The effects of chronic industrial noise exposure on urinary cortisol, fatigue and irritability: a controlled field experiment

A Comprehensive Review on Social Inequalities and Pregnancy Outcome-Identification of Relevant Pathways and Mechanisms

Scientific literature tends to support the idea that the pregnancy and health status of fetuses and newborns can be affected by maternal, parental, and contextual characteristics. In addition, a growing body of evidence reports that social determinants, measured at individual and/or aggregated level(s), play a crucial role in fetal and newborn health. Numerous studies have found social factors (including maternal age and education, marital status, pregnancy intention, and socioeconomic status) to be linked to poor birth outcomes. Several have also suggested that beyond individual and contextual social characteristics, living environment and conditions (or "neighborhood") emerge as important determinants in health inequalities, particularly for pregnant women. Using a comprehensive review, we present a conceptual framework based on the work of both the Commission on Social Determinants of Health and the World Health Organization (WHO), aimed at describing the various pathways through which social characteristics can affect both pregnancy and fetal health, with a focus on the structural social determinants (such as socioeconomic and political context) that influence social position, as well as on intermediary determinants. We also suggest that social position may influence more specific intermediary health determinants; individuals may, on the basis of their social position, experience differences in environmental exposure and vulnerability to health-compromising living conditions. Our model highlights the fact that adverse birth outcomes, which inevitably lead to health inequity, may, in turn, affect the individual social position. In order to address both the inequalities that begin in utero and the disparities observed at birth, it is important for interventions to target various unhealthy behaviors and psychosocial conditions in early pregnancy. Health policy must, then, support: (i) midwifery availability and accessibility and (ii) enhanced multidisciplinary support for deprived pregnant women.

Noise exposure and mental workload: Evaluating the role of multiple noise exposure metrics among surface miners in the US Midwest

This study examined associations between metrics of noise exposure and mental workload. In this cross-sectional study, five occupational noise metrics computed from full-shift dosimetry were evaluated among surface mine workers in the US Midwest. Mental workload was evaluated using a modified, raw NASA-TLX and clustered with a k-means clustering algorithm. Mixed effects logistic regression and Bayesian Kernel Machine Regression (BKMR) was utilized for analysis. Average noise exposure, the difference between peak and mean noise exposure, and the number of peaks >135 dB were each strongly associated with mental workload, while the kurtosis and standard deviation of noise throughout a shift were not. An exposure-response relationship between average noise exposure and mental workload may exist, with elevated risk of high mental workload beginning at 80 dBA. These results suggest that high noise exposure may be an independent risk factor of high mental workload, and impulse events and the difference between the peak and mean noise exposure may have interactive effects with average noise exposure.

Hair cortisol as a viable tool for the assessment of an association between environmental noise exposure and chronic stress

Entrenched in the well-established link between stress and health, noise exposure as a potential contributor to stress-related health effects receives tremendous attention. Indeed, exposure to noise can act as a stressor as evidenced through increased heart rate, blood pressure, adrenaline, epinephrine, and cortisol. Cortisol is secreted from the adrenal glands in response to stressor-induced activation of the hypothalamic-pituitary-adrenal axis. For assessment of environmental noise and stress, repeated sampling in blood, saliva, or urine is necessary to evaluate the association between environmental noise exposure and protracted changes in cortisol. Controlling for the many variables that influence the secretion of cortisol at discrete sampling intervals is challenging. Studies suggest that systemically produced cortisol integrates and remains in hair as it grows, providing a measure that integrates a cortisol response over a longer period, circumventing several limitations associated with multiple sampling. Robust evidence supports the integration of cortisol into hair, yet recent studies call into question the notion that cortisol is retained with growth. The current paper discusses the strengths and limitations of hair cortisol analysis with an emphasis on its utility as a measure of chronic stress in environmental noise studies.

Impact of aeroplane noise on mental and physical health: a quasi-experimental analysis

OBJECTIVES

Historically, departures at New York City's LaGuardia airport flew over a large sports complex within a park. During the US Open tennis games, flights were diverted to fly over a heavily populated foreign-born neighbourhood for roughly 2 weeks out of the year so that the tennis match was not disturbed (the 'TNNIS' departure). In 2012, the use of the TNNIS departure became year-round to better optimise flight patterns around the metropolitan area.

METHODS

We exploited exogenously induced spatial and temporal variation in flight patterns to examine difference-in-difference effects of this new exposure to aircraft noise on the health of individual residents in the community relative to individuals residing within a demographically similar community that was not impacted. We used individual-level Medicaid records, focusing on conditions associated with noise: sleep disturbance, psychological stress, mental illness, substance use, and cardiovascular disease.

RESULTS

We found that increased exposure to aeroplane noise was associated with a significant increase in insomnia across all age groups, but particularly in children ages 5-17 (OR=1.64, 95% CI=1.12 to 2.39). Cardiovascular disease increased significantly both among 18-44-year-old (OR=1.45, 95% CI=1.41 to 1.49) and 45-64-year-old Medicaid recipients (OR=1.15, 95% CI=1.07 to 1.25). Substance use and mental health-related emergency department visits also increased. For ages 5-17,rate ratio (RR) was 4.11 (95% CI=3.28 to 5.16); for ages 18-44, RR was 2.46 (95% CI=2.20 to 2.76); and for ages 45-64, RR was 1.48 (95% CI=1.31 to 1.67).

CONCLUSION

We find that increased exposure to aeroplane noise was associated with an increase in diagnosis of cardiovascular disease, substance use/mental health emergencies and insomnia among local residents.

Non-auditory effects of industrial chronic noise exposure on workers; change in salivary cortisol pattern

Background

Noise has different auditory and non-auditory effects on human. In noisy environments, noise as a non-specific stressor can activates the hypothalamic-pituitary-adrenal axis (HPA, cortisol). The aim of this study was to evaluate the effect of chronic exposure to noise on salivary cortisol on industrial workers.

