Showing papers in "Noise & Health in 2011"

Cardiovascular effects of noise

Abstract: The auditory system is continuously analyzing acoustic information, which is filtered and interpreted by different cortical and subcortical brain structures. According to the general stress concept, repeated temporal changes in biological responses can result in permanent metabolic changes of the organism leading to chronic diseases in the long run. Most epidemiological studies have been carried out with respect to health effects of occupational noise and – regarding environmental noise – with respect to road and air traffic noise. The studies suggest a higher risk of cardiovascular diseases, including high blood pressure and ischemic heart diseases in subjects persistently exposed to high levels of noise at the workplace or transportation noise outside their dwellings. Different expert groups have evaluated the evidence of the association. Road traffic noise levels at the facades of the houses exceeding 65 dB(A) during daytime and 55 dB(A) during the night were considered to be detrimental to cardiovascular health. Adverse health effects due to aircraft noise were found at even lower average noise levels. Most of the studies suggest a continuous increase in risk with increasing noise level. Based on meta-analyses, exposure–response relationships and regression coefficients have been derived that can be used for a quantitative risk assessment and burden of disease calculations in public health.

Evaluating the impact of wind turbine noise on health-related quality of life.

Abstract: We report a cross-sectional study comparing the health-related quality of life (HRQOL) of individuals residing in the proximity of a wind farm to those residing in a demographically matched area sufficiently displaced from wind turbines. The study employed a nonequivalent comparison group posttest-only design. Self-administered questionnaires, which included the brief version of the World Health Organization quality of life scale, were delivered to residents in two adjacent areas in semirural New Zealand. Participants were also asked to identify annoying noises, indicate their degree of noise sensitivity, and rate amenity. Statistically significant differences were noted in some HRQOL domain scores, with residents living within 2 km of a turbine installation reporting lower overall quality of life, physical quality of life, and environmental quality of life. Those exposed to turbine noise also reported significantly lower sleep quality, and rated their environment as less restful. Our data suggest that wind farm noise can negatively impact facets of HRQOL.

Relationship between noise annoyance from road traffic noise and cardiovascular diseases: a meta-analysis.

Abstract: Road traffic noise is an important source of noise annoyance in the community. We performed a meta-analysis to assess whether there is an association between noise annoyance from road traffic noise and cardiovascular diseases (arterial hypertension and ischemic heart disease) in adult population. The meta-analysis included studies that: a. had noise annoyance as exposure, quantified either as "annoyed versus non-annoyed" or with various scales collected by standardized questionnaires; b. arterial hypertension or ischemic heart disease as outcome; c. had included only adult population (age >18 years); d. the studies had to have as effect size odds ratios or relative risk. From the individual studies those odds ratios were selected for meta-analysis which compared most distant categories. Eight studies that fulfilled criteria published between 1992 and 2006 were included in the meta-analysis: 6 studies had a cross-sectional design, 1 study had a case-control-design and 1 study had a cohort design. Increased annoyance was significantly associated with arterial hypertension (pooled risk estimate = 1.16, 95% confidence interval 1.02-1.29) while the association with ischemic heart disease did not reach statistical significance (pooled risk estimate = 1.07, 95% confidence interval 0.99-1.14). No publication bias was evidenced. The results of this meta-analysis demonstrated the existence of a positive and significant association between noise annoyance from road traffic and the risk of arterial hypertension and a positive yet insignificant association between noise annoyance and the risk of ischemic heart disease.

High-frequency audiometry: A means for early diagnosis of noise-induced hearing loss

Abstract: Noise-induced hearing loss (NIHL), an irreversible disorder, is a common problem in industrial settings. Early diagnosis of NIHL can help prevent the progression of hearing loss, especially in speech frequencies. For early diagnosis of NIHL, audiometry is performed routinely in conventional frequencies. We designed this study to compare the effect of noise on high-frequency audiometry (HFA) and conventional audiometry. In a historical cohort study, we compared hearing threshold and prevalence of hearing loss in conventional and high frequencies of audiometry among textile workers divided into two groups: With and without exposure to noise more than 85 dB. The highest hearing threshold was observed at 4000 Hz, 6000 Hz and 16000 Hz in conventional right ear audiometry, conventional left ear audiometry and HFA in each ear, respectively. The hearing threshold was significantly higher at 16000 Hz compared to 4000. Hearing loss was more common in HFA than conventional audiometry. HFA is more sensitive to detect NIHL than conventional audiometry. It can be useful for early diagnosis of hearing sensitivity to noise, and thus preventing hearing loss in lower frequencies especially speech frequencies.

Hearing loss among classical-orchestra musicians.

