Jinro Inoue

Urinary 1-hydroxypyrene and 8-hydroxydeoxyguanosine Levels among Coke-oven Workers for 2 Consecutive Days

Urinary 1‐hydroxypyrene and 8‐hydroxydeoxyguanosine Levels among Coke‐oven Workers for 2 Consecutive Days: Thi‐To‐Uyen NGUYEN, et al. Department of Health Policy and Management, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan—

Temporary threshold shifts at 1500 and 2000 Hz induced by loud voice signals communicated through earphones in the pinball industry.

To assess the risk of hearing loss among workers using earphones as communication devices at noisy worksites, we compared temporary threshold shifts (TTS) between ears on which workers wore earphones and ears on which no earphones were worn. We measured ambient noise and personal noise exposure as well as noise generated by and passed through earphones by applying frequency analysis at three pinball facilities during their hours of actual operation. We assessed hearing levels before and after a work shift (prework and postwork) of 54 workers by pure tone audiometry at six frequencies. The time-weighted averages for ambient noise and personal noise exposure exceeded 85 dB(A) and 90 dB(A), respectively. Overall sound pressure levels generated by and passing through earphones reached 109 dB(A). The one-third octave band spectrum of the earphone noise during the shift exceeded 90 dB(SPL) in the range of 315-2000 Hz. The number of ears demonstrating a TTS, defined as a shift of 10 dB or more in postwork over prework hearing thresholds, was significantly greater at 1500 and 2000 Hz among ears with earphones (P < 0.05 and P < 0.01, respectively) compared to those without. The reverse was observed at 4000 Hz for ears without earphones (P < 0.01). Workers wearing earphones or headsets as communication devices in noisy environments are exposed to high risk of hearing loss, particularly at the frequencies of 1500 and 2000 Hz. Ideally, hearing conservation programs for such workers should account for potential hearing losses at frequencies of 2000 Hz or lower frequencies induced by amplified voice signals.

Earplug-Type Earphone with Built-in Microphone Improves Monosyllable Intelligibility in Noisy Environments

Received Jul 18, 2007; Accepted Dec 7, 2007 Correspondence to: T. Nakao, Department of Health Policy and Management, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan, 1–1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan (e-mail: t-nakao@med.uoeh-u.ac.jp) Earplug-Type Earphone with Built-in Microphone Improves Monosyl lable Intelligibility in Noisy Environments

666 Challenges for the better screening of sleep apnea syndrome in a railway company in japan

Introduction SAS is known to cause drowsiness and lack of concentration at work and poses a serious job-fitness risk as a train driver. E company launched the initial screening program in 2003 using Epworth Sleepiness Scale (ESS) and induced pulse oximetry in 2007, and examin all train drivers every three years. Methods Ased on ESS and pulse oximetry the detailed examination using sleeping polysomnography (PSG). Crews who need medical treatment such as continuous positive airway pressure (CPAP) were subject to work restrictions until the improvement was confirmed. Results According to the statistics for 9 years until October 2016, 5500 crews examined 151 crews were subject to work restrictions. After treatment, more than 90% of the cases have recovered their AHI to less than 30% of previous level, and all drivers successfully returned to their original jobs in about 2 weeks. Discussions Arger proportion of SAS patients (2.7%) than average Japanese population (1.7%, Guidelines for Diagnosis and Treatment of Sleep Disordered Breathing in Cardiovascular Disease), company is still experiencing false negative cases improve the drivenvironment to prevent daytime drowsiness and educations for crew members.

841 People at elevated risk of developing heat-related illness at workplace: a case-control study

Introduction Primary causes of heat-related illness (HRI) at work are: extreme heat and humidity, heavy work load, continuous exertion and infrequent rest, clothes with poor vapor–permeability, and personal health condition. Empirical research has not been performed to investigate the effect of underlying health problems to HRI. Methods A case-control study was performed by asking occupational health staffs to report all HRI cases occurred at their workplaces in 2015 and 2016. One co-worker control of the same gender at the closest in age was also reported for each case. Target population included: 26 large manufacturing factories, 15 major construction companies, all traffic guard companies in Japan, and a fire stations in Kitakyushu city. Their results of the periodic health examination were collected to evaluate the underlying health problems of obesity (BMI >25), impaired glucose tolerance, IGT (HbA1c≥6.5%, fast blood sugar ≥126 mg/dL, and/or casual blood sugar ≥200 mg/dL), high blood pressure, HBP (≥140/90 mmHg), and dyslipidemia (LDL-C ≥140 mg/dL, HDL-C <40 mg/dL, or TG ≥150 mg/dL). Data were statistically compared between the case and the control using JMP Pro 13. Results Overall incidence rate of HRI at the examined workplaces was 0.065% (114 cases/1 76 094 person-year). A total of 102 pairs (n=204) could be compared. Cases showed higher BMI (p=0.046) and visceral circumference (p=0.045). Cases and controls included 12 and 2 persons with IGT, respectively (p=0.005). Multiple logistic regression analysis revealed increase of HbA1c elevated the risk of developing HRI (OR 16.76 [95% CI: 2.44 to 165.5], p=0.0014), whereas LDL-cholesterol showed protective effect (OR 0.97 [0.95–0.99], p<0.001). Conclusion Significantly elevated risk of developing heat-related illness was observed among workers with IGT. Impaired endothelium-dependent vasodilatation among workers with IGT may decrease heat dissipation by conduction, convection, radiation, and sweat evaporation and may pose a risk to develop HRI.