Methods

This cross-sectional study had a case/control design. 136 male workers (68 workers were exposed to chronic industrial noise, and 68 other workers were exposed to background noise) voluntarily enrolled in the study. The equivalent noise level was measured at workstations and salivary cortisol for both case and control groups was measured at the beginning (6 AM) and also at the end of work shift (4 PM). The amount of change in the average of the values of the two groups were compared with each other.

Results

The measured Leq_8h (equivalent continuous sound level) in case and control groups were 87.43 dB-A and 67.6 dB-A, respectively. Comparison of salivary cortisol levels change in groups shows a significant differences in control groups for salivary cortisol in the morning and in the evening samples (p < 0.05); but not in the case group (p = 0.052). Also, comparison of salivary cortisol levels changes with noise exposure experience in the case subgroups revealed no significant difference (p > 0.05).

Conclusion

This study showed that chronic exposure to industrial noise can lead to a change in pattern of salivary cortisol secretion especially in the evening (at the end of the work shift), in a way that instead of its normal decrease, an increase happened.

Weighing and modelling factors influencing serum cortisol and melatonin concentration among workers that are exposed to various sound pressure levels using neural network algorithm: An empirical study

BACKGROUND

Noise is one of the most common harmful agents in the workplace. Exposure to excessive noise can lead to complications such as cardiovascular disorders, disturbance of body hormones' rhythm and hearing loss. This study aimed at weighing and modelling factors influencing serum cortisol and melatonin concentrations of workers that are exposed to various sound pressure levels using neural network algorithm.

METHODOLOGY

A case-control design was adopted in the current research. The required data were collected from 75 industrial and mining firm staff members. They were assigned to three groups with equal sample sizes (25 workers). In developing the conceptual model in regard to variables that may affect workers' serum cortisol and melatonin concentration, SPL, age, weight, and height were included. The influence of SPL on serum cortisol concentration as assessed in the three shifts. Moreover, radioimmunoassay (RIA) was utilized to assess serum cortisol and melatonin concentrations. Neural network algorithm was subsequently exploited to weigh and model predictor factors. IBM SPSS Modeler 18.0 was the software program used for data analysis.

RESULTS

The average cortisol concentration values for administrative, condensing, and pelletizing units respectively were 10.24 ± 2.35, 12.15 ± 3.46, and 14.91 ± 4.16μ g d l . On the other hand, the average melatonin concentration values for administrative, condensing, and pelletizing units respectively were 37 ± 12.52, 34 ± 13.15, and 27 ± 9.54μ g d l . According to the results of the developed model for cortisol, SPL3 (32%) and age (5%) respectively had the highest and lowest impact. On the other hand, considering the model developed for melatonin, height (27%) and SPL1 (10%) were the most and least influential factors in that order. The accuracy rates of the model were also found to be 95% for cortisol and 97% for melatonin.

CONCLUSION

Comparing cortisol concentrations during various shifts revealed a significant reduction (from the beginning to the end of the shift) in all the three groups. Further, the rise of SPL would result in higher secretion of cortisol. Moreover, in all the three groups, the average serum melatonin concentration went up from the beginning to the middle of the shift and then declined to the end of the shift. Considering the accuracy rates of the models developed to predict hormones, neural network algorithm is a suitable and powerful tool for weighing and modelling factors influencing serum cortisol and melatonin concentrations.

The Effect of Noise Exposure on Cognitive Performance and Brain Activity Patterns

BACKGROUND:

It seems qualitative measurements of subjective reactions are not appropriate indicators to assess the effect of noise on cognitive performance.

AIM:

In this study, quantitative and combined indicators were applied to study the effect of noise on cognitive performance.

MATERIAL AND METHODS:

A total of 54 young subjects were included in this experimental study. The participants’ mental workload and attention were evaluated under different levels of noise exposure including, background noise, 75, 85 and 95 dBA noise levels. The study subject’s EEG signals were recorded for 10 minutes while they were performing the IVA test. The EEG signals were used to estimate the relative power of their brain frequency bands.

RESULTS:

Results revealed that mental workload and visual/auditory attention is significantly reduced when the participants are exposed to noise at 95 dBA level (P < 0.05). Results also showed that with the rise in noise levels, the relative power of the Alpha band increases while the relative power of the Beta band decreases as compared to background noise. The most prominent change in the relative power of the Alpha and Beta bands occurs in the occipital and frontal regions of the brain respectively.

CONCLUSION:

The application of new indicators, including brain signal analysis and power spectral density analysis, is strongly recommended in the assessment of cognitive performance during noise exposure. Further studies are suggested regarding the effects of other psychoacoustic parameters such as tonality, noise pitch (treble or bass) at extended exposure levels.

The effect of occupational noise exposure on systolic blood pressure, diastolic blood pressure and salivary cortisol level among automotive assembly workers

Introduction. Both auditory and non-auditory health can be affected by exposure to occupational noise. The aim of this study was to evaluate the association of high occupational noise (at three levels) with systolic blood pressure (SBP), diastolic blood pressure (DBP) and salivary cortisol concentration in an automotive factory. Methods. This study was carried out on 78 male workers from a factory who worked in the warehouse unit (control group: 60-70 dB(A)) and assembly units (two test groups: 75-85 and 85-95 dB(A)). Data were collected through questionnaires and measurement of SBP, DBP, saliva cortisol concentration and body mass index (BMI), prior to and post occupational noise exposure. The measurements were performed twice/day and repeated after 10 days. Results. For each occupational noise level group, there was no significant association between cortisol level with age and BMI. The SBP and DBP in all groups increased significantly. Also, the average cortisol levels were similar in different groups before noise exposure, but were statistically different after occupational noise exposure. Conclusions. High occupational noise exposure increases the cortisol level and blood pressure, which are the major risk factors of cardiovascular disease.