Abstract: This study intended to evaluate classical musicians' risk of hearing loss. We studied 63 musicians from four Helsinki classical orchestras. We measured their hearing loss with an audiometer, found their prior amount of exposure to sound and some individual susceptibility factors with a questionnaire, measured their present sound exposure with dosimeters, and tested their blood pressure and cholesterol levels, then compared their hearing loss to ISO 1999-1990's predictions. The musicians' hearing loss distribution corresponded to that of the general population, but highly exposed musicians had greater hearing loss at frequencies over 3 kHz than less-exposed ones. Their individual susceptibility factors were low. Music deteriorates hearing, but by less than what ISO 1999-1990 predicted. The low number of individual susceptibility factors explained the difference, but only reduced hearing loss and not the prevalence of tinnitus.

Cardiovascular effects of environmental noise: research in Austria.

Abstract: Cardiovascular effects of noise rank second in terms of disability-adjusted life year (DALYs) after annoyance. Although research during the past decade has consolidated the available data base, the most recent meta-analysis still shows wide confidence intervals - indicating imprecise information for public health risk assessment. The alpine area of Tyrol in the Austrian part of the Alps has experienced a massive increase in car and heavy goods traffic (road and rail) during the last 35 years. Over the past 25 years small-, middle-, and large-sized epidemiological health surveys have been conducted - mostly within the framework of environmental health impact assessments. By design, these studies have emphasized a contextually driven environmental stress perspective, where the adverse health effects on account of noise are studied in a broader framework of environmental health, susceptibility, and coping. Furthermore, innovative exposure assessment strategies have been implemented. This article reviews the existing knowledge from these studies over time, and presents the exposure-response curves, with and without interaction assessment, based on standardized re-analyses and discusses it in the light of past and current cardiovascular noise effects research. The findings support relevant moderation by age, gender, and family history in nearly all studies and suggest a strong need for consideration of non-linearity in the exposure-response analyses. On the other hand, air pollution has not played a relevant role as a moderator in the noise-hypertension or the noise-angina pectoris relationship. Finally, different noise modeling procedures can introduce variations in the exposure response curves, with substantive consequences for public health risk assessment of noise exposure.

Cardiovascular effects of environmental noise: Research in Sweden

Abstract: In Sweden, as in many other European countries, traffic noise is an important environmental health issue. At present, almost two million people are exposed to average noise levels exceeding the outdoor national guideline value (55 dB(A)). Despite efforts to reduce the noise burden, noise-related health effects, such as annoyance and sleep disturbances, are increasing. The scientific interest regarding more serious health effects related to the cardiovascular system is growing, and several experimental and epidemiological studies have been performed or are ongoing. Most of the studies on cardiovascular outcomes have been related to noise from road or aircraft traffic. Few studies have included railway noise. The outcomes under study include morning saliva cortisol, treatment for hypertension, self-reported hypertension, and myocardial infarction. The Swedish studies on road traffic noise support the hypothesis of an association between long-term noise exposure and cardiovascular disease. However, the magnitude of effect varies between the studies and has been shown to depend on factors such as sex, number of years at residence, and noise annoyance. Two national studies have been performed on the cardiovascular effects of aircraft noise exposure. The first one, a cross-sectional study assessing self-reported hypertension, has shown a 30% risk increase per 5 dB(A) noise increase. The second one, which to our knowledge is the first longitudinal study assessing the cumulative incidence of hypertension, found a relative risk (RR) of 1.10 (95% CI 1.01 - 1.19) per 5 dB(A) noise increase. No associations have been found between railway noise and cardiovascular diseases. The findings regarding noise-related health effects and their economic consequences should be taken into account in future noise abatement policies and community planning.

The efficacy of N-acetylcysteine to protect the human cochlea from subclinical hearing loss caused by impulse noise: A controlled trial

Abstract: In military outdoor shooting training, with safety measures enforced, the risk of a permanent, noise-induced hearing loss is very small. But urban warfare training performed indoors, with reflections from walls, might increase the risk. A question is whether antioxidants can reduce the negative effects of noise on human hearing as it does on research animals. Hearing tests were performed on a control group of 23 military officers before and after a shooting session in a bunker-like room. The experiments were repeated on another group of 11 officers with peroral adminstration of N-acetyl­cysteine (NAC), directly after the shooting. The measurements performed were tone thresholds; transient-evoked otoacoustic emissions, with and without contralateral noise; and psycho­acoustical modulation transfer function (PMTF), thresholds for brief tones in modulated noise. Effects from shooting on hearing thresholds were small, but threshold behavior supports use of NAC treatment. On the PMTF, shooting without NAC gave strong effects. Those effects were like those from continuous noise, which means that strict safety measures should be enforced. The most striking finding was that the non-linearity of the cochlea, that was strongly reduced in the group without NAC, as manifested by the PMTF-results, was practically unchanged in the NAC-group throughout the study. NAC treatment directly after shooting in a bunkerlike room seems to give some protection of the cochlea.

