The joint effect of noise exposure and job complexity on distress and injury risk among men and women: the cardiovascular occupational risk factors determination in Israel study

The Effect of Noise on the Neurobehavioral Function of the Occupational Population and the Content of Catecholamines

According to the decibel level of noise detection in the working environment, the research objects were divided into high noise group (more than 85 dB), low noise group (55 to 85 dB), and control group (less than 55 dB), the neurobehavioral core test battery (NCTB) was used to systematic tests all workers, radioimmunoassay was used to detect plasma catecholamine levels, and the relationship between noise intensities and the levels of plasma catecholamine was analyzed by canonical correlation. The result shows noise exposure will affect workers' neurological function and the influence of noise on neurobehavioral function may be related to the increase of the levels of norepinephrine and dopamine in the plasma and the inhibition of the synthesis of epinephrine of noise-exposed workers.

The effect of occupational exposure to noise on ischaemic heart disease, stroke and hypertension: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-Related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large number of individual experts. Evidence from mechanistic data suggests that occupational exposure to noise may cause cardiovascular disease (CVD). In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from CVD that are attributable to occupational exposure to noise, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of any (high) occupational exposure to noise (≥85 dBA), compared with no (low) occupational exposure to noise (<85 dBA), on the prevalence, incidence and mortality of ischaemic heart disease (IHD), stroke, and hypertension.

DATA SOURCES

A protocol was developed and published, applying the Navigation Guide as an organizing systematic review framework where feasible. We searched electronic academic databases for potentially relevant records from published and unpublished studies up to 1 April 2019, including International Trials Register, Ovid MEDLINE, PubMed, Embase, Lilacs, Scopus, Web of Science, and CISDOC. The MEDLINE and Pubmed searches were updated on 31 January 2020. We also searched grey literature databases, Internet search engines and organizational websites; hand-searched reference lists of previous systematic reviews and included study records; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State but excluded children (<15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of any occupational exposure to noise on CVD prevalence, incidence or mortality, compared with the theoretical minimum risk exposure level (<85 dBA).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. We prioritized evidence from cohort studies and combined relative risk estimates using random-effect meta-analysis. To assess the robustness of findings, we conducted sensitivity analyses (leave-one-out meta-analysis and used as alternative fixed effects and inverse-variance heterogeneity estimators). At least two review authors assessed the risk of bias, quality of evidence and strength of evidence, using Navigation Guide tools and approaches adapted to this project.

RESULTS

Seventeen studies (11 cohort studies, six case-control studies) met the inclusion criteria, comprising a total of 534,688 participants (39,947 or 7.47% females) in 11 countries in three WHO regions (the Americas, Europe, and the Western Pacific). The exposure was generally assessed with dosimetry, sound level meter and/or official or company records. The outcome was most commonly assessed using health records. We are very uncertain (low quality of evidence) about the effect of occupational exposure to noise (≥85 dBA), compared with no occupational exposure to noise (<85 dBA), on: having IHD (0 studies); acquiring IHD (relative risk (RR) 1.29, 95% confidence interval (95% CI) 1.15 to 1.43, two studies, 11,758 participants, I² 0%); dying from IHD (RR 1.03, 95% CI 0.93-1.14, four studies, 198,926 participants, I² 26%); having stroke (0 studies); acquiring stroke (RR 1.11, 95% CI 0.82-1.65, two studies, 170,000 participants, I² 0%); dying from stroke (RR 1.02, 95% CI 0.93-1.12, three studies, 195,539 participants, I² 0%); having hypertension (0 studies); acquiring hypertension (RR 1.07, 95% CI 0.90-1.28, three studies, four estimates, 147,820 participants, I² 52%); and dying from hypertension (0 studies). Data for subgroup analyses were missing. Sensitivity analyses supported the main analyses.

CONCLUSIONS

For acquiring IHD, we judged the existing body of evidence from human data to provide "limited evidence of harmfulness"; a positive relationship is observed between exposure and outcome where chance, bias, and confounding cannot be ruled out with reasonable confidence. For all other included outcomes, the bodies of evidence were judged as "inadequate evidence of harmfulness". Producing estimates for the burden of CVD attributable to occupational exposure to noise appears to not be evidence-based at this time.

PROTOCOL IDENTIFIER

10.1016/j.envint.2018.09.040.