Involvement of prolactin in newborn infant irritability following maternal perinatal anxiety symptoms

BACKGROUND

Newborn irritability could be an unique and special status and/or adverse neurobehavioral outcomes which was independent of serious disease. To determine whether maternal perinatal anxiety symptoms was associated with newborn irritability, and whether the alteration of serum prolactin in newborns were involved in newborn irritability.

METHODS

205 pregnant women were recruited: normal group (n = 100), and anxiety group (n = 105), which was randomly divided to Newborn Behavioral Observations (NBO)+anxiety group(n = 65) and control+anxiety group(n = 40). Newborn Irritability was assessed by Neonatal Behavioral Assessment Scale(NBAS). Serum prolactin, cortisol and 5-HT in mothers and infants were measured.

RESULTS

1. The scores of irritability items in the newborns of anxiety group were higher than that of the normal group (p < 0.05). 2. Lower serum PRL, 5-HT and higher serum cortisol were found in the newborns of anxiety group compared with that of the control group both postpartum 2d and 15 (p < 0.05). 3. The level of serum PRL in newborn infants were significantly and negatively correlated to the scores of irritability items (p < 0.05). 4. After 7 rounds of NBO interventions, the anxiety scores of mothers and the scores of irritability items of newborns in the NBO intervention group were all lower than those of the control group (p < 0.05) .

LIMITATIONS

In future experiments, we should explore the effect of PRL in the breast milk on newborn infant serum PRL.

CONCLUSIONS

Prolactin could be a potential mediator in newborn irritability following maternal perinatal anxiety symptoms.

The Effect of Occupational Noise Exposure on Serum Cortisol Concentration of Night-shift Industrial Workers: A Field Study

Background

In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift.

Methods

This case–control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with α = 0.05.

Results

The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62).

Conclusion

Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.

Motivated Shield From Chronic Noise Environment: Moderation of the Relationship Between Noise Sensitivity and Work Wellbeing by Need for Closure

Several studies have underlined how chronic exposure to environmental noise may have negative effects on performance, wellbeing, and social relations. The present study (N = 90 employees of a motor factory who are chronically exposed to environmental noise) investigated whether the negative effects of chronic exposure of noise-sensitive individuals to noise in the workplace may be moderated by the need for cognitive closure (i.e., an epistemic tendency to reduce uncertainty; NFCC, Kruglanski, 2004). As NFCC has been shown to enhance protection of the focal goal by reducing interference (Kossowska, 2007; Pica et al., 2013), we hypothesized that people with high NFCC should be able to manage the interference coming from environmental noise and concentrate on their tasks more than their low-NFCC counterparts. The results confirm that the negative effects of noise sensitivity on job satisfaction, state anxiety, and turnover intent were higher among low (vs. high)-NFCC individuals.

Questionnaire-based algorithm for assessing occupational noise exposure of construction workers

Objectives

Occupational noise exposure is a major cause of hearing loss worldwide. In order to inform preventative strategies, we need to further understand at a population level which workers are most at risk.

Methods

We have developed a new questionnaire-based algorithm that evaluates an individual worker’s noise exposure. The questionnaire and supporting algorithms are embedded into the existing software platform, OccIDEAS. Based on the tasks performed by a worker during their most recent working shift and using a library of task-based noise exposure levels, OccIDEAS estimates whether a worker has exceeded the full-shift workplace noise exposure limit (LAeq,8h≥85 dBA). We evaluated the validity of the system in a sample of 100 construction workers. Each worker wore a dosimeter for a full working shift and was then interviewed using the OccIDEAS software.

Results

The area under the receiver operating characteristic curve was 0.81 (95% CI 0.72 to 0.90) indicating that the ability of OccIDEAS to identify construction workers with an LAeq,8h≥85 dBA was excellent.

Conclusion

This validated noise questionnaire may be useful in epidemiological studies and for workplace health and safety applications.

A survey of the prevalence of fatigue, its precursors and individual coping mechanisms among U.S. manufacturing workers

Advanced manufacturing has resulted in significant changes on the shop-floor, influencing work demands and the working environment. The corresponding safety-related effects, including fatigue, have not been captured on an industry-wide scale. This paper presents results of a survey of U.S. manufacturing workers for the: prevalence of fatigue, its root causes and significant factors, and adopted individual fatigue coping methods. The responses from 451 manufacturing employees were analyzed using descriptive data analysis, bivariate analysis and Market Basket Analysis. 57.9% of respondents indicated that they were somewhat fatigued during the past week. They reported the ankles/feet, lower back and eyes were frequently affected body parts and a lack of sleep, work stress and shift schedule were top selected root causes for fatigue. In order to respond to fatigue when it is present, respondents reported coping by drinking caffeinated drinks, stretching/doing exercises and talking with coworkers. Frequent combinations of fatigue causes and individual coping methods were identified. These results may inform the design of fatigue monitoring and mitigation strategies and future research related to fatigue development.

Sound as a supportive design intervention for improving health care experience in the clinical ecosystem: A qualitative study

PURPOSE

Most prior hospital noise research usually deals with sound in its noise facet and is based merely on sound level abatement, rather than as an informative or orientational element. This paper stimulates scientific research into the effect of sound interventions on physical and mental health care in the clinical environment.

METHODS

Data sources comprised relevant World Health Organization guidelines and the results of a literature search of ISI Web of Science, ProQuest Central, MEDLINE, PubMed, Scopus, JSTOR and Google Scholar.

RESULTS

Noise induces stress and impedes the recovery process. Pleasant natural sound intervention which includes singing birds, gentle wind and ocean waves, revealed benefits that contribute to perceived restoration of attention and stress recovery in patients and staff.

CONCLUSIONS

Clinicians should consider pleasant natural sounds perception as a low-risk non-pharmacological and unobtrusive intervention that should be implemented in their routine care for speedier recovery of patients undergoing medical procedures.

