Industrial noise exposure, noise annoyance, and serum lipid levels in blue-collar workers--the CORDIS Study

A Systematic Review and Meta-Analysis of Noise Annoyance as a Determinant of Physiological Changes Linked to Disease Promotion

This systematic review investigates the certainty of evidence (CoE) regarding noise annoyance as a determinant of biological changes known to contribute to disease development. We searched PubMed MEDLINE, EMBASE, Cochrane Central, and CINAHL for English-language comparative studies conducted on humans of any age from 1 January 1940, to 28 August 2023. Further, studies that provided quantitative data on the relationship between noise annoyance and biomarkers of interest were included. Where possible, random-effects meta-analyses were used to calculate the odds ratios of noise annoyance on biomarkers and biological conditions considered to be risk factors for developing health effects. The risk of bias of individual studies was assessed using the Risk of Bias of Non-randomized Studies of Exposures (ROBINS-E) instrument. The CoE for each outcome was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The search identified 23 primary studies reporting on relevant biomarkers. Although some studies and pooled estimates suggest a possible association between noise annoyance and biological measures, the CoE overall is very low due to concerns with the risk of bias, inconsistency, and imprecision in the estimates of effects. In the context of environmental impact assessment, where guidelines aim to mitigate the prevalence of populations experiencing a high level of noise annoyance, our results suggest that such practices should be grounded in the understanding that annoyance is health-relevant because it reflects an undesirable reaction to noise, rather than a precursor to chronic physical health conditions.

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

PURPOSE

Noise exposure in the workplace has been linked to a number of health consequences. Our objectives were to explore the relationship between occupational noise and lipid metabolism and evaluate the possible mediating effect of obesity indices in those relationships with a cross-sectional study design.

METHODS

Cumulative noise exposure (CNE) was used to measure the level of noise exposure. Logistic regression models or generalized linear models were employed to evaluate the association of occupational noise and obesity with lipid metabolism markers. Cross-lagged analysis was conducted to explore temporal associations of obesity with lipid metabolism.

RESULTS

A total of 854 participants were included, with each one-unit increase in CNE, the values of total cholesterol/high-density lipoprotein cholesterol and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol increased by 0.013 (95% confidence interval: 0.006, 0.020) and 0.009 (0.004, 0.014), as well as the prevalence of dyslipidemia increased by 1.030 (1.013, 1.048). Occupational noise and lipid metabolism markers were all positively associated with body mass index (BMI), waist circumference (WC), a Body Shape Index (ABSI) and a Body Shape Index and Body Roundness Index (BRI) (all P < 0.05). Moreover, BMI, WC, ABSI and BRI could mediate the associations of occupational noise with lipid metabolism; the proportions ranged from 21.51 to 24.45%, 23.84 to 30.14%, 4.86 to 5.94% and 25.59 to 28.23%, respectively (all P < 0.05).

CONCLUSIONS

Our study demonstrates a positive association between occupational noise and abnormal lipid metabolism, and obesity may partly mediate the association. Our findings reinforce the need to take practical steps to reduce or even eliminate the health risks associated with occupational noise.

Perceiving noise in daily life: How real-time sound characteristics affect personal momentary noise annoyance in various activity microenvironments and times of day

Annoyance is a major health burden induced by environmental noise. However, our understanding of the health impacts of noise is seriously undermined by the fixed contextual unit and limited sound characteristics (e.g., the sound level only) used in noise exposure assessments as well as the stationarity assumption made for exposure-response relationships. To address these limitations, we analyze the complex and dynamic relationships between personal momentary noise annoyance and real-time noise exposure in various activity microenvironments and times of day, taking into account individual mobility, multiple sound characteristics and nonstationary relationships. Using real-time mobile sensing, we collected individual data of momentary noise annoyance, real-time noise exposure as well as daily activities and travels in Hong Kong. A new sound characteristic, namely sound increment, is defined to capture the sudden increase in sound level over time and is used along with the sound level to achieve a multi-faceted assessment of personal real-time noise exposure at the moment of annoyance responses. Further, the complex noise exposure-annoyance relationships are learned using logistic regression and random forest models while controlling the effects of daily activity microenvironments, individual sociodemographic attributes and temporal contexts. The results indicate that the effects of the real-time sound level and sound increment on personal momentary noise annoyance are nonlinear, despite the overall significant and positive impacts, and different sound characteristics can produce a joint effect on annoyance. We also find that the daily activity microenvironments and individual sociodemographic attributes can affect noise annoyance and its relationship with different sound characteristics to varying degrees. Due to the temporal changes in daily activities and travels, the noise exposure-annoyance relationships can also vary over different times of the day. These findings can inform both local governments and residents with scientific evidence to promote the creation of acoustically comfortable living environments.