PROSPERO REGISTRATION NUMBER

CRD42018092272.

Work-life prevalence of self-reported occupational injuries in mothers of a birth cohort

Purpose. This study investigated self-reported occupational injuries among mothers in a large birth cohort study and the relation of their characteristics to different injury outcomes: occurrence, severity, temporal proximity and recurrence. Methods. We asked 4338 women whether they had been in 'an accident at work, even if it did not require medical treatment', and the number of accidents throughout their working life, type of injury and whether it occurred within the last 12 months. Results. Over one-fifth (21.8%) of working-age mothers reported having at least one occupational injury throughout their working life. Wounds and superficial injuries were the most frequently reported types of occupational injuries (11.0%), followed by dislocated bones and joints, sprains and strains (10.7%). Women who reported a history of occupational injuries also had a higher likelihood of reporting a work-related health problem (adjusted odds ratio [OR] = 2.64; 95% confidence interval [CI] [2.27, 3.07]) and of having a partner who also reported an occupational injury throughout their working life (adjusted OR = 1.86; 95% CI [1.33, 2.62]). Associations remained fairly stable across all outcomes. Conclusions. Our findings point towards a broadened understanding of occupational injury consequences and research focusing on family-level factors that account for the embeddedness of workers in households.

WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of exposure to occupational noise and of the effect of exposure to occupational noise on cardiovascular disease

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury (WHO/ILO joint methodology), with contributions from a large network of experts. In this paper, we present the protocol for two systematic reviews of parameters for estimating the number of deaths and disability-adjusted life years from cardiovascular disease attributable to exposure to occupational noise, to inform the development of the WHO/ILO joint methodology.

OBJECTIVES

We aim to systematically review studies on exposure to occupational noise (Systematic Review 1) and systematically review and meta-analyse estimates of the effect of occupational noise on cardiovascular diseases (Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework, conducting both systematic reviews in tandem and in a harmonized way.

DATA SOURCES

Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science and CISDOC. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand search reference list of previous systematic reviews and included study records; and consult additional experts.

STUDY ELIGIBILITY AND CRITERIA

We will include working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State, but exclude children (<15 years) and unpaid domestic workers. The eligible risk factor will be occupational noise. Eligible outcomes will be hypertensive heart disease, ischaemic heart disease, stroke, cardiomyopathy, myocarditis, endocarditis and other circulatory diseases. For Systematic Review 1, we will include quantitative prevalence studies of exposure to occupational noise (i.e., low: <85 dB(A) and high: ≥85 dB(A)) stratified by country, sex, age and industrial sector or occupation. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the relative effect of high exposure to occupational noise on the prevalence of, incidence of or mortality due to cardiovascular disease, compared with the theoretical minimum risk exposure level (i.e., low exposure).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2. PROSPERO registration number: CRD42018092272.

Development of a Job Exposure Matrix for Noise in the Swedish Soft Tissue Paper Industry

Objectives

Noise exposure is a common occupational hazard, but has not been sufficiently characterized in paper mills. We developed a job-exposure matrix (JEM) for noise exposure for use in estimating exposures among Swedish soft tissue paper mill workers.

Methods

We used a combination of area and personal dosimetry noise exposure measurements made at four soft tissue paper mills by industry and research staff between 1977 and 2013 to estimate noise exposures by department, location, and job title. We then utilized these estimates, in conjunction with information on process and facility changes and use of hearing protection collected via focus groups, to create a seven-category, semi-quantitative JEM for all departments, locations, and job titles spanning the years 1940–2010.

Results

The results of the 1157 area and personal dosimetry noise measurements indicated that noise levels have generally declined in Swedish paper mills over time, though these changes have been neither uniform nor monotonic within or across the four mills. Focus group results indicated that use of hearing protection has generally increased over time. The noise JEM totals 1917 cells, with each cell representing a unique combination of operation, job title, and single year. We estimated that ~50% of workers at the four mills assessed were exposed at or above the Swedish 8-h average noise exposure limit of an 85 dBA at the conclusion of the study period in 2010.

Conclusions

Our results highlight the continuing need for hearing loss prevention and noise control efforts at these and similar mills, and the completed JEM now represents a tool for use in epidemiological studies of noise-related health outcomes.