Gender differences in use of hearing protection devices among farm operators

Purpose:

Although farm operators have frequent exposure to hazardous noise and high rates of noise-induced hearing loss, they have low use of hearing protection devices (HPDs). Women represent about one-third of farm operators, and their numbers are climbing. However, among published studies examining use of HPDs in this worker group, none have examined gender-related differences. The purpose of this study was to examine gender-related differences in use of hearing protection and related predictors among farm operators.

Materials and Methods:

Data previously collected at farm shows and by telephone were analyzed using t-tests and generalized linear model with zero inflated negative binomial (ZINB) distribution.

Findings:

The difference in rate of hearing protector use between men and women farm operators was not significant. There was no difference between men and women in most hearing protector-related attitudes and beliefs.

Conclusion:

Although men and women farm operators had similar rates of use of hearing protectors when working in high-noise environments, attitudes about HPD use differed. Specifically, interpersonal role modeling was a predictor of HPD use among women, but not for men. This difference suggests that while farm operators of both genders may benefit from interventions designed to reduce barriers to HPD use (e.g., difficulty communicating with co-workers and hearing warning sounds), farm women have unique needs in relation to cognitive-perceptual factors that predict HPD use. Women farm operators may lack role models for use of HPDs (e.g., in peers and advertising), contributing to their less frequent use of protection.

Time to wake up: reactive countermeasures to sleep inertia

Sleep inertia is the period of impaired performance and grogginess experienced after waking. This period of impairment is of concern to workers who are on-call, or nap during work hours, and need to perform safety-critical tasks soon after waking. While several studies have investigated the best sleep timing and length to minimise sleep inertia effects, few have focused on countermeasures -especially those that can be implemented after waking (i.e. reactive countermeasures). This structured review summarises current literature on reactive countermeasures to sleep inertia such as caffeine, light, and temperature and discusses evidence for the effectiveness and operational viability of each approach. Current literature does not provide a convincing evidence-base for a reactive countermeasure. Caffeine is perhaps the best option, although it is most effective when administered prior to sleep and is therefore not strictly reactive. Investigations into light and temperature have found promising results for improving subjective alertness; further research is needed to determine whether these countermeasures can also attenuate performance impairment. Future research in this area would benefit from study design features highlighted in this review. In the meantime, it is recommended that proactive sleep inertia countermeasures are used, and that safety-critical tasks are avoided immediately after waking.

The influence of occupational heat exposure on cognitive performance and blood level of stress hormones: a field study report

INTRODUCTION

This article aimed to investigate the effect of heat stress on cognitive performance and the blood concentration of stress hormones among workers of a foundry plant.

METHODS

Seventy workers within the exposed (35 people) and unexposed (35 people) groups were studied. The wet bulb globe temperature (WBGT) index was measured for heat stress assessment. The cognitive performance tests were conducted using the Stroop color word test (SCWT) before and during working hours. For the assessment of the serum level of cortisol and the plasma level of adrenaline and noradrenaline, blood samples were taken during working hours from both groups.

RESULTS

Only for SCWT III was there a significant relationship between heat stress and test duration, error rate and reaction time. The laboratory test results revealed significantly higher concentrations of cortisol, adrenaline and noradrenaline in the exposed subjects than in the unexposed group. There existed a positive correlation between cortisol, adrenaline, noradrenaline and WBGT index and also test duration and reaction time of SCWT III, and number of errors of SCWT I, SCWT II and SCWT III during work.

CONCLUSION

Heat stress can lead to an increase in the blood level of stress hormones, resulting in cognitive performance impairment.

Exploring the effect of sound and music on health in hospital settings: A narrative review

BACKGROUND

Sound in hospital space has traditionally been considered in negative terms as both intrusive and unwanted, and based mainly on sound levels. However, sound level is only one aspect of the soundscape. There is strong evidence that exploring the positive aspect of sound in a hospital context can evoke positive feelings in both patients and nurses. Music psychology studies have also shown that music intervention in health care can have a positive effect on patient's emotions and recuperating processes. In this way, hospital spaces have the potential to reduce anxiety and stress, and make patients feel comfortable and secure. This paper describes a review of the literature exploring sound perception and its effect on health care.

DATA SOURCES AND REVIEW METHODS

This review sorted the literature and main issues into themes concerning sound in health care spaces; sound, stress and health; positive soundscape; psychological perspective of music and emotion; music as a complementary medicine for improving health care; contradicting arguments concerning the use of music in health care; and implications for clinical practice. Using Web of Science, PubMed, Scopus, ProQuest Central, MEDLINE, and Google, a literature search on sound levels, sound sources and the impression of a soundscape was conducted. The review focused on the role and use of music on health care in clinical environments. In addition, other pertinent related materials in shaping the understanding of the field were retrieved, scanned and added into this review.

RESULTS

The result indicated that not all noises give a negative impression within healthcare soundscapes. Listening to soothing music was shown to reduce stress, blood pressure and post-operative trauma when compared to silence. Much of the sound conveys meaningful information that is positive for both patients and nurses, in terms of soft wind, bird twitter, and ocean sounds.

CONCLUSIONS

Music perception was demonstrated to bring about positive change in patient-reported outcomes such as eliciting positive emotion, and decreasing the levels of stressful conditions. Whilst sound holds both negative and positive aspects of the hospital ecosystem and may be stressful, it also possesses a soothing quality that induces positive feelings in patients. Conceptualizing the nature of sound in the hospital context as a soundscape, rather than merely noise can permit a subtler and socially useful understanding of the role of sound and music in the hospital setting, thereby creating a means for improving the hospital experience for patients and nurses.