Effects of noise from non-traffic-related ambient sources on sleep: Review of the literature of 1990-2010

Abstract: This article reviews the literature about the effects of specific non-traffic-related ambient noise sources on sleep that appeared in the last two decades. Although everybody is faced with noise of non-traffic and non-industry origin (e.g. sounds made by neighbors, talk, laughter, music, slamming doors, structural equipment, ventilation, heat pumps, noise from animals, barking dogs, outdoor events etc.), little scientific knowledge exists about its effects on sleep. The findings of the present extensive literature search and review are as follows: Only a small number of surveys, laboratory and field studies about mainly neighborhood, leisure and animal noise have been carried out. Most of them indicate that ambient noise has some effect on human sleep. However, a quantitative meta-analysis and comparison is not possible due to the small number of studies available and at times large differences in quality.

Cardiovascular effects of environmental noise: research in the United Kingdom.

Abstract: Although the auditory effects of noise on humans have been established, the non-auditory effects are not so well established. The emerging links between noise and cardiovascular disease (CVD) have potentially important implications on public health and policy. In the United Kingdom (UK), noise from transport is a problem, where more than half of the population is exposed to more than the recommended maximum day-time noise level and just under three-quarters of the population live in areas where the recommended night-time noise level is exceeded. This review focuses on findings from studies conducted in the UK that examined environmental noise and cardiovascular disease. There were statistically no significant associations between road traffic noise and incident ischemic heart disease in the Caerphilly and Speedwell studies, but there was a suggestion of effects when modifying factors such as length of residence, room orientation, and window opening were taken into account. In a sample stratified by pre-existing disease a strongly increased odds of incident ischemic heart disease for the highest annoyance category was found compared to the lowest among men without pre-existing disease (OR = 2.45, 95%1.13 - 5.31), which was not found in men with pre-existing disease. In the Hypertension and exposure to noise near airports (HYENA) study, night time aircraft noise exposure (L night ) was associated with an increased risk of hypertension, in fully adjusted analyses. A 10-dB increase in aircraft noise exposure was associated with an odds ratio of 1.14 (95%CI, 1.01 - 1.29). Aircraft noise was not consistently related to raised systolic blood pressure in children in the road traffic and aircraft noise exposure and children's cognition and health (RANCH) study. There is some evidence of an association among environmental noise exposure and hypertension and ischemic heart disease in the UK studies; further studies are required to explore gender differences, the effects of day and night time exposure, and exposure modifying factors.

Individual fit-testing of earplugs: A review of uses

Abstract: Individual fit-testing of earplugs is an exciting new trend in hearing conservation. This article reviews how this technology is being used to protect noise-exposed workers. Earplug fit-testing systems are becoming more commercially available and more feasible for field use. Individual fit-testing is no longer used only for research investigations but is being incorporated in Hearing Conservation Programs (HCP) to improve training, document protection and evaluate the effectiveness of the hearing protector element of an effective HCP.

Occupational exposure to noise and the prevalence of hearing loss in a Belgian military population: A cross-sectional study

Abstract: The armed forces are highly exposed to occupational noise. The aim of this study was to evaluate the prevalence and noise exposures associated with the severity of hearing loss (HL) in a Belgian military population. A cross-sectional study was carried out at the Centre for Medical Expertise (CME) and in four Units of Occupational Medicine (UOM). Hearing thresholds were determined by audiometry. The examination included a questionnaire on hearing-related medical history, and noise exposure in military and leisure time activity. A multinomial logistic regression model was used to assess the association of the severity of HL with tinnitus, with the military occupation, and with noise exposures. Of the 2055 subjects aged 18-55 years, 661 (32.2%) had a slight HL (25-40 dB), 280 (13.6%) had a moderate HL (45-60 dB) and 206 (10.0%) had a severe HL (>60 dB) of 4 and 6 kHz for both ears. The prevalence of slight, moderate and severe HL increased significantly with age and was higher for subjects from Paracommando and infantry units. Fighting in Built-Up Area (FIBUA) training, shooting with large caliber weapons, and participation in military exercises were the best determinants of HL in this population. These results suggest that subjects from infantry and Paracommando units run the highest risk of HL because they are exposed to very loud noises in their professional life, like large caliber shooting and FIBUA training.

