The article covers changes in occupational cardiovascular risk for workers of nonferrous,metallurgy. Findings are that exposure to noise up to 94 dB with length of service increases possible atherosclerosis and metabolic syndrome. With 5 years of service, risk of the predicted conditions increases by 40.5%. When occupational exposure lasts over 5 years, risk of arterial hypertension increases. A group of workers without exposure to occupational factors appeared to have no connection between length of service and metabolic syndrome and arterial hypertension. Risk evolution modelling proved that risk of functional disorders in nonferrous metallurgy workers becomes unacceptable after 5 years of service (cardiovascular disorders are critical).
The hospital sound environment is complex. Alarms, medical equipment, activities, and ventilation generate noise that may present occupational problems as well as hinder recovery among patients. In this study, sound measurements and occupant evaluations were conducted in a neurological intensive care unit. Staff completed questionnaires regarding psychological and physiological reactions to the sound environment. A-weighted equivalent, minimum, and maximum (L(Aeq),L(AFMin),L(AFMax)) and C-weighted peak (L(CPeak)) sound pressure levels were measured over five days at patient and staff locations. Acoustical descriptors that may be explored further were investigated, including level distributions, restorative periods, and spectral content. Measurements near the patients showed average L(Aeq) values of 53-58 dB. The mean length of restorative periods (L(Aeq) below 50 dB for more than 5 min) was 9 and 13 min for day and night, respectively. Ninety percent of the time, the L(AFMax) levels exceeded 50 dB and L(CPeak) exceeded 70 dB. Dosimeters worn by the staff revealed higher noise levels. Personnel perceived the noise as contributing to stress symptoms. Compared to the majority of previous studies, this study provides a more thorough description of intensive care noise and aids in understanding how the sound environment may be disruptive to occupants.
Effect of high speed turbine dental drill noise (DDN) on dentists' hearing at present and during the era of noisier drills was investigated. Hearing of two generations of dentists, power spectral density (PSD) functions of DDN from various drills and the equivalent level (LAeq) of a modern dental operatory were studied. The LAeq was 65 dB with 1 and 50% probability distribution levels of 74 and 57 dB, respectively. DDN was tonal with the spectrum peak always above 6 kHz, containing within 128 Hz frequency band 28-85% of the total noise energy in the PSD function. A cartridge type ball bearing drill from early 1960's was found noisier than an air bearing drill or a modern sealed head ball bearing drill by 8.5 and 5 dB, respectively. Sound pressure levels of DDN ranged from 68 to 79 dBA, being within safe limits. The high values earlier reported for cartridge type or worn drills could not be verified. Hearing of dentists free from clear ear pathology was found good and very similar to the reference, representing a population with no exposure to noise. There was no difference in hearing of 46 dentists 33-42 years of age, examined in 1973 and among whom there had been exposure to early and noisier drill, as compared to hearing of 56 dentists of similar age and years in dentistry, examined in 1988 and who had only been exposed to quieter drills of the 1970's. Noise dose and audiometric measurements were in agreement and indicated that DDN is not and has never been a risk to dentists' hearing.
In a cohort study of lumber mill workers' exposure to noise and incidence of heart disease, initial noise estimates were likely overestimated because they did not account for reductions afforded by the use of hearing protection. As such information was seldom available for individual workers, modeling was necessary to predict hearing protection use and derive adjusted noise measures.
To develop a multilevel model of the likelihood of use of hearing protection devices (HPDs) for British Columbia (Canada) lumber mill workers.
The study population included 13,147 workers in 14 sawmills for whom we had information on HPD use. Subjects self-reported their use of hearing protectors during routine hearing tests over their work history period. Separate multilevel logistic regression models with increasing complexity were developed for a subcohort of workers with complete information (n = 1493) and for a subcohort comprised subjects with hearing tests coinciding with their jobs (n = 10 203). The models included random intercepts for worker and for sawmill.
HPD use was associated in both subcohorts with factors such as noise exposure and age. We also showed that specific jobs (such as sawfiling) and departments (planer, in particular) were strongly associated with the use of HPDs. The model illustrates the quantitative importance of including a hierarchical structure which allows for explaining potential sources of outcome variability.
We developed a hierarchical model to predict hearing protection use to enable correction of exposure assessments for use in retrospective epidemiological studies. We showed that this was feasible even in the absence of complete determinant information.
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.
The aim of this study was to assess the joint effect of job strain and both road-traffic and occupational noise on myocardial infarction (MI).
