is going down, and highest in the developing countries. It is difficult to distinguish between NIHL and age-related hearing loss at an individual level. Most of the hearing loss is age related. Men lose hearing more than women do. Heredity also plays a part. Socioeconomic position, ethnicity and other factors, such as smoking, high blood pressure, diabetes, vibration and chemical substances, may also affect hearing. The use of firearms may be harmful to hearing, whereas most other sources of leisure-time noise seem to be less important. Impulse noise seems to be more deleterious to hearing than continuous noise. Occupational groups at high risk of NIHL are the military, construction workers, agriculture and others with high noise exposure.

Conclusion

The prevalence of NIHL is declining in most industrialized countries, probably due to preventive measures. Hearing loss is mainly related to increasing age.

Electronic supplementary material

The online version of this article (doi:10.1007/s00420-015-1083-5) contains supplementary material, which is available to authorized users.

ICBEN review of research on the biological effects of noise 2011-2014

The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health.

Prediction of hearing loss among the noise-exposed workers in a steel factory using artificial intelligence approach

PURPOSE

Prediction of hearing loss in noisy workplaces is considered to be an important aspect of hearing conservation program. Artificial intelligence, as a new approach, can be used to predict the complex phenomenon such as hearing loss. Using artificial neural networks, this study aims to present an empirical model for the prediction of the hearing loss threshold among noise-exposed workers.

METHODS

Two hundred and ten workers employed in a steel factory were chosen, and their occupational exposure histories were collected. To determine the hearing loss threshold, the audiometric test was carried out using a calibrated audiometer. The personal noise exposure was also measured using a noise dosimeter in the workstations of workers. Finally, data obtained five variables, which can influence the hearing loss, were used for the development of the prediction model. Multilayer feed-forward neural networks with different structures were developed using MATLAB software. Neural network structures had one hidden layer with the number of neurons being approximately between 5 and 15 neurons.

RESULTS

The best developed neural networks with one hidden layer and ten neurons could accurately predict the hearing loss threshold with RMSE = 2.6 dB and R(2) = 0.89. The results also confirmed that neural networks could provide more accurate predictions than multiple regressions.

CONCLUSIONS

Since occupational hearing loss is frequently non-curable, results of accurate prediction can be used by occupational health experts to modify and improve noise exposure conditions.

Longitudinal changes in hearing threshold levels of noise-exposed construction workers

PURPOSE

Longitudinal analysis of audiometric data of a large population of noise-exposed workers provides insight into the development of noise-induced hearing loss (NIHL) as a function of noise exposure and age, particularly during the first decade of noise exposure.

METHODS

Data of pure-tone audiometry of 17,930 construction workers who underwent periodic occupational hearing screening at least twice during a 4-year period were available for analysis. These concerned all follow-up measurements of the baseline cohort described by Leensen et al. (Int Arch Occup Environ Health 84:577-590, 2011). Linear mixed models explored the relationship between the annual rate of change in hearing and noise exposure level, exposure duration, and age. Data of 3,111 workers who were tested on three occasions were used to investigate the pattern of hearing loss development.

RESULTS

The mean annual deterioration in hearing in this study population was 0.54 dB/yr, and this became larger with increasing noise exposure level and increasing age. Remarkably, during the first decade of noise exposure, an improvement in hearing threshold levels (HTLs) was observed. The change in hearing over three measurements showed a concave development of hearing loss as a function of time, which corresponds to NIHL development.

CONCLUSIONS

Overall, hearing deteriorated over the measurement period. Because HTLs at follow-up were better than those obtained at baseline, no statement can be made about the NIHL development during the first decade of noise exposure. This improvement in HTLs rather resembles the result of measurement variation in occupational screening audiometry than an actual improvement in hearing ability.

Effect of workplace noise on hearing ability in tile and ceramic industry workers in Iran: a 2-year follow-up study

INTRODUCTION

Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers.

METHODS

This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear.

RESULTS

Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively.

CONCLUSIONS

This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices.

Improving occupational health care for construction workers: a process evaluation

Background

To evaluate the process of a job-specific workers’ health surveillance (WHS) in improving occupational health care for construction workers.

Methods

From January to July 2012 were 899 bricklayers and supervisors invited for the job-specific WHS at three locations of one occupational health service throughout the Netherlands. The intervention aimed at detecting signs of work-related health problems, reduced work capacity and/or reduced work functioning. Measurements were obtained using a recruitment record and questionnaires at baseline and follow-up. The process evaluation included the following: reach (attendance rate), intervention dose delivered (provision of written recommendations and follow-up appointments), intervention dose received (intention to follow-up on advice directly after WHS and remembrance of advice three months later), and fidelity (protocol adherence). The workers scored their increase in knowledge from 0–10 with regard to health status and work ability, their satisfaction with the intervention and the perceived (future) effect of such an intervention. Program implementation was defined as the mean score of reach, fidelity, and intervention dose delivered and received.

Results

Reach was 9% (77 workers participated), fidelity was 67%, the intervention dose delivered was 92 and 63%, and the intervention dose received was 68 and 49%. The total programme implementation was 58%. The increases in knowledge regarding the health status and work ability of the workers after the WHS were graded as 7.0 and 5.9, respectively. The satisfaction of the workers with the entire intervention was graded as 7.5. The perceived (future) effects on health status were graded as 6.3, and the effects on work ability were graded with a 5.2. The economic recession affected the workers as well as the occupational health service that enacted the implementation.

Conclusions

Programme implementation was acceptable. Low reach, limited protocol adherence and modest engagement of the workers with respect to the intervention were the most prominent aspects that influenced the intervention process. The increase in the workers’ knowledge about their health status and work ability was substantial, and the workers’ satisfaction with the intervention was good. The perceived effect of the advised preventive actions on health status was sufficient.

Trial registration

Netherlands Trial Register: http://NTR3012