The risk of occupational injury increased according to severity of noise exposure after controlling for occupational environment status in Korea

Objectives:

The aim of this study was to examine the relationship between noise exposure and risk of occupational injury.

Materials and Methods:

Korean National Health and Nutrition Examination Survey was used for the current study. Self-report questionnaires were used to investigate occupational injury and exposure to noise, chemicals, and machines and equipments.

Results:

In separate analyses for occupation and occupational hazard, the proportion of occupational injuries increased according to severity of noise exposure (all P < 0.05). Compared to the non-exposure group, the respective odds ratio (95% confidence intervals) for occupational injury was 1.39 (1.07–1.80) and 1.67 (1.13–2.46) in the mild and severe noise exposure groups, after controlling for age, gender, sleep hours, work schedule (shift work), and exposure status to hazardous chemicals and hazardous machines and equipments.

Conclusions:

The current study highlights the association between noise exposure and risk of occupational injury. Furthermore, risk of occupational injury increased according to severity of noise exposure.

Disorders induced by direct occupational exposure to noise: Systematic review

Background:

To review the available scientific literature about the effects on health by occupational exposure to noise.

Materials and Methods:

A systematic review of the retrieved scientific literature from the databases MEDLINE (via PubMed), ISI-Web of Knowledge (Institute for Scientific Information), Cochrane Library Plus, SCOPUS, and SciELO (collection of scientific journals) was conducted. The following terms were used as descriptors and were searched in free text: “Noise, Occupational,” “Occupational Exposure,” and “Occupational Disease.” The following limits were considered: “Humans,” “Adult (more than 18 years),” and “Comparative Studies.”

Results:

A total of 281 references were retrieved, and after applying inclusion/exclusion criteria, 25 articles were selected. Of these selected articles, 19 studies provided information about hearing disturbance, four on cardiovascular disorders, one regarding respiratory alteration, and one on other disorders.

Conclusions:

It can be interpreted that the exposure to noise causes alterations in humans with different relevant outcomes, and therefore appropriate security measures in the work environment must be employed to minimize such an exposure and thereby to reduce the number of associated disorders.

Do Personal Factors or Types of Physical Tasks Predict Workplace Injury?

Occupational health research has shown that certain worker and job characteristics are risk factors for workplace injuries. Workers who engage in physically demanding jobs, especially those jobs that involve repetitive motion, are at greater risk for work-related musculoskeletal disorders (WMSD). These risks are particularly prevalent in the health care sector. It is often reported that nurses are at higher risk of workplace musculoskeletal injury than other health care workers due to frequent lifting and transfer of patients and the prevalence of workplace violence. However, many analyses of the physical requirements of jobs do not consider the modifying effect of time spent on a physical task and the risk of WMSD. This study compared the risks of WMSD among workers in health care facilities based on the type of physical tasks and amount of time workers spent on such tasks. Workers who worked longer on a physical task reported more WMSD than those who spent less time on the same physical task. The risk of WMSD was twice as high (odds ratio [OR] = 2.3) among workers who sit less than 2 hours each day compared with those who sit longer. This study found that physical tasks associated with health care jobs and the amount of time spent on these tasks constitutes serious risk factors for WMSD.

Noise and neurotoxic chemical exposure relationship to workplace traumatic injuries: A review

INTRODUCTION

More than 5,000 fatalities and eight million injuries occurred in the workplace in 2007 at a cost of $6 billion and $186 billion, respectively. Neurotoxic chemicals are known to affect central nervous system functions among workers, which include balance and hearing disorders. However, it is not known if there is an association between exposure to noise and solvents and acute injuries.

METHOD

A thorough review was conducted of the literature on the relationship between noise or solvent exposures and hearing loss with various health outcomes.

RESULTS

The search resulted in 41 studies. Health outcomes included: hearing loss, workplace injuries, absence from work due to sickness, fatalities, hospital admissions due to workplace accidents, traffic accidents, hypertension, balance, slip, trips, or falls, cognitive measures, or disability retirement. Important covariates in these studies were age of employee, type of industry or occupation, or length of employment.