Increased vitamin plasma levels in Swedish military personnel treated with nutrients prior to automatic weapon training

Abstract: Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue. The development of novel therapeutic agents to reduce NIHL will potentially benefit multiple very large noise-exposed populations. Oxidative stress has been identified as a significant contributor to noise-induced sensory cell death and NIHL, and several antioxidant strategies have now been suggested for potential translation to human subjects. One such strategy is a combination of beta-carotene, vitamins C and E, and magnesium, which has shown promise for protection against NIHL in rodent models, and is being evaluated in a series of international human clinical trials using temporary (military gunfire, audio player use) and permanent (stamping factory, military airbase) threshold shift models (NCT00808470). The noise exposures used in the recently completed Swedish military gunfire study described in this report did not, on average, result in measurable changes in auditory function using conventional pure-tone thresholds and distortion product otoacoustic emission (DPOAE) amplitudes as metrics. However, analysis of the plasma samples confirmed significant elevations in the bloodstream 2 hours after oral consumption of active clinical supplies, indicating the dose is realistic. The plasma outcomes are encouraging, but clinical acceptance of any novel therapeutic critically depends on demonstration that the agent reduces noise-induced threshold shift in randomized, placebo-controlled, prospective human clinical trials. Although this noise insult did not induce hearing loss, the trial design and study protocol can be applied to other populations exposed to different noise insults.

Road traffic noise, annoyance and community health survey - A case study for an Indian city

Abstract: The present study is aimed to investigate the impact of noise pollution on residents/community residing near roadside. The degree of annoyance was assessed by means of a questionnaire. It was found that among all noise-generating sources, road traffic was the major source of noise followed by factory/machines. A health survey reported about 52% of population was suffering by frequent irritation. 46% respondent felt hypertension, and 48.6% observed loss of sleep due to noise pollution. Common noise descriptors were also recorded at all the selected sites. It was found that the Leq values were higher (range 73-86) compared to the permissible values (65 dBA) prescribed by the Central Pollution Control Board, New Delhi. Further, regression equations were developed between various noise indices and percentage of population highly annoyed, and a strong correlation was also observed.

Effects of training on hearing protector attenuation

Abstract: The effect of training instruction, whether presented as the manufacturer's printed instructions, a short video training session specific to the product, or as a one-on-one training session was evaluated using four hearing protection devices with eight groups of subjects. Naive subjects were recruited and tested using three different forms of training: written, video, and individual training. The group averages for A-weighted attenuation were not statistically significant when compared between the video or the written instruction conditions, regardless of presentation order. The experimenter-trained A-weighted attenuations were significantly greater than the written and video instruction for most of the protectors and groups. For each earplug, the noise reduction statistic for A-weighting (NRS A ) and the associated confidence intervals were calculated for the 80 th and 20 th percentiles of protection. Across subject groups for each protector, the differences between NRS A ratings were found to be not statistically significant. Several comparisons evaluating the order of testing, the type of testing, and statistical tests of the performance across the groups are presented.

The possible influence of noise frequency components on the health of exposed industrial workers--a review

Abstract: Noise is a common occupational health hazard in most industrial settings. An assessment of noise and its adverse health effects based on noise intensity is inadequate. For an efficient evaluation of noise effects, frequency spectrum analysis should also be included. This paper aims to substantiate the importance of studying the contribution of noise frequencies in evaluating health effects and their association with physiological behavior within human body. Additionally, a review of studies published between 1988 and 2009 that investigate the impact of industrial/occupational noise on auditory and non-auditory effects and the probable association and contribution of noise frequency components to these effects is presented. The relevant studies in English were identified in Medknow, Medline, Wiley, Elsevier, and Springer publications. Data were extracted from the studies that fulfilled the following criteria: title and/or abstract of the given study that involved industrial/occupational noise exposure in relation to auditory and non-auditory effects or health effects. Significant data on the study characteristics, including noise frequency characteristics, for assessment were considered in the study. It is demonstrated that only a few studies have considered the frequency contributions in their investigations to study auditory effects and not non-auditory effects. The data suggest that significant adverse health effects due to industrial noise include auditory and heart-related problems. The study provides a strong evidence for the claims that noise with a major frequency characteristic of around 4 kHz has auditory effects and being deficient in data fails to show any influence of noise frequency components on non-auditory effects. Furthermore, specific noise levels and frequencies predicting the corresponding health impacts have not yet been validated. There is a need for advance research to clarify the importance of the dominant noise frequency contribution in evaluating health effects.

Risk of hypertension related to road traffic noise among reproductive-age women.