Investigating the effect of workplace noise exposure on cardiovascular disease risk factors in a power plant industry: A case-control study

BACKGROUND

Occupational noise exposure is a significant health problem. In addition to hearing impairments, noise as a stressor may cause cardiovascular problems.

OBJECTIVE

This study aimed to investigate the effect of exposure to workplace noise on cardiovascular disease risk factors.

METHODS

This case-control study was conducted in 2021 in a power plant in Iran. In this study, the health status of 406 employees in both exposed (n = 203) and non-exposed (n = 203) to noise groups was examined for cardiovascular disease risk factors. Also, the trend of changes in the studied variables from 2012 to 2020 in exposed employees was examined. Data were collected from participants' annual physical examinations and occupational noise exposure measurements. To measure the noise in the present study, the KIMO-DB300 noise level meter was used. Data were analyzed in SPSS-26 software.

RESULTS

The results revealed that mean fasting blood sugar (FBS), triglyceride, liver enzyme (SGOT), blood pressure, and body mass index were significantly different in the two groups (p-value<0.05). There was no significant difference in the mean of creatinine, cholesterol, and liver enzyme (SGPT) between the two groups (p-value>0.05). In the exposed group, the mean of all studied variables except diastolic blood pressure was statistically different during the study years (p-value<0.05).

CONCLUSION

This study demonstrates that exposure to noise above the permissible level can affect the cardiovascular disease risk factors, so it is recommended to apply engineering and management measures like using Hearing Conservation Programme (HCP) to reduce the risk of these diseases with periodically assessing the health status of employees and timely diagnosis.

Assortment of kaempferol and zinc gluconate improves noise-induced biochemical imbalance and deficits in body weight gain

This study investigated the effects of pretreatment with antioxidants, kaempferol, and zinc gluconate on serum biochemical changes and impairment in body weight gain following noise-exposure in Wistar rats. Thirty-five animals were evenly grouped into five cohorts: Groups II, III, IV, and V were exposed to noise stress, induced by exposing rats to 100 dB (4 hr/day) for 15 days, from days 33 to 48 after starting the drug treatments. Treatment with kaempferol and/or zinc mitigated noise-induced deficits in body weight gain, and levels of serum lipid and protein fractions. The combined treatment significantly (p < .05) decreased malondialdehyde concentration in kaempferol + zinc gluconate treated group, compared to the group administered deionized water + noise. This result demonstrates that biochemical dyshomeostasis and lipid peroxidation may be involved in the molecular mechanism underlying noise stress and the assortment of kaempferol and zinc gluconate produced an improved mitigating outcome in Wistar rats.

The prevalence of occupational exposure to noise: 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 network of individual experts. Evidence from mechanistic and human data suggests that occupational exposure to noise may cause cardiovascular disease. In this paper, we present a systematic review and meta-analysis of the prevalence of occupational exposure to noise for estimating (if feasible) the number of deaths and disability-adjusted life years from cardiovascular disease that are attributable to exposure to this risk factor, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the prevalence of occupational exposure to noise.

DATA SOURCES

We searched electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and CISDOC. We also searched electronic grey literature databases, Internet search engines, and organizational websites; hand-searched reference list 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 economies in any WHO Member and/or ILO member State, but excluded children (<15 years) and unpaid domestic workers. We included all study types with an estimate of the prevalence of occupational exposure to noise, categorized into two levels: no (low) occupational exposure to noise (<85dBA) and any (high) occupational exposure to noise (≥85dBA).

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 combined prevalence estimates using random-effect meta-analysis. Two or more review authors assessed the risk of bias and the quality of evidence, using the RoB-SPEO tool and QoE-SPEO approach developed specifically for the WHO/ILO Joint Estimates.

RESULTS

Sixty-five studies (56 cross-sectional studies and nine cohort studies) met the inclusion criteria, comprising 157,370 participants (15,369 females) across 28 countries and all six WHO regions (Africa, Americas, Eastern Mediterranean, Europe, South-East Asia, and Western Pacific). For the main analyses, we prioritized the four included studies that surveyed national probability samples of general populations of workers over the 58 studies of workers in industrial sectors and/or occupations with relatively high occupational exposure to noise. The exposure was generally assessed with dosimetry, sound level meter, or official or company records; in the population-based studies, it was assessed with validated questions. Estimates of the prevalence of occupational exposure to noise are presented for all 65 included studies, by country, sex, 5-year age group, industrial sector, and occupation where feasible. The pooled prevalence of any (high) occupational exposure to noise (≥85dBA) among the general population of workers was 0.17 (95% confidence interval 0.16 to 0.19, 4 studies, 108,256 participants, 38 countries, two WHO regions, I2 98%, low quality of evidence). Subgroup analyses showed that pooled prevalence differed substantially by WHO region, sex, industrial sector, and occupation.