DISCUSSION

Most authors that evaluated noise exposure concluded that higher exposure to noise resulted in more of the chosen health effect but the relationship is not well understood. Studies that evaluated hearing loss found that hearing loss was related to occupational injury, disability retirement, or traffic accidents. Studies that assessed both noise exposure and hearing loss as risk factors for occupational injuries reported that hearing loss was related to occupational injuries as much or more than noise exposure. Evidence suggests that solvent exposure is likely to be related to accidents or other health consequences such balance disorders.

CONCLUSIONS

Many authors reported that noise exposures and hearing loss, respectively, are likely to be related to occupational accidents. Practical applications: The potential significance of the study is that findings could be used by managers to reduce injuries and the costs associated with those injures.

Injury Risk and Noise Exposure in Firefighter Training Operations

INTRODUCTION

Firefighters have high rate of injuries and illnesses, as well as exposures to high levels of noise. This study explored the relationship between noise exposure and injury among firefighters.

METHODS

We recruited firefighters undergoing vehicle extrication and structural collapse emergency response training at a highly realistic training facility. Demographics, health status, body mass index (BMI), and history of serious injuries (i.e. injuries requiring first aid treatment, treatment in a medical clinic or office, or treatment at a hospital) were assessed at baseline, and daily activities, injury events, and near misses were assessed daily via surveys. Participants' noise exposures were monitored for one 24-h period using noise dosimeters. We used a mixed-effects logistic regression model to estimate the odds of injury events and near misses associated with noise exposure as an independent variable.

RESULTS

Of 56 subjects, 20 (36%) reported that they had ever suffered a serious injury during firefighting activities, and 9 (16%) reported a serious injury within the past year. We estimated rates of 6.6 lifetime serious injuries per 100 FTE 16.1 serious injuries per 100 FTE within the past year. Our models indicated a significant increase in injury events and near misses among those with higher BMI, and as well as a dose-response relationship between near misses/injuries and increasing noise levels. Noise levels >90 dBA in the 30 min prior to time of injury or near miss were associated with substantially increased odds ratios for injury or near miss. Our models further indicated that perceived job demands were significantly associated with increased risk of injury or near miss.

CONCLUSION

Our results suggest that noise exposures may need to be incorporated into injury prevention programs for firefighters to reduce injuries among this high-risk occupational group.

Effectiveness evaluation of existing noise controls in a deep shaft underground mine

Noise exposures and hearing loss in the mining industry continue to be a major problem, despite advances in noise control technologies. This study evaluated the effectiveness of engineering, administrative, and personal noise controls using both traditional and in-ear dosimetry by job task, work shift, and five types of earplug. The noise exposures of 22 miners performing deep shaft-sinking tasks were evaluated during 56 rotating shifts in an underground mine. Miners were earplug-insertion trained, earplug fit-tested, and monitored utilizing traditional and in-ear dosimetry. The mean TWA8 noise exposure via traditional dosimetry was 90.1 ± 8.2 dBA, while the mean in-ear TWA8 was 79.6 ± 13.8 dBA. The latter was significantly lower (p < 0.05) than the Mine Safety and Health Administration (MSHA) personal exposure limit (PEL) of 90 dBA. Dosimetry mean TWA8 noise exposures for bench blowing (103.5 ± 0.9 dBA), jumbo drill operation (103.0 ± 0.8 dBA), and mucking tasks (99.6 ± 4.7 dBA) were significantly higher (p < 0.05) than other tasks. For bench blowing, cable pulling, grinding, and jumbo drill operation tasks, the mean in-ear TWA8 was greater than 85 dBA. Those working swing shift had a significantly higher (p < 0.001) mean TWA8 noise exposure (95.4 ± 7.3 dBA) than those working day shift. For percent difference between traditional vs. in-ear dosimetry, there was no significant difference among types of earplug used. Reflective of occupational hearing loss rate trends across the mining industry, this study found that, despite existing engineering and administrative controls, noise exposure levels exceeded regulatory limits, while the addition of personal hearing protection limited excessive exposures.

Gender inequalities in occupational health related to the unequal distribution of working and employment conditions: a systematic review

Introduction

Gender inequalities exist in work life, but little is known about their presence in relation to factors examined in occupation health settings. The aim of this study was to identify and summarize the working and employment conditions described as determinants of gender inequalities in occupational health in studies related to occupational health published between 1999 and 2010.