We conducted a population based case-control study on first time MI in Stockholm County during 1992-1994. Participants answered a questionnaire and underwent a physical examination. Residential road-traffic noise exposure was based on residential history combined with information on traffic intensity and distance to nearby roads. Occupational noise exposure was assessed by occupational history combined with a job-exposure matrix derived from measurements. Job strain was based on questions regarding psychological demands and decision latitude. A total of 3050 study participants (1252 cases and 1798 controls) were included in the study.
An increased risk of MI was indicated among participants exposed to road-traffic noise [odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.01-1.51], occupational noise (OR 1.17, 95% CI 0.98-1.41) and job strain (OR 1.39, 95% CI 1.17-1.65). Participants exposed to one, two, or three of these factors showed an increased risk (OR 1.16, 95% CI 0.97-1.40, OR 1.57, 95% CI 1.24-1.98, and OR 2.27, 95% CI 1.41-3.64, respectively). Exposure to two or three of these factors occurred among about 20% of the controls.
Our results indicate that exposure to a combination of noise exposure and job strain increases the risk of MI substantially. Such exposures affect a considerable part of the population, which has relevance for prioritization of preventative measures.
The results from studies of loud noise exposure and acoustic neuroma are conflicting. A population-based case-control study of 451 acoustic neuroma patients and 710 age-, sex-, and region-matched controls was conducted in Sweden between 2002 and 2007. Occupational exposure was based on historical measurements of occupational noise (321 job titles summarized by a job exposure matrix) and compared with self-reported occupational noise exposure. We also evaluated self-reported noise exposure during leisure activity. Conditional logistic regression was used to estimate odds ratios. There was no statistically significant association between acoustic neuroma and persistent occupational noise exposure, either with or without hearing protection. Exposure to loud noise from leisure activity without hearing protection was more common among acoustic neuroma cases (odds ratio = 1.47, 95% confidence interval: 1.06, 2.03). Statistically significant odds ratios were found for specific leisure activities including attending concerts/clubs/sporting events (odds ratio = 1.82, 95% confidence interval: 1.09, 3.04) and participating in workouts accompanied by loud music (odds ratio = 2.84, 95% confidence interval: 1.37, 5.89). Our findings do not support an association between occupational exposure to loud noise and acoustic neuroma. Although we report statistically significant associations between leisure-time exposures to loud noise without hearing protection and acoustic neuroma, especially among women, we cannot rule out recall bias as an alternative explanation.
Our main purpose was to investigate any relationship between noise exposure levels in the workplace, degree of hearing loss (HL), and the relative risk of accident (OR of single or multiple events).
We conducted a retrospective study of 52 982 male workers aged 16-64 years with long-standing exposures to occupational noise over a 5-year period, using "hearing status" and "noise exposure" from the registry held by the Quebec National Institute of Public Health. Information on work-related accidents was obtained from the Quebec Workers' Compensation Board. Hearing threshold level measurements and noise exposures were regressed on the numbers of accidents after adjusting for age.
Exposure to extremely noisy environments (L(eq8h) (equivalent noise level for 8 h exposure) > or =90 dBA) is associated with a higher relative risk of accident. The severity of hearing impairment (average bilateral hearing threshold levels at 3, 4 and 6 kHz) increases the relative risk of single and multiple events when threshold levels exceed 15 dB of hearing loss. The relative risk of multiple events (four or more) is approximately three times higher among severely hearing-impaired workers who are exposed to L(eq8h) > or =90 dBA.
Single and multiple events are associated with high noise exposure and hearing status. This suggests that reducing noise exposure contributes to increased safety in noisy industries and prevents hearing loss. Hearing-impaired workers assigned to noisy workstations should be provided with assistive listening devices and efficient communication strategies should be implemented.
To analyze whether noise sensitivity increases the risk of disability pension (DP).
Questionnaire data of a sample of 706 Finnish twin individuals (age range, 31 to 65 years) with record linkage to information on DP during 16 years of follow-up were analyzed using individual and pairwise Cox proportional hazards models.
Noise sensitivity increased the risk of DP (hazard ratio = 1.41; 95% confidence interval [CI]: 1.03 to 1.93) and DP due to musculoskeletal disorders (hazard ratio = 1.63; 95% CI: 1.00 to 2.66). In within-pair analyses, noise sensitivity increased the risk of DP: among all twin pairs, odds ratio was 1.80 (95% CI: 1.08 to 3.06).
Noise sensitivity may be a potential risk factor for disability retirement. It is associated with DP independently of familial background and genetic factors.