CONCLUSIONS

Our systematic review and meta-analysis found that occupational exposure to noise is prevalent among general populations of workers. The current body of evidence is, however, of low quality, due to serious concerns for risk of bias and indirectness. Producing estimates of occupational exposure to noise nevertheless appears evidence-based, and the pooled effect estimates presented in this systematic review are suitable as input data for the WHO/ILO Joint Estimates (if feasible). Protocol identifier: 10.1016/j.envint.2018.09.040 PROSPERO registration number: CRD42018092272.

Occupational noise exposure and the prevalence of dyslipidemia in a cross-sectional study

BACKGROUND

Occupational noise exposure was related to cardiovascular disease, of which dyslipidemia was an important inducement. This study investigated the relationship between occupational noise exposure and dyslipidemia.

METHODS

Four hundred ninety-two occupational noise-exposed workers and 664 non-exposed workers were recruited to conduct environmental noise tests and personal occupational physical examinations. A lasso-logistic regression model was used to estimate the relative risk of dyslipidemia. A restricted cubic spline was used to estimate the association between noise exposure years and dyslipidemia after adjusting for potential confounding factors.

RESULTS

A crude association was observed between the occupational noise exposure (75-85 dB(A)) and dyslipidemia. After adjusting for confounding factors, there was a non-linear relationship between noise exposure years and dyslipidemia (P for non-linearity =0.01). Workers exposed to 75-85 dB(A) for 11 to 24.5 years had a higher risk of dyslipidemia than non-exposed workers.

CONCLUSIONS

A positive and non-linear exposure-response relationship was found in workers exposed to 75-85 dB(A) whose exposure years were between 11 and 24.5. Workers had the highest risk of dyslipidemia when exposed for 13.5 years.

Noise exposure limit for children in recreational settings: Review of available evidence

It is universally recognized that prolonged exposure to high levels of non-impulsive noise will lead to noise-induced hearing loss. These high levels of noise have traditionally been found in an occupational setting, but exposure to high levels of noise is increasingly common in recreational settings. There is currently no established acceptable risk of hearing loss in children. This review assumed that the most appropriate exposure limit for recreational noise exposure in children would be developed to protect 99% of children from hearing loss exceeding 5 dB at the 4 kHz audiometric test frequency after 18 years of noise exposure. Using the ISO 1999:2013 model for predicting hearing loss, it was estimated that noise exposure equivalent to an 8-h average exposure (L_EX) of 82 dBA would result in about 4.2 dB or less of hearing loss in 99% of children after 18 years of exposure. The 8-h L_EX was reduced to 80 dB to include a 2 dB margin of safety. This 8-h L_EX of 80 dBA is estimated to result in 2.1 dB or less of hearing loss in 99% of children after 18 years of exposure. This is equivalent to 75 dBA as a 24-h equivalent continuous average sound level.

Blue-collar work and women's health: A systematic review of the evidence from 1990 to 2015

Despite the implications of gender and sex differences for health risks associated with blue-collar work, adverse health outcomes among blue-collar workers has been most frequently studied among men. The present study provides a "state-of-the-field" systematic review of the empiric evidence published on blue-collar women's health. We systematically reviewed literature related to the health of blue-collar women published between January 1, 1990 and December 31, 2015. We limited our review to peer-reviewed studies published in the English language on the health or health behaviors of women who were presently working or had previously worked in a blue-collar job. Studies were eligible for inclusion regardless of the number, age, or geographic region of blue-collar women in the study sample. We retained 177 studies that considered a wide range of health outcomes in study populations from 40 different countries. Overall, these studies suggested inferior health among female blue-collar workers as compared with either blue-collar males or other women. However, we noted several methodological limitations in addition to heterogeneity in study context and design, which inhibited comparison of results across publications. Methodological limitations of the extant literature, alongside the rapidly changing nature of women in the workplace, motivate further study on the health of blue-collar women. Efforts to identify specific mechanisms by which blue-collar work predisposes women to adverse health may be particularly valuable in informing future workplace-based and policy-level interventions.