Methods

A systematic literature review was undertaken of studies available in MEDLINE, EMBASE, Sociological Abstracts, LILACS, EconLit and CINAHL between 1999 and 2010. Epidemiologic studies were selected by applying a set of inclusion criteria to the title, abstract, and complete text. The quality of the studies was also assessed. Selected studies were qualitatively analysed, resulting in a compilation of all differences between women and men in the prevalence of exposure to working and employment conditions and work-related health problems as outcomes.

Results

Most of the 30 studies included were conducted in Europe (n=19) and had a cross-sectional design (n=24). The most common topic analysed was related to the exposure to work-related psychosocial hazards (n=8). Employed women had more job insecurity, lower control, worse contractual working conditions and poorer self-perceived physical and mental health than men did. Conversely, employed men had a higher degree of physically demanding work, lower support, higher levels of effort-reward imbalance, higher job status, were more exposed to noise and worked longer hours than women did.

Conclusions

This systematic review has identified a set of working and employment conditions as determinants of gender inequalities in occupational health from the occupational health literature. These results may be useful to policy makers seeking to reduce gender inequalities in occupational health, and to researchers wishing to analyse these determinants in greater depth.

The Italian Version of the Weinstein Noise Sensitivity Scale

The Weinstein’s Noise Sensitivity Scale (WNSS) is one of the most widely used questionnaires to measure noise sensitivity, the most important subjective factor moderating the impact of noise on perceived annoyance. The present study evaluates the psychometric properties of the Italian version of the WNSS, tests the measurement invariance of this scale as a function of internal and external factors, and evaluates the effect of age, sex, and context on noise sensitivity. The scale was administered to a sample of 413 adults (40% females) living in quiet or noisy contexts. Dimensionality, reliability, invariance, validity, and equivalence were analyzed. Results confirmed that the WNSS is a reliable, valid, and invariant scale. Furthermore, noise sensitivity is affected by both subjective factors, such as age and sex, and external factors, such as living context.

[Level of noise at the workplace environment among physical education teachers in indoor bike classes]

OBJECTIVE

To analyze the level of noise at the workplace environment among Physical Education teachers during indoor bike classes and its association with some aspects of health.

METHODS

Cross-sectional study carried out in 15 different gyms with 15 teachers in Rio de Janeiro (Southeastern Brazil) in 2007. A standardized questionnaire, tested in relation to its replication, was used in order to find out the characteristics of the process and the way this job is organized, as well as complaints related to health reported by these teachers. The SRQ-20 (Self-Report Questionnaire) was utilized in order to verify the existence of minor psychiatric disturbances. The levels of sound pressure were measured by a portable appliance. The level of pressure was verified in dB(A) at equivalent energy levels (Leq) in different places of the room at different moments during the class. ANOVA, chi-square and Pearson's correlation analyses were performed.

RESULTS

The levels of sound pressure varied from 74.4 dB(A) to 101.6 dB(A). The results during the class were: a) warm-up (mean=88.45 dB(A)); b) main part (mean= 95.86 dB(A)); and, closure (mean= 85.12 dB(A)). The mean background noise was 66.89 dB(A)). There were significant differences (p<0.001) among the background noise levels within different moments of the class. The noise was not related to minor psychiatric disturbances.

CONCLUSIONS

Physical education professionals working with indoor bike classes are under high levels of sound pressure during their classes. This physical agent has been related to several health problems and should therefore be more controlled.

Could driving safety be compromised by noise exposure at work and noise-induced hearing loss?

OBJECTIVE

A study was conducted to verify if there is an association between occupational noise exposure, noise-induced hearing loss and driving safety expanding on previous findings by Picard, et al. (2008) that the two factors did increase accident risk in the workplace.

METHODS

This study was made possible when driving records of all Quebec drivers were made available by the Societe de l'assurance automobile du Quebec (SAAQ is the state monopoly responsible for the provision of motor vehicle insurance and the compensation of victims of traffic accidents). These records were linked with personal records maintained by the Quebec National Institute of Public Health as part of its mission to prevent noise induced hearing loss in the workplace. Individualized information on occupational noise exposure and hearing sensitivity was available for 46,030 male workers employed in noisy industries who also held a valid driver's permit. The observation period is of five years duration, starting with the most recent audiometric examination. The associations between occupational noise exposure levels, hearing status, and personal driving record were examined by log-binomial regression on data adjusted for age and duration of exposure. Daily noise exposures and bilateral average hearing threshold levels at 3, 4, and 6 kHz were used as independent variables while the dependent variables were 1) the number of motor vehicle accidents experienced by participants during the study period and 2) participants' records of registered traffic violations of the highway safety code. The findings are reported as prevalence ratios (PRs) with their 95% confidence intervals (CIs). Attributable numbers of events were computed with the relevant PRs, lesser-noise, exposed workers and those with normal hearing levels making the group of reference.