Influence of traffic-related noise and air pollution on self-reported fatigue

A growing body of evidence suggests that exposure to environmental pollutions is related to health problems. It is, however, questionable whether this condition affects working performance in occupational settings. The aim of this study is to determine the predictive value of age as well as traffic related air and noise pollutions for fatigue. 246 traffic officers participated in this study. Air pollution data were obtained from the local Air Quality Control Company. A sound level meter was used for measuring ambient noise. Fatigue was evaluated by the MFI-20 questionnaire. The general and physical scales showed the highest, while the reduced activity scale showed the lowest level of fatigue. Age had an independent direct effect on reduced activity and physical fatigue. The average of daytime equivalent noise level was between 71.63 and 88.51 dB(A). In the case of high noise exposure, older officers feel more fatigue than younger ones. Exposure to PM10 and O3 resulted in general and physical fatigue. Complex Interactions between SO2, CO and NO2 were found. Exposure to noise and some components of air pollution, especially O3 and PM10, increases fatigue. The authorities should adopt and rigorously implement environmental protection policies in order to protect people.

Intermittent Noise Induces Physiological Stress in a Coastal Marine Fish

Anthropogenic noise in the ocean has increased substantially in recent decades, and motorized vessels produce what is likely the most common form of underwater noise pollution. Noise has the potential to induce physiological stress in marine fishes, which may have negative ecological consequences. In this study, physiological effects of increased noise (playback of boat noise recorded in the field) on a coastal marine fish (the giant kelpfish, Heterostichus rostratus) were investigated by measuring the stress responses (cortisol concentration) of fish to increased noise of various temporal dynamics and noise levels. Giant kelpfish exhibited acute stress responses when exposed to intermittent noise, but not to continuous noise or control conditions (playback of recorded natural ambient sound). These results suggest that variability in the acoustic environment may be more important than the period of noise exposure for inducing stress in a marine fish, and provide information regarding noise levels at which physiological responses occur.

Protocol of a randomized controlled trial of hearing protection interventions for farm operators

Background

Hearing loss and tinnitus are prevalent in America, and noise-induced hearing loss is a leading cause of hearing loss. Noise-induced hearing loss has negative impact on quality of life, physical and emotional functioning, social life, and employment. In addition, noise-induced hearing loss results in heavy social and economic burdens on families and communities from all ethnic and socioeconomic groups. Farmers are a group that is particularly high risk for noise-induced hearing loss, and is underserved by programs designed to limit that risk. They are among the most noise-exposed group of workers, and experience the second highest prevalence of noise-induced hearing loss among all occupational categories. In agriculture, 1.5 million workers (43.3%) report exposure to hazardous noise. Although use of hearing protection devices (HPDs) would protect them from noise-induced hearing loss, use among farmers is low.

Methods/Design

The purpose of this project is to compare the effectiveness of several approaches to influencing hearing protector use. Approaches include: a) an interactive, predictors-based intervention delivered via the Internet; b) a static informational web site; and c) a mailed sampler of hearing protectors. The goals are to further develop an intervention to promote farmers’ use of HPDs, and compare the effectiveness of the interventions delivered in various combinations. Participants will include 701 farmers. Sites will be affiliates of a major farmer organization. Data will be collected at baseline, 6, and 12 months. A random intercept mixed model will be used to explore the fixed effects of the three NIHL prevention interventions over time while adjusting for age and gender. This project will involve a partnership between the University of Michigan and a major farmer organization to accomplish project aims.

Discussion

Results of this study will be used to inform future research-to-practice studies to increase hearing protector use. Increased use of hearing protectors is expected to reduce rates of noise-induced hearing loss and other negative effects of high noise exposure, and improve quality of life in this high-risk and underserved group.

Trial registration

Clinicaltrials.gov NCT01454895 Registered 14 October, 2011.

Effect of Noise Intensity and Illumination Intensity on Visual Performance

The results of Experiment 1 indicated that noise and illumination intensity have a significant effect on character identification performance, which was better at 30 dBA than at 60 and 90 dBA, and better at 500 and 800 lux than at 200 lux. However, the interaction of noise and illumination intensity did not significantly affect visual performance. The results of Experiment 2 indicated that noise and illumination intensity also had a significant effect on reading comprehension performance, which was better at 30 dBA than at 60 and 90 dBA, and better at 500 lux than at 200 and 800 lux. Furthermore, reading comprehension performance was better at 500 lux lighting and 30 dBA noise than with 800 lux and 90 dBA. High noise intensity impaired visual performance, and visual performance at normal illumination intensity was better than at other illumination intensities. The interaction of noise and illumination had a significant effect on reading comprehension. These results indicate that noise intensity lower than 30 dBA and illumination intensity approximately 500 lux might be the optimal conditions for visual work.

Recent and long-term occupational noise exposure and salivary cortisol level

Environmental and occupational noise exposure have been related to increased risk of cardiovascular disease, hypothetically mediated by stress-activation of the hypothalamic-pituitary-adrenal (HPA) axis. The objective of this study was to investigate the relation between recent and long-term occupational noise exposure and cortisol level measured off work to assess a possible sustained HPA-axis effect. We included 501 industrial, finance, and service workers who were followed for 24h during work, leisure, and sleep. Ambient occupational noise exposure levels were recorded every 5s by personal dosimeters and we calculated the full-shift LAEq value and estimated duration and cumulative exposure based on their work histories since 1980. For 332 workers who kept a log-book on the use of hearing protection devices (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the noise level at the ear. Salivary cortisol concentration was measured at 20.00 h, the following day at awakening, and 30 min after awakening on average 5, 14 and 14.5h after finishing work. The mean ambient noise exposure level was 79.9 dB(A) [range: 55.0-98.9] and the mean estimated level at the ear 77.7 dB(A) [range: 55.0-94.2]. In linear and mixed regression models that adjusted for age, sex, current smoking, heavy alcohol consumption, personal income, BMI, leisure-time noise exposure level, time since occupational noise exposure ceased, awakening time, and time of saliva sampling, we observed no statistically significant exposure response relation between recent, or long-term ambient occupational noise exposure level and any cortisol parameter off work. This was neither the case for recent noise level at the ear. To conclude, neither recent nor long-term occupational noise exposure levels were associated with increased cortisol level off work. Thus, our results do not indicate that a sustained activation of the HPA axis, as measured by cortisol, is involved in the causal pathway between occupational noise exposure and cardiovascular disease.