[Environmental noise levels in 2 intensive care units in a tertiary care centre]

INTRODUCTION

The World Health Organisation (WHO) has established a maximum noise level of 40 decibels (dB) for an intensive care unit. The aim of this study was to compare the noise levels in 2 different intensive care units at a tertiary care centre.

METHODS

Using a cross-sectional design study, an analysis was made of the maximum noise level was within the intensive coronary care unit and intensive care unit using a digital meter. A measurement was made in 4 different points of each room, with 5minute intervals, for a period of 60minutes 7:30, 14:30, and 20:30. The means of the observations were compared with descriptive statistics and Mann-Whitney U. An analysis with Kruskal-Wallis test was performed to the mean noise level.

RESULTS

The noise observed in the intensive care unit had a mean of 64.77±3.33dB (P=.08), which was similar to that in the intensive coronary care unit, with a mean of 60.20±1.58dB (P=.129). Around 25% or more of the measurements exceeded the level recommended by the WHO by up to 20 points.

CONCLUSIONS

Noise levels measured in intensive care wards exceed the maximum recommended level for a hospital. It is necessary to design and implement actions for greater participation of health personnel in the reduction of environmental noise.

Ambient and at-the-ear occupational noise exposure and serum lipid levels

OBJECTIVES

Occupational and residential noise exposure has been related to increased risk of cardiovascular disease. Alteration of serum lipid levels has been proposed as a possible causal pathway. The objective of this study was to investigate the relation between ambient and at-the-ear occupational noise exposure and serum levels of total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides when accounting for well-established predictors of lipid levels.

METHODS

This cross-sectional study included 424 industrial workers and 84 financial workers to obtain contrast in noise exposure levels. They provided a serum sample and wore portable dosimeters that every 5-s recorded ambient noise exposure levels during a 24-h period. We extracted measurements obtained during work and calculated the full-shift mean ambient noise level. For 331 workers who kept a diary on the use of a hearing protection device (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the mean full-shift noise exposure level at the ear.

RESULTS

Mean ambient noise level was 79.9 dB (A) [range 55.0-98.9] and the mean estimated level at the ear 77.8 dB (A) [range 55.0-94.2]. Ambient and at-the-ear noise levels were strongly associated with increasing levels of triglycerides, cholesterol-HDL ratio, and decreasing levels of HDL-cholesterol, but only in unadjusted analyses that did not account for HPD use and other risk factors.

CONCLUSION

No associations between ambient or at-the-ear occupational noise exposure and serum lipid levels were observed. This indicates that a causal pathway between occupational and residential noise exposure and cardiovascular disease does not include alteration of lipid levels.

The Effect of Occupational Noise Exposure on Blood and Biochemical Parameters: A Case Study of an Insulator Manufacturer in Iran

Introduction

Occupational noise is among the most critical occupational hazards, which, in addition to hearing loss, can cause other adverse consequences on an individual’s physical and mental health. Long-term exposure to noise can affect blood and biochemical parameters and subsequently lead to increased risk of cardiovascular disease. This study investigated the effect of occupational exposure to noise on blood and biochemical parameters of workers in an insulator manufacturing plant.

Methods

This case-control study was conducted on workers in the production section (49 people as a case group) and the administrative staff (10 people as a control group) in one insulator manufacturing plant from 2010 to 2014. To assess individual exposure of workers to noise, the noise dosimeter model TES-1355 was used. Noise dosimetry testing was done based on the exposure pattern of workers to noise in compliance with the Iranian national standard (the criterion level of 85 dBA and the exchange rate of Q = 3 dBA). Blood parameters such as blood glucose, cholesterol, red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), and hematocrit (Hct) were studied in production workers (case) and administrative staff (control) over five consecutive years. The data were analyzed by software (SPSS-22) using the t-test, Mann-Whitney test, Fisher exact test, and Greenhouse-Geisser test.

Results

No significant difference was found among the demographic data of the two groups (p > 0.05). Average of glucose and cholesterol levels in the two groups was statistically significant (p < 0.05) and blood glucose levels in the case group significantly reduced over time and cholesterol increased (p < 0.001). Mean difference of RBC number, WBC number, and serum levels of Hb and Hct was statistically significant between the two groups (p < 0.05). In addition, these hematological parameters increased among workers during these years.

Conclusion

Occupational exposure to noise may have a significant effect on an individual’s blood parameters, which will cause harmful effects on worker health. Therefore, industrialists must take preventive measures in the field of noise control.