RESULTS

Adjusting for age confirmed that experienced workers had fewer traffic accidents. The data show that occupational noise exposure and hearing loss have the same effect on driving safety record than that reported on the risk of accident in noisy industrial settings. Specifically, the risk of traffic accident (PR = 1.07 (CI 95% [1.01; 1.15]) is significantly associated with the daily occupational noise exposures >or= 100 dBA. For participants having a bilateral average hearing loss ranging from 16 to 30 dB, the PR of traffic accident is 1.06 (CI 95% [1.01; 1.11]) and reaches 1.31 (CI 95% [1.2; 1.42]) when the hearing loss exceeds of 50 dB. A reduction in the number of speeding violations occurred among workers occupationally exposed to noise levels >or= 90 dBA and those with noise-induced hearing loss >or=16 dB. By contrast, the same individuals had an increase in other violations of the Highway safety code. This suggests that noise-exposed workers might be less vigilant to other traffic hazards.

CONCLUSION

Daily occupational noise exposures >or= 100 dBA and noise-induced hearing losses-even when just barely noticeable-may interfere with the safe operation of motor vehicles.

Association of work-related accidents with noise exposure in the workplace and noise-induced hearing loss based on the experience of some 240,000 person-years of observation

This retrospective study explores the association between occupational noise exposure at the time of hearing tests, permanent noise-induced hearing loss and work-related accident risk. Log-binomial analysis was used to first ascertain the association between study variables according to activity sector (North American Industry Classification System, NAICS) and accident context while controlling for age. Second part of the paper estimates the overall number of accidents attributable to occupational noise or the associated hearing loss (excess fraction). Study was carried on a sample of 52,982 male workers exposed to a minimum of 80 dBA on a daily basis and whose hearing was examined at least once between 1983 and 1996 by public health authorities of Quebec. These participants evidenced bilateral average hearing threshold levels at 3, 4 and 6 kHz ranging from normal (< or = 15 dB) to hearing loss in excess of 50 dB as a result of chronic occupational noise exposure (subjects otherwise otologically normal). The occupational accident count of these workers was derived from the individual histories registered with the Quebec workers' compensation board for the 1983-1998 period. Results show an association between accident risk and worker's hearing sensitivity. For example, a hearing loss of 20 dB corresponds to a rise of accident risk equal to 1.14 when controlling for age and occupational noise exposure at the time of hearing tests. NAICS economic activity sectors where association is the most noticeable are "Metal Transformation", "Metal Product Manufacturing" and "Transportation Equipment Manufacturing". "Passive accidents" (PR per decibel of hearing loss = 1.008; CI 95 (1.007; 1.010)) and "same-level falls" (1.007; CI 95 (1.003; 1.010)) are the two accidents categories most strongly associated with hearing loss. Overall, 12.2% of accidents considered in this study were attributable to a combination of noise exposure in the workplace (> or = 90 dBA) and noise-induced hearing loss.

[Occupational noise exposure and work accidents]

The purpose of this study was to verify whether occupational noise exposure is a significant risk factor for work accidents in the city of Piracicaba, São Paulo State, Brazil. This hospital-based case-control study included 600 workers aged 15-60 who suffered typical occupational accidents between May and October 2004 and were seen at the Piracicaba Orthopedics and Trauma Center. The control group comprised 822 workers, aged 15-60, who were also seen at the Center, and either had a non-occupational accident or were accompanying someone who had suffered an accident. A multiple logistic regression model was adjusted with work accident as an independent variable, controlled by covariables of interest such as noise exposure. The risk of having a work accident was about twice as high among workers exposed to noise, after controlling for several covariables. Occupational noise exposure not only affected auditory health status but was also a risk factor for work accidents.