An exploratory spatial analysis to assess the relationship between deprivation, noise and infant mortality: an ecological study

BACKGROUND

Few studies have explored how noise might contribute to social health inequalities, and even fewer have considered infant mortality or its risk factors as the health event of interest.In this paper, we investigate the impact of neighbourhood characteristics - both socio-economic status and ambient noise levels - on the spatial distribution of infant mortality in the Lyon metropolitan area, in France.

METHODS

All infant deaths (n = 715) occurring between 2000 and 2009 were geocoded at census block level. Each census block was assigned multi-component socio-economic characteristics and Lden levels, which measure exposure to noise. Using a spatial-scan statistic, we examined whether there were significant clusters of high risk of infant mortality according to neighbourhood characteristics.

RESULTS

Our results highlight the fact that infant mortality is non-randomly distributed spatially, with clusters of high risk in the south-east of the Lyon metropolitan area (RR = 1.44; p = 0.09). After adjustments for socio-economic characteristics and noise levels, this cluster disappears or shifts according to in line with different scenarios, suggesting that noise and socio-economic characteristics can partially explain the spatial distribution of infant mortality.

CONCLUSION

Our findings show that noise does have an impact on the spatial distribution of mortality after adjustments for socio-economic characteristics. A link between noise and infant mortality seems plausible in view of the three hypothetical, non-exclusive, pathways we propose in our conceptual framework: (i) a psychological pathway, (ii) a physiological disruption process and (iii) an unhealthy behaviours pathway. The lack of studies makes it is difficult to compare our findings with others. They require further research for confirmation and interpretation.

Mass transit ridership and self-reported hearing health in an urban population

Information on prevalence and risk factors associated with self-reported hearing health among mass transit riders is extremely limited, even though evidence suggests mass transit may be a source of excessive exposure to noise. Data on mass transit ridership were collected from 756 study participants using a self-administered questionnaire. Hearing health was measured using two symptom items (tinnitus and temporary audiometric threshold shift), two subjective measures (self-rated hearing and hearing ability), and two medical-related questions (hearing testing and physician-diagnosed hearing loss). In logistic regression analyses that controlled for possible confounders, including demographic variables, occupational noise exposure, nonoccupational noise exposure (including MP3 player use) and use of hearing protection, frequent and lengthy mass transit (all forms) ridership (1,100 min or more per week vs. 350 min or less per week) was the strongest predictor of temporary threshold shift symptoms. Noise abatement strategies, such as engineering controls, and the promotion of hearing protection use should be encouraged to reduce the risk of adverse impacts on the hearing health of mass transit users.

O ruído da unidade de terapia intensiva neonatal após a implementação de programa educativo

O estudo verificou os níveis de pressão sonora no interior das incubadoras e na Unidade de Terapia Intensiva Neonatal, seis meses após a implementação de um programa educativo. Estudo quantitativo descritivo, realizado na Unidade de Terapia Intensiva Neonatal e no interior das incubadoras de um hospital. Foram registrados 151 horas e 30 minutos de níveis de pressão sonora da Unidade de Terapia Intensiva Neonatal e do interior da incubadora, em janeiro de 2009 e 2010. O maior e o menor Leq médios, antes do programa educativo na Unidade de Terapia Intensiva Neonatal foram 71,0 dBA e 59,0 dBA, respectivamente. Após a intervenção, registraram-se na Unidade de Terapia Intensiva Neonatal, Leq médio entre 80,4 e 52,6 dBA. Na incubadora, valores variaram de 79,2 a 40,0 dBA para 79,1 a 45,4dBA após a intervenção, permanecendo acima dos valores recomendados. Constatou-se que não houve redução do nível de pressão sonora após a intervenção. Sugerem-se estratégias para sensibilização da equipe, elaboração de guideline, mudanças arquitetônicas, e renovação e/ou manutenção preventiva de equipamentos.

The impact of prison conditions on staff well-being

Prison conditions have been at the center of long-standing debates among corrections scholars. Interestingly, this debate has focused on inmates alone while paying little attention to the potential impact of prison conditions on staff. Addressing this limitation, the study draws on survey data collected from a stratified random sample of prison staff working at all federal prisons in 2007 to examine the impact of prison conditions on staff well-being (substance use, psychological symptomatology, physical duress, and sick leave use). Mixed-level models show that harsh physical conditions correspond to significant problems for staff on all outcomes measured (individual-level impacts). The data also show that prison-level aggregations of harsher conditions correspond to significant deterioration in staff physical and psychological symptomatology above and beyond individual-level effects.

Sleep habits, alertness, cortisol levels, and cardiac autonomic activity in short-distance bus drivers: differences between morning and afternoon shifts

OBJECTIVE

To evaluate sleep, alertness, salivary cortisol levels, and autonomic activity in the afternoon and morning shifts of a sample of short-distance bus drivers.

METHODS

A sample of 47 bus drivers was evaluated. Data regarding subjects and working characteristics, alertness (psychomotor vigilance task), sleep habits (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Actigraphy), endocrine stress response (salivary cortisol), and autonomic activity (heart-rate variability) were collected.

RESULTS

Sleep restriction was highly prevalent. Drivers in the morning shift slept 1 hour less than those in the afternoon shift, showed lower reaction time performance, a flattening of cortisol morning-evening difference, and higher overweight prevalence.

CONCLUSIONS

The differences found between morning and afternoon shifts point out to the need of the implementation of educational strategies to compensate the sleep loss associated with an early work schedule.