Evaluation of the improvement in hearing Japanese speech while wearing earplugs advertised as enabling communication

Workers often refuse to wear earplugs because of the difficulty hearing conversations in noisy workplaces. Little research has been performed to explore whether multiple syllables of the Japanese language are difficult to hear through earplugs. New earplugs recently became available that could be used to communicate clearly in noisy workplaces and simultaneously prevent personal noise exposure. This study aimed to evaluate the hearing of speech using three types of earplugs in a noisy environment. The subjects were 10 people without hearing loss. We conducted this experiment in the anechoic room at the University of Occupational and Environmental Health, Japan. We set up a pink noise environment at 80 dBA, 85 dBA, and 90 dBA, and evaluated the hearing of speech with and without earplugs. The subjects were asked to distinguish standard Japanese words comprising two syllables recorded on a CD-ROM (TY-89) established for the evaluation of the fitness of hearing aids. If the speech level required for 90% inte...

Introduction of a hearing conservation program in a Japanese enterprise

To prevent occupational hearing loss, the Ordinance of Industrial Safety and Health in Japan requires employers to measure sound levels in eight hazardous areas in the workplace. In addition, the Guidelines for the Prevention of Noise-Induced Impairments require employers to measure the sound levels in noisy workplaces or provide audiometric testing for employees exposed to occupational noise. However, measurement of personal noise exposure is not a legal requirement in Japan. The Japanese Working Environment Measurement Standards define how to measure occupational noise using a sound level meter (SLM). However, it is difficult to evaluate real noise exposure for employees who use a sound-emitting industrial tool. We measured this exposure using a dosimeter at a Japanese manufacturing enterprise producing transport machinery. The sound levels at some workshops that were evaluated as 85 dBA using a SLM were shown to be more than 90 dBA using a dosimeter. Following these results, we are introducing a Hearin...

Acoustic characteristics of respirators

In some workplaces, employees are obliged to wear a respirator to protect them from harmful substances. However, an acoustical problem with respirator design is that respirators diminish the voice. Frequency analysis of sound through respirators could help tackle the problems associated with this design. We used a mannequin with a loudspeaker attached to its mouth and emitting pink noise. We measured the noise with 59 combinations of respirators and filters. For half-face masks with one or two filters, attenuation of the noise under 1 kHz was relatively small. The attenuations over 1 kHz varied widely among the tested respirators. With full-face masks, the attenuated frequency was lower than with the half-face masks. Respirators with a speaking diaphragm conducted louder sound over 3 kHz than did respirators without a speaking diaphragm. Among disposable masks, the attenuations were smaller than with half-face masks. We discuss the requirements for smooth communication among workers using respirators in l...

Bacterial attachment and insertion loss of earplugs used for fixed periods in noisy workplaces

In noisy workplaces, employees often tend to use earplugs for a long time in Japan. We have previously reported conditions related to bacterial attachment and the insertion loss of earplugs using data collected from six companies. In the present study, we distributed different kinds of foam earplugs at five companies and collected them after 1-, 2-, 4-, and 8-week usage (n = 123). We examined the total viable counts and presence of Staphylococcus aureus using 3M Petrifilm. We evaluated the insertion losses by means of the GRAS 45CB Acoustic Test Fixture. We detected a large number of viable counts in 5% of the earplugs. We found Staphylococcus aureus in 7% of the earplugs. We observed a small deterioration in insertion loss after 8-week usage. Neither the condition of bacterial attachment nor the insertion loss correlated with duration of use. We discuss the proper usage of earplugs in terms of industrial health.

Effectiveness of personal noise exposure measurement in the noisy workplace

In Japan, the Working Environment Measurement Standards require employers to measure noise of working environment by two kinds of methods using a sound level meter (SLM) once every 6 months. A-Sampling method is to be measured equivalent continuous sound level for at least 10 min. B-Sampling method is to be performed close to workers at times when the sound level appeared highest. We perform the risk assessment based on the values of the field measurement. In the East Japan Railway Company, workers move around several workshops and use hand tools. Therefore, it is difficult to estimate the personal noise exposure using only an SLM. To compare dose measurement with the Japanese field measurement, we carried out dose measurements for inspection or repair workers using a Personal Noise Dose Meter (Type 4448; Bruel & Kjaer). The results revealed that all sound levels using a dosimeter were less than 85 dBA, while the sound levels using an SLM were more than 90 dBA. In this case, the risk can be overestimated. ...