Abstract: Chronic noise exposure is associated with adverse pathophysiological effects, which may contribute to the progression of hypertension. However, evidence supporting its effect on women is still inconsistent. The aim of the study was to examine the hypertension risk related to road traffic noise in residential settings in an urban community amongst reproductive-aged women. Cross-sectional study data including 3,121 pregnant women, 20-45 years old, and a geographic information system (GIS) to assess the average road noise (LAeq 24 hr) for every subject at the current residential address were used. Effects on physician-diagnosed hypertension were estimated by logistic regression with adjustments for age, social status, marital status, education, alcohol consumption, ethnic group, parity, body mass index, chronic disease, and exposure duration. The prevalence of hypertension amongst women aged 20-45 years in the lowest exposure category was 13.1% in comparison to 13.6% and 18.1% amongst those exposed to the medium and the highest exposure category, respectively. After making adjustments for the selected variables, no exposure effects [Odds ratio (OR) ≈ 1.0] were noted in the medium exposure category [51-60 dB(A)]. However, a slight increase was noted in the highest exposure category [≥61 dB(A)), OR 1.36; 95% CI 0.86-2.15]. The effect was more pronounced amongst women aged 30-45 years and a positive exposure-response relation was indicated for hypertension: An effect was seen at noise levels 51-60 dB(A) (OR = 1.03; 95% CI 0.72-1.49) and at >61 dB(A) (OR = 1.94, 95% CI 1.01-3.72). The present study shows some evidence for an association between the residential road traffic noise and hypertension amongst reproductive-aged women, and an exposure-response relationship.

Symphony orchestra musicians' use of hearing protection and attenuation of custom-made hearing protectors as measured with two different real-ear attenuation at threshold methods

Abstract: Despite a high level of sound exposure and a fairly large selection of earplugs available, musicians have often been reported to use personal hearing protectors only seldom. For better hearing conservation, it is important to identify and eliminate the causes for the low motivation to use hearing protection. We explored the usage rate of custom-molded musician's earplugs (ER-15) among 15 symphony orchestra musicians with a questionnaire, and measured the attenuation properties of their earplugs with a Real-Ear Attenuation at Threshold (REAT) procedure in a sound field. Earplug use was found to be low, and the musicians reported that earplugs hampered listening to their own and their colleagues' playing; earplugs affected either timbre or dynamics, or both. Additionally, several reasons related to discomfort of use were itemized, but the musicians who consistently used their earplugs did so in spite of problems with use. The REAT values obtained in sound field were relatively close to the manufacturer's nominal specifications, being 13.7 dB, on average. In the frequency range studied (0.125-8 kHz), individual variation in REAT was, however, up to 15 dB across the measured frequencies. Fluctuation in attenuation might be related to low use of hearing protectors, and REAT measured at fixed center frequencies may be too robust a method to uncover it. We therefore tested 10 additional subjects to find out whether a sweeping signal used in Bιkιsy audiometry would bring more detailed information on earplug attenuation. Mean attenuation was found to be somewhat closer to the nominal attenuation of the ER-9 and ER-15 earplugs up to about 1 kHz, whereas REAT measurements in sound field revealed more even attenuation at frequencies between 1 and 6 kHz. No significant association was found between earplug attenuation properties and earplug use. It was concluded that support and determination to get accustomed to hearing protector use are important factors in hearing conservation.

The influence of military service on auditory health and the efficacy of a Hearing Conservation Program.

Abstract: The influence of military service on self-assessed hearing symptoms and measured auditory function was studied as well as the efficacy of the Hearing Conservation Program (HCP) of the Swedish Armed Forces. 839 conscripts were recruited for the study at reporting to military service. They were all exposed to noise over the risk-limits from weapons and vehicles and used earmuffs and/or earplugs. Questionnaires and pure tone screening audiometry were studied at the start and the end of the military service. Retrospective information regarding audiometry at conscription before military service was included as control. The prevalence values of tinnitus were 23% before and 32% after the service and of sensitivity to noise 16% and 19% respectively. The prevalence values of hearing impairment were 6.3% at conscription, 14.5% at reporting to military service, and 24% after the training period. The incidence values of hearing decline were 3.7% during the period with no military noise exposure and 6.6% during the military service. Acoustic accident increased the risk of worsened tinnitus and sensitivity to noise four times and for a high frequency hearing decline six times. We observed elevated prevalence values of tinnitus, sensitivity to noise and hearing impairment at discharge compared to before military service. We observed an elevated risk of hearing decline during military service. Acoustic accident increased the risk of tinnitus, noise sensitivity and hearing decline. We suggest improvements regarding inclusion criteria for military service, and for education regarding the HCP.