Nível de ruído em sala de parto

Teve como objetivo identificar níveis de pressão sonora em salas de parto e fontes de ruído. Estudo quantitativo, descritivo, exploratório. Coleta de dados ocorreu de outubro de 2008 a julho de 2009. Utilizou-se um dosímetro para registrar os níveis de pressão sonora e a observação não-estruturada para identificar fontes geradoras. Realizaram-se 2.928 minutos de registros do ruído e observação de fontes. Valores de nível de pressão sonora equivalente (Leq) foram calculados pelo software Quest Suit. Identificou-se Leq médio de 69,6 dBA (± 3,69) em partos normais e 65,4 dBA (± 2,28) em cesáreas. Fonte mais frequente de ruído foi diálogo entre profissionais. Os níveis de pressão sonora estão acima dos recomendados pelos órgãos competentes e a principal fonte de ruído está relacionada ao comportamento dos profissionais. Faz-se necessário implementar programas educativos a fim de amenizar o ruído e melhorar a assistência ao neonato e família e as condições de trabalho.

Influence of indoor-cat group size and dominance rank on urinary cortisol levels

Domestic cats (Felis silvestris catus) are often housed indoors both singly and in groups. However, there is a lack of studies dealing with cat-cat relationships, group composition and effects of environmental parameters on the well-being of privately-owned cats. One way to index the effects of stressful situations is to measure glucocorticoid levels, as glucocorticoids are released from the adrenal cortex in response to stress-induced activation of the hypothalamic-pituitary-adrenal axis. Therefore, we investigated the influence of single and group housing on basal urinary cortisol levels of indoor-only domestic cats in private households, taking into account dominance status and environmental parameters. Urine samples were collected non-invasively by owners from six single-housed cats and six alpha-omega animal pairs of multi-cat households. Dominance status in group-housed cats was determined by competition test series. Additionally, we compared cortisol levels of privately-owned cats with those of shelter cats. Results showed that basal urinary cortisol levels of cats in private households are neither influenced by housing style (single cat vs multi cat) nor by individuals' dominance status. Correlations indicated a positive influence of human density, number of persons per household, and number of m2 available to cats on basal urinary cortisol levels, whereas cat-related parameters such as number of cats per household, number of m2 per cat, and number of persons per cat, did not have any significant influence on basal urinary cortisol levels. A comparison of basal urinary cortisol levels of privately-owned and shelter cats revealed no influence of location (private household, shelter) and group type (single, group [dominant or subordinate]) on basal urinary cortisol levels. This study is the first to investigate basal urinary cortisol levels of domestic cats in private households and an animal shelter considering housing style, dominance status, and environmental parameters.

Impact of stressors in a natural context on release of cortisol in healthy adult humans: a meta-analysis

Increased hypothalamic-pituitary-adrenal (HPA) activation, culminating in elevated circulating cortisol levels is a fundamental response to stressors. In animals, this neuroendocrine change is highly reliable and marked (approximately 5-10-fold elevations), whereas in humans, the increase of cortisol release is less pronounced, and even some potent life-threatening events (anticipation of surgery) only elicit modest cortisol increases. Meta-analysis of factors that influenced the increase of cortisol release in a laboratory context pointed to the importance of social evaluative threats and stressor controllability in accounting for the cortisol rise. The present meta-analysis, covering the period from 1978 through March 2007, was undertaken to identify the factors most closely aligned with cortisol increases in natural settings. It appeared that stressor chronicity was fundamental in predicting cortisol changes; however, this variable is often confounded by the stressor type, the stressor's controllability, as well as contextual factors, making it difficult to disentangle their relative contributions to the cortisol response. Moreover, several experiential factors (e.g. previous stressor experiences) may influence the cortisol response to ongoing stressors, but these are not readily deduced through a meta-analysis. Nevertheless, there are ample data suggesting that stressful events, through their actions on cortisol levels and reactivity, may influence psychological and physical pathology.

Environmental noise-exposed workers: Event-related potentials, neuropsychological and mood assessment

Prolonged environmental noise exposure can induce pathogenic effects on various physical and psychosocial responses. The first aim of this study was to investigate whether long-term occupational noise exposure could affect neurophysiological, neuropsychological and emotional statuses, with particular respect to attention and working memory. The second aim was to evaluate the effects on the tactile P300 of a specific stressor (background traffic noise) vs a non-specific stress inductor (Stroop test). The comparison between a group of noise-exposed workers (traffic police officers), and a control group (office employees) did not show marked differences in cognitive and emotional profiles. The amplitude of the baseline cognitive potential (P300), recorded during a tactile (electric) discrimination task, resulted higher in noise-exposed workers than in controls, and this enhancement was associated with a lower level of trait anxiety and better mood profiles. Moreover, we found a wider P300 amplitude reduction in traffic police officers than in controls, under noisy conditions due to traffic. The effect of the Stroop test as a stress inductor was negligible and similar in the two groups. The wider amplitude of the non-auditory P300 in traffic police officers in the baseline condition could be a sign of cross-modal cerebral plasticity enhancing attentive processes in the 'stress-free' sensory channel. In addition, noise-exposed workers presented a higher cerebral sensitivity to stress selectively when they were exposed to the habitual environmental stressor.

Saliva cortisol--a new approach in noise research to study stress effects

Several studies have indicated an association between noise exposure and cardiovascular disease. A noise-induced release of stress hormones has been considered to be a biological pathway of importance in this respect. The described method is of special interest since concentration of cortisol in saliva reflects the concentration of free cortisol in serum and repeated saliva samples can easily be collected. Our objective is to overview the use of saliva cortisol to measure stress in relation to noise as a tool for research on noise-related cardiovascular risk. Previous studies of saliva cortisol in relation to noise exposure are reviewed. In summary, repeated assessments of saliva cortisol seems to be a feasible method to apply in field studies in noise research.

Physiological stress response to video-game playing: the contribution of built-in music

Recent studies on video game playing have uncovered a wide range of measurable physiological effects on the organism, such as increases in cardiovascular activity and breathing responses. However, the exact source of these effects remains unclear. Given the well-known effects of sound on physiological activity, especially those of noise and of music, and on the secretion of the stress hormone cortisol in particular, we hypothesized that music may be a major source of stress during video game playing. We thus examined the effect of built-in music on cortisol secretion as a consequence of video game playing. Players were assigned quasi-randomly to either a Music or a Silence condition. Four saliva samples were taken, that is, after practice (T1), immediately after having played for 10 minutes (T2), 15 minutes after the end of the experiment (T3), and 30 minutes after the end of the experiment (T4). The results show that the Music group had significantly higher cortisol levels at T3, that is, when cortisol levels are assumed to reflect the stress induced by the game. These findings suggest for the first time that the auditory input contributes significantly to the stress response found during video game playing.