Changes in Guinea pig cochlear hair cells after sound conditioning and noise exposure

Sound conditioning has reduced noise-induced hearing loss in experimental mammalian animals and in clinical observation. Forty guinea pigs were grouped as: A, control; B, conditioning noise exposure group; C, high level noise exposure group; and D, conditioning noise exposure followed by a high level noise exposure group. Auditory brainstem response thresholds were measured. The cochlear sensory epithelia surface was observed microscopically. Calmodulin, F-actin and heat shock protein 70 (HSP70) in hair cells were immunohistochemistrically stained. The intracellular free calcium was stained for confocal microscopy. The ABR threshold shift after noise exposure was higher in group C than D, and showed a quicker and better recovery in group D than C. Stereocilia loss and the disarrangement of outer hair cells were observed, with the greatest changes seen in group C, followed by groups D and B. The most intensive immunohistochemical intracellular expressions of calmodulin, F-actin, and HSP70 were found in group D, followed by groups C, B and A. The highest intensity of the fluorescent intracellular free Ca2+ staining in the isolated outer hair cells was observed in group C. The ABR and morphological studies confirmed the protective effect from noise trauma of sound conditioning. The protective mechanism of hair cells during sound conditioning was enforced through the increase of cellular cytoskeleton proteins and through the relieving of intracellular calcium overloading caused by the traumatic noise.

Effects of alpha-tocopherol on noise-induced hearing loss in guinea pigs

Preventing noise-induced hearing loss (NIHL) by antioxidants is based on the hypothesis that generation of reactive oxygen species is one of the causes of NIHL. alpha-Tocopherol is a naturally occurring antioxidant with no noticeable side effects. In this study, we attempted to protect guinea pigs from developing NIHL by administering alpha-tocopherol. Pigmented male guinea pigs were exposed to a noise (4 kHz octave band, 100 dB SPL), 8 h/day for 3 days consecutively. alpha-Tocopherol (10 mg/kg or 50 mg/kg daily) was given by intraperitoneal injection from 3 days before through 3 days after the noise exposure. Auditory evoked brainstem response (ABR) thresholds at 2, 4 and 8 kHz were recorded prior to the experiment, immediately post-noise, 2 and 8 days post-noise. On day 8 post-noise, after the ABR recording, guinea pigs were decapitated and the cochleae were removed for cochlear surface preparations and scanning electron microscope (SEM) study. ABR threshold shifts of groups receiving alpha-tocopherol were significantly smaller than those of groups not receiving alpha-tocopherol at all frequencies and all time points tested except that of group 3 at 8 kHz 8 days post-noise. No hair cell loss was seen on the surface preparations, but stereocilia loss was found by SEM study. The noise-induced stereocilia loss was significantly decreased by alpha-tocopherol. These results indicate that alpha-tocopherol can attenuate the noise-induced cochlear damage. Further investigations on the preventive effect of alpha-tocopherol on NIHL in noise-exposed workers are necessary.

Noise pollution: non-auditory effects on health

Noise is a prominent feature of the environment including noise from transport, industry and neighbours. Exposure to transport noise disturbs sleep in the laboratory, but not generally in field studies where adaptation occurs. Noise interferes in complex task performance, modifies social behaviour and causes annoyance. Studies of occupational and environmental noise exposure suggest an association with hypertension, whereas community studies show only weak relationships between noise and cardiovascular disease. Aircraft and road traffic noise exposure are associated with psychological symptoms but not with clinically defined psychiatric disorder. In both industrial studies and community studies, noise exposure is related to raised catecholamine secretion. In children, chronic aircraft noise exposure impairs reading comprehension and long-term memory and may be associated with raised blood pressure. Further research is needed examining coping strategies and the possible health consequences of adaptation to noise.

The influence of stressors on biochemical reactions--a review of present scientific findings with noise

For every faculty of perception there is, according to the degree of irritation, a biochemical or psychobiological activation. This is also true for the perception of sound or noise. Initially, these processes allow for the adjustment of the organism to a changed situation (eustress). Prolonged effects of stressors may ultimately lead to regulatory disturbances and induce pathological processes (distress). The pathogenetic concept that psychobiological stresses (e.g. noise) may be connected with the well-known risk factors of cardiovascular diseases, through excitation of the central nervous system, is based on the known stress models. The central connective factors are the activation hormones of the adrenal gland, also referred to as stress hormones. From blood and urine parameters recorded in epidemiological and experimental studies under the influence of acute or chronic noise, a simplified model of the pathogenetic mechanism has been developed. Fundamental conditions for future assessing the "stress hormones" have been derived, by means of which premorbid conditions can be determined on a population or group basis.