Hearing impairment among workers exposed to excessive levels of noise in ginning industries.

Abstract: Cotton ginning workers have a risk of hearing loss due to excessive noise levels at the workplace environment. In this study, estimates of typical sound levels prevailing at the workplace environment and its effects on hearing ability of the exposed workers were made among cotton ginning workers. Data on self-reported health status was collected by a questionnaire survey at 10 cotton ginning industries located at Jalgaon district of Maharashtra state, India. The cotton ginning workers were exposed to continuous noise levels between 89 and 106 dBA. The hearing ability of the subjects was accessed by pure tone audiometry. The results of audiometry show mild, moderate and moderately severe degree of hearing impairment among the cotton ginning workers. The data generated during the study show that hearing loss was significantly associated with period of exposure to the workplace noise (P <0.0001). The prevalence of audiometric hearing impairment defined as a threshold average greater than 25 dB hearing level was 96% for binaural low-frequency average, 97% for binaural mid frequency average and 94% for binaural high-frequency average in the cotton ginning workers. We recommend the compulsory use of personal protective equipment like ear plug by the cotton ginning workers at the workplace environment. A regular maintenance of ginning and pressing machineries will avoid the emission of excessive noise at the workplace environment of cotton gins. A regular periodic medical examination is necessary to measure the impact of workplace noise on the health of cotton ginning workers.

Chronic exposure of juvenile rats to environmental noise impairs hippocampal cell proliferation in adulthood.

Abstract: Increasing evidence indicates that chronic exposure to environmental noise may permanently affect the central nervous system The aim of this study was to evaluate the long-term effects of early exposure to environmental noise on the hippocampal cell proliferation of the adult male rat Early-weaned Wistar rats were exposed for 15 days to a rats' audiogram-fitted adaptation to a noisy environment Two months later, the rats were injected with the cellular proliferation marker 5΄bromodeoxiuridine (BrdU), and their brains were processed for immunohistochemical analysis Coronal sections were immunolabeled with anti-BrdU antibodies to identify new-born cells in dentate gyrus (DG), cornu amonis areas CA1 and CA3 In addition, blood samples were obtained to evaluate corticosterone serum levels after noise exposure All data are expressed as mean±standard deviation For mean comparisons between groups, we used the Student t test We found an increase in corticosterone serum levels after environmental noise exposure Interestingly, noise-exposed rats showed a long-term reduction of proliferating cells in the hippocampal formation, as compared to controls These findings indicate that chronic environmental noise exposure at young ages produces persistent non-auditory impairment that modifies cell proliferation in the hippocampal formation

Cardiovascular effects of environmental noise: research in Serbia.

Abstract: Research on the cardiovascular effects of noise in Serbia started in the year 2002, including experimental studies on humans and epidemiological studies on the adult and children population of Belgrade and Pancevo. Experimental exposure to noise [L eq = 89 dB (A)] had a hypodynamic effect, significantly lowering the cardiac index, cardiac work, and pump performance (P 45 dB (A)] and quiet areas [(L night , 8h ≤ 45 dB (A)] were 23.6% and 17.5%, respectively. The adjusted odds ratio (OR) for hypertension of the exposed group was 1.58 (95% CI = 1.03 - 2.42, P = 0.038), where men living in quiet streets were taken as a reference category. Associations between road traffic noise and blood pressure were also investigated in 328 preschool children in Belgrade. The systolic blood pressure was significantly higher among children from noisy residences and kindergartens, compared to children from both quiet environments (97.30 ± 8.15 and 92.33 ± 8.64 mmHg, respectively, P < 0.01). As a continuation of the study on preschool children, investigations were also carried out on 856 school children, aged between seven and eleven years, in Belgrade. It was found that systolic pressure was significantly higher among children from noisy schools and quiet residences, compared to children from both quiet environments (102.1 ± 9,3 and 100.4 ± 10.4 mmHg, respectively, P < 0.01).

Noise-induced hearing loss in agriculture: Creating partnerships to overcome barriers and educate the community on prevention

Abstract: Noise-induced hearing loss (NIHL) is a common and preventable injury for farmers. Farmers are frequently exposed to excessive noise, ranking among the top three occupations and industries with the highest risk for hearing loss. Use of hearing protection among farmers is not common. Although the age when NIHL begins among farmers is unknown, its prevalence is higher among male adolescents who live and work on farms. The purpose of this paper is to describe how NIOSH created partnerships to promote hearing conservation for this hard-to-reach population. Partnerships included organizations and individuals who were trusted sources of information for the target population, young farmers 14-35 years of age and their families, and those who had linkages in rural communities. NIOSH engaged partners through exhibits and train-the-trainer workshops at state or national conventions. NIOSH workshops included basic information on NIHL as well as information on free or low-lost resources that participants could use in training others at schools and community events. People with hearing conservation expertise have an important role and many opportunities to improve the knowledge and implementation of hearing conservation among those in agriculture.