Arrest in ciliated cell expansion on the bronchial lining of adult rats caused by chronic exposure to industrial noise

Workers chronically exposed to high-intensity/low-frequency noise at textile plants show increased frequency of respiratory infections. This phenomenon prompted the herein investigation on the cytology of the bronchial epithelium of Wistar rats submitted to textile noise. Workplace noise from a cotton-mill room of a textile factory was recorded and reproduced in a sound-insulated animal room. The Wistar rats were submitted to a weekly schedule of noise treatment that was similar to that of the textile workers (8h/day, 5 days/week). Scanning electron microscopy (SEM) was used to compare the fine morphology of the inner surface of the bronchi in noise-exposed and control rats. SEM quantitative cytology revealed that exposure to noise for 5-7 months caused inhibition in the natural expansion of the area occupied by ciliated cells on the bronchial epithelium as adult rats grow older. This difference between noise-exposed and age-matched control rats was statistically significant (P<0.05) and documents that the cytology of the rat bronchial epithelium is mildly altered by noise exposure. The decrease in the area of bronchial cilia may impair the mucociliar clearance of the respiratory airways and, thus, increase vulnerability to respiratory infection.

Long-term exposure to occupational noise alters the cortical organization of sound processing

OBJECTIVE

Long-term exposure to noise may cause an altered hemispheric lateralization of speech processing even in silent conditions. We examined whether this lateralization shift is speech specific or occurs also for other sounds.

METHODS

Brain responses from 10 healthy noise-exposed workers (>5 years) and 10 matched controls were recorded with a 32-channel electroencephalogram in two conditions, one including standard and deviant speech sounds, the other non-speech sounds, with novel sounds in both.

RESULTS

The deviant-sound elicited mismatch negativity (MMN) was larger to non-speech than speech sounds in control subjects, while it did not differ between the sound types in the noise-exposed subjects. Moreover, the MMN to speech sounds was lateralized to the right hemisphere in exposed workers, while it was left-hemisphere predominant in control subjects. No group topography difference was found for non-speech sounds. The deviant sounds that were close in formant space to the standards elicited a longer MMN latency in both speech and non-speech conditions in exposed subjects than controls. No group differences were found for cortical responses to novel sounds.

CONCLUSIONS

Long-term noise exposure altered the strength and the hemispheric organization of speech-sound discrimination and decreased the speed of sound-change processing.

SIGNIFICANCE

Subpathological changes in cortical responses to sounds may occur even in subjects without a peripheral damage but continuously exposed to noisy auditory environments.

Long-term exposure to noise impairs cortical sound processing and attention control

Long-term exposure to noise impairs human health, causing pathological changes in the inner ear as well as other anatomical and physiological deficits. Numerous individuals are daily exposed to excessive noise. However, there is a lack of systematic research on the effects of noise on cortical function. Here we report data showing that long-term exposure to noise has a persistent effect on central auditory processing and leads to concurrent behavioral deficits. We found that speech-sound discrimination was impaired in noise-exposed individuals, as indicated by behavioral responses and the mismatch negativity brain response. Furthermore, irrelevant sounds increased the distractibility of the noise-exposed subjects, which was shown by increased interference in task performance and aberrant brain responses. These results demonstrate that long-term exposure to noise has long-lasting detrimental effects on central auditory processing and attention control.

A physiological correlate for the intolerance to both internal and external sounds

The notion that stress can induce chronic tinnitus, or increase its intensity, is predominant in the literature on tinnitus. However, there is little empirical support for this claim, since previous studies rely merely on subjective reports. In the present study, we used an objective physiological measure of stress (i.e., basal secretion of the stress hormone cortisol), in order to assess the relationship between tinnitus and stress. We hypothesized that tinnitus, a permanent internal sound, should behave as a stressor and should be accompanied by chronically elevated cortisol levels in individuals with severe tinnitus. In addition, we hypothesized that suffering from severe tinnitus should generalize to an intolerance towards external sounds. Two groups each comprised of 18 participants (with and without tinnitus) matched on education and health status participated in the study. Tinnitus severity, as assessed by tinnitus-related distress, was high in half of the tinnitus participants, and low in the other half. Basal cortisol levels were measured using saliva samples (five saliva samples per day for 3 days within a week) taken in the participant's natural environment. Intolerance to external sounds was assessed psychometrically. The high tinnitus-related distress group had chronic cortisol levels greater than both the low tinnitus-related distress and control groups, and also displayed greater intolerance to external sounds. The low tinnitus-related distress and control groups did not differ from each other on either of these measures. Our study thus provides the first physiological and empirical evidence of a link between intolerance to both internal (tinnitus) and external sounds in persons with tinnitus, and is compatible with the clinical observation that severe tinnitus is associated with high stress levels.

Effects of Occupational Noise Exposure on Blood Pressure

We measured 24-hour ambulatory blood pressure and 16-hour noise exposure continuously for 20 automobile workers, and used linear mixed-effects regression models to estimate transient and sustained effects of noise exposure on blood pressure. The occupational noise levels of the high-exposure workers with 85 +/- 8 dBA were significantly higher than those of the low-exposure workers with 59 +/- 4 dBA (P < 0.05). We found a significant difference of 16 +/- 6 mm Hg in sleep-time systolic blood pressure (SBP) existed between 2 exposure groups, and a marginal increase of 1 mm Hg SBP per 1-dBA increase in occupational noise exposure at a 60-minute lag time during work (P = 0.07). Occupational noise exposure had both transient and sustained effects on workers' SBP.