Noise exposure of musicians of a ballet orchestra.

Abstract: With over 70 dancers and its own orchestra, The National Ballet of Canada ranks amongst the world's top dance companies. It performs three seasons annually: fall, winter and summer, plus many shows of Tchaikovsky's Nutcracker. The 70-strong orchestra plays an average of 360 hours/year including rehearsals and performances. Rehearsals are held at two locations: one in a ballet rehearsal room with little or no absorption, and the other in an acoustically treated location. Performances are held in the Four Seasons Centre for the Performing Arts in Toronto. The present survey was done at the request of the National Ballet, since the musicians complained of excessive sound levels and were concerned about possible hearing losses. The survey was performed using five dosimeters Quest Mod 300 during 10 performances of the ballet Romeo and Juliet by Sergei Prokofiev, deemed as the noisiest in the whole repertoire. Results of the survey indicate that the noise exposure levels from only the orchestra's activities do not present risk of hearing loss. Exposure due to other musical activities was, however, not included.

A four-part setting on examining the anxiety-provoking capacity of the sound of dental equipment.

Abstract: This paper reports the results of a four-part questionnaire survey to assess the effects of the sound of dental equipment on people's perceptions and dental anxiety levels. The convenience sample for the survey comprised 230 dental students and 230 gender and age matched non-dental university students. The subjects were requested to complete the questionnaires themselves. The results show that the sound of dental equipment has a great influence on dental anxiety. Dental students, who are more familiar with the operation of this equipment, are less prone to anxiety when they hear its sound than their non-dental counterparts.

Development and validation of a field microphone-in-real-ear approach for measuring hearing protector attenuation.

Abstract: Numerous studies have shown that the reliability of using laboratory measurements to predict individual or even group hearing protector attenuation for occupationally exposed workers is quite poor. This makes it difficult to properly assign hearing protectors when one wishes to closely match attenuation to actual exposure. An alternative is the use of field-measurement methods, a number of which have been proposed and are beginning to be implemented. We examine one of those methods, namely the field microphone-in-real-ear (F-MIRE) approach in which a dual-element microphone probe is used to measure noise reduction by quickly sampling the difference in noise levels outside and under an earplug, with appropriate adjustments to predict real-ear attenuation at threshold (REAT). We report on experiments that validate the ability of one commercially available F-MIRE device to predict the REAT of an earplug fitted identically for two tests. Results are reported on a representative roll-down foam earplug, stemmed-style pod plug, and pre-molded earplug, demonstrating that the 95% confidence level of the Personal Attenuation Rating (PAR) as a function of the number of fits varies from ± 4.4 dB to ± 6.3 dB, depending on the plug type, which can be reduced to ± 3.1 dB to ± 4.5 dB with a single repeat measurement. The added measurement improves precision substantially. However, the largest portion of the error is due to the user's fitting variability and not the uncertainty of the measurement system. Further we evaluated the inherent uncertainty of F-MIRE vs. the putative "gold standard" REAT procedures finding, that F-MIRE measurement uncertainty is less than one-half that of REAT at most test frequencies. An American National Standards Institute (ANSI) working group (S12/WG11) is currently involved in developing methods similar to those in this paper so that procedures for evaluating and reporting uncertainty on all types of field attenuation measurement systems can be standardized. We conclude that the hearing conservationist now has available a portable, convenient, quick, and easy-to-use system that can improve training and motivation of employees, assign hearing protection devices based on noise exposures, and address other management and compliance issues.

Fit-testing hearing protectors: an idea whose time has come.

Abstract: The performance of hearing protection devices (HPD) worn by individual workers in specific noise-exposure environments has been difficult to assess using the hearing protector ratings printed on HPD packages. Because the role of the HPD in prevention of hearing loss remains as a vital last line of defense against the effects of noise exposure, proper assessment of their performance is increasingly critical. HPD fit-testing procedures now allow the individual fit-testing of HPD to assist in appropriate selection of HPD for individual workers, to aid in training workers on proper use of HPDs, and a range of other applications. Understanding these technologies, their strengths and weaknesses, and appropriate application of the results of fit-testing may enable employers to make improvements in their hearing loss prevention program performance.

Effect of vitamin E supplementation on carbogen-induced amelioration of noise induced hearing loss in man

Abstract: The study explores the effect of occupational noise on oxidative stress status and prophylactic effect of Vitamin E and carbogen (5% CO 2 +95%O 2 ) breathing in alleviating the oxidative damage and conserving the hearing in human volunteers exposed to intense occupational noise. Plasma total antioxidant status, blood glutathione (GSH), malondialdehyde (MDA), antioxidant enzyme activities of GSH peroxidase (EC 1.11.1.9, GPx), superoxide dismutase (EC 1.15.1.1; SOD) in erythrocytes, nitric oxide and nitric oxide synthase in plasma were assessed before and after 6 days of administration of Vitamin E and Carbogen. Results of the study indicate that the exposure to noise for 6 days increased blood concentration of MDA, decreased concentrations of reduced GSH, antioxidant enzyme activity of SOD and plasma total antioxidant status in control (noise) group. Vitamin E- supplemented group showed decline in oxidative stress reflected by significant decrease in blood concentration of MDA and increase in antioxidant enzyme activity of erythrocyte SOD. Results of audiometric studies revealed that breathing of carbogen prevented the development of temporary threshold shift; thereby reducing the risk of noise induced hearing loss.

The challenge of localizing vehicle backup alarms: effects of passive and electronic hearing protectors, ambient noise level, and backup alarm spectral content.

Abstract: A human factors experiment employed a hemi-anechoic sound field in which listeners were required to localize a vehicular backup alarm warning signal (both a standard and a frequency-augmented alarm) in 360-degrees azimuth in pink noise of 60 dBA and 90 dBA. Measures of localization performance included: (1) percentage correct localization, (2) percentage of right--left localization errors, (3) percentage of front-rear localization errors, and (4) localization absolute deviation in degrees from the alarm's actual location. In summary, the data demonstrated that, with some exceptions, normal hearing listeners' ability to localize the backup alarm in 360-degrees azimuth did not improve when wearing augmented hearing protectors (including dichotic sound transmission earmuffs, flat attenuation earplugs, and level-dependent earplugs) as compared to when wearing conventional passive earmuffs or earplugs of the foam or flanged types. Exceptions were that in the 90 dBA pink noise, the flat attenuation earplug yielded significantly better accuracy than the polyurethane foam earplug and both the dichotic and the custom-made diotic electronic sound transmission earmuffs. However, the flat attenuation earplug showed no benefit over the standard pre-molded earplug, the arc earplug, and the passive earmuff. Confusions of front-rear alarm directions were most significant in the 90 dBA noise condition, wherein two types of triple-flanged earplugs exhibited significantly fewer front-rear confusions than either of the electronic muffs. On all measures, the diotic sound transmission earmuff resulted in the poorest localization of any of the protectors due to the fact that its single-microphone design did not enable interaural cues to be heard. Localization was consistently more degraded in the 90 dBA pink noise as compared with the relatively quiet condition of the 60 dBA pink noise. A frequency-augmented backup alarm, which incorporated 400 Hz and 4000 Hz components to exploit the benefits of interaural phase and intensity cues respectively, slightly but significantly improved localization compared with the standard, more narrow-bandwidth backup alarm, and these results have implications for the updating of backup alarm standards.

Noise sensitivity and hearing disability.

Abstract: The aim of this study was to investigate the association of noise sensitivity with self-reported hearing disability and hearing levels, with consideration of the role of self-reported history of noise exposure and use of hearing protectors. The study is based on the Finnish Twin Cohort. In 1988, a noise questionnaire was sent to 1005 twin pairs, 1495 individuals (688 men, 807 women) replied. The age range was 31-88 years. Information on some potential confounders was obtained from the questionnaire in 1981 for the same individuals. A subsample of thirty-eight elderly women with noise sensitivity response from 1988 had audiometry data from 2000 to 2001. Noise sensitivity was associated with self-reported hearing disability among all subjects [odds ratio (OR) 1.55, 95% confidence interval (CI) 1.14-2.12] and among women (OR 1.90, 95% CI 1.19-3.04), but no-more significantly among men (OR 1.31, 95% CI 0.86-1.98). The association was primarily seen among younger subjects (50 years or less). The difference between noise sensitive and non-noise sensitive elderly women in the average of thresholds at frequencies of 0.5-4 kHz in the better ear was not significant (Pr = 0.18). Noise sensitivity did not modify the association of hearing disability with the self-reported history of occupational noise exposure. Noise sensitivity was associated with the use of hearing protectors at work. The study shows the importance of recognizing the noise sensitive in noise effect studies, since sensitivity in annoyance has implications in most of the effect categories.