Work-related musculoskeletal pain among physical therapists: A cross-sectional study in Kyoto and Shiga Prefectures, Japan.

OBJECTIVES: This study aimed to determine the actual working conditions and prevalence of musculoskeletal pain among physical therapists in Japan, and the risk factors associated with low back pain (LBP) and upper limb pain (ULP). METHODS: A cross-sectional study of physical therapists in the Kyoto and Shiga Prefectures was conducted using a self-administered questionnaire. The survey contents included questions regarding personal, work-related, and musculoskeletal pain factors. Logistic regression models were used to analyze factors associated with LBP and ULP. RESULTS: Responses from 1,479 participants were included in the analyses. The prevalence of LBP at the time of the survey and in the past one year was 40.1% and 74.3% in female, and 37.8% and 69.9% in male, respectively. The prevalence of ULP was 34.8% and 64.2% in female, and 27.2% and 53.3% in male. The number of patients who performed manual therapy per day, worked using a fixed-height bed, performed manual therapy, had job dissatisfaction and stress, were over 40 years old, and slept less than 6 hours were associated with LBP and ULP. Assistance task was a risk factor only for LBP, and female only for ULP. CONCLUSIONS: The prevalence of LBP and ULP among physical therapists in Japan was as high as that in nurses and care workers. Work-related factors associated with LBP and ULP were identified among physical therapists. Thus, to prevent work-related musculoskeletal disorders, measures to reduce the physical burden from the perspective of occupational health are required.

HIV/AIDS knowledge level, awareness of public health centers and related factors: a cross-sectional study among Brazilians in Japan.

BACKGROUND: Accurate information is essential so that HIV infection can be detected in time for initiation of HIV/AIDS treatment. Immigrants are at high risk for delayed HIV testing and diagnosis, but foreign residents in Japan also seem to face barriers to accessing HIV/AIDS care. We aimed to assess their knowledge level of HIV/AIDS and awareness of public health centers in Japan (PHCs), and to explore factors related to these items. METHODS: We conducted a cross-sectional study of Brazilians, the largest group of foreigners living in Shiga, using an anonymous, self-administered questionnaire survey in Brazilian Portuguese and Japanese via the Internet and mail. A multiple logistic regression analysis was used to examine the factors related to "Knowledge of HIV/AIDS" and "Awareness of PHCs". RESULTS: A total 182 Brazilians responded. More than half of them were beginners in Japanese. Most respondents were familiar with HIV/AIDS, but only 58% knew the existence of PHCs, and only 25% knew that HIV testing is available at PHCs free of charge and anonymously. A multiple logistic regression analysis showed that PHCs were less recognized by those with intermediate (odds ratio: 5.70, 95% confidence interval: 1.53-21.23) and beginner (odds ratio: 6.81, 95% confidence interval: 1.98-23.45) Japanese proficiency than by those with advanced. CONCLUSIONS: This survey revealed the knowledge level of HIV/AIDS and awareness of PHC among Brazilians in Shiga. Their lack of awareness of PHCs due to language barriers may lead to delays in HIV testing among them. Therefore, it is important for PHCs to disseminate information about medical services related to HIV/AIDS in Portuguese and plain Japanese to facilitate their access to HIV testing. However, PHC efforts alone are not enough. Medical interpreters who are familiar with Brazilian culture and customs, and the clinics that employ them, could help the Brazilian community and PHCs to overcome the language barrier and provide efficient and appropriate medical care to Brazilians. This would be one way to eliminate delays in HIV testing for Brazilians in Shiga.

Effects of different bed heights on the physical burden of physiotherapists during manual therapy: an experimental study.

This study aimed to determine the effect of physiotherapists' physical burden caused by different bed heights during manual therapy. Thirty-three male physiotherapists performed tasks simulating lumbar massage and passive hip abduction range-of-motion exercise (ROM) on the beds with low height (LH) and adjusted height (AH), with each task performed three times. The anterior inclination angle of the physiotherapist's trunk was measured, the surface electromyograms of the erector spinae and trapezius muscles were recorded, and perceived stress was assessed. The indexes obtained were statistically compared for different bed heights. Additionally, the lumbar disc compression force and flexion torque were estimated. The lumbar burden caused by the excessive bending and the biomechanical burden and perceived stress were stronger at LH than AH. In ROM tasks using the right hand, the muscle activity was lower at the left lumbar region at LH than at AH. At LH, the anterior inclination angle increased and the lumbar muscle activity declined as the number of tasks increased. The burden on the shoulders was not significantly different by bed heights. Our results showed that, when physiotherapists perform manual therapy, it is necessary to adjust the bed height to reduce physical burden and ensure higher quality of service.

Fraction and Number of Unemployed Associated with Self-Reported Low Back Pain: A Nation-Wide Cross-Sectional Study in Japan.

This study examined a cross-sectional association between self-reported low back pain (LBP) and unemployment among working-age people, and estimated the impact of self-reported LBP on unemployment. We used anonymized data from a nationally representative survey (24,854 men and 26,549 women aged 20-64 years). The generalized estimating equations of the multivariable Poisson regression models stratified by gender were used to estimate the adjusted prevalence ratio (PR) and 95% confidence interval (CI) for unemployment. The population attributable fraction (PAF) was calculated using Levin's method, with the substitution method for 95% CI estimation. The prevalence of self-reported LBP was 9.0% in men and 11.1% in women. The prevalence of unemployment was 9.3% in men and 31.7% in women. After adjusting for age, socio-economic status, lifestyle habits, and comorbidities, the PR (95% CI) for the unemployment of the LBP group was 1.32 (1.19-1.47) in men and 1.01 (0.96-1.07) in women, compared with the respective non-LBP group. The PAF (95% CI) of unemployment associated with self-reported LBP was 2.8% (1.6%, 4.2%) in men. Because the total population of Japanese men aged 20-64 in 2013 was 36,851 thousand, it was estimated that unemployment in 1037 thousand of the Japanese male working population was LBP-related.

A field study of exposure to whole-body vibration due to agricultural machines in a full-time rice farmer over one year.

OBJECTIVES: The aims of this study were to clarify in detail the levels of whole-body vibration (WBV) exposure from a variety of agricultural machines in a rice farmer over one year, and to evaluate the daily level of exposure compared with European and Japanese threshold limits. METHODS: The subject was a full-time, male rice farmer. We measured vibration accelerations on the seat pan and at the seat base of four tractors with various implements attached, one rice-planting machine, two combine harvesters, produced by the same manufacturer, and one truck used for transportation of agricultural machines. The position and velocity of the machines were recorded in parallel with WBV measurements. In addition, during the year starting in April 2010, the subject completed a questionnaire regarding his work (date, place, content, hours worked, machines used). We calculated the daily exposure to WBV, A(8), on all the days on which the subject used the agricultural machines. RESULTS: The WBV magnitude in farm fields was relatively high during tasks with high velocity and heavy mechanical load on the machine, and had no dominant axis. The subject worked for 159 days using the agricultural machines during the year, and the proportion of days on which A(8) values exceeded the thresholds was 90% for the Japan occupational exposure limit and 24% for the EU exposure action value. CONCLUSIONS: Our findings emphasize the need for rice farmers to have health management strategies suited to the farming seasons and measures to reduce WBV exposure during each farm task.

A field study on the physiological workload of garbage collectors in the Japanese summer.

A field study designed to reveal the physiological workload on garbage collectors (GC) was conducted in Japan. Three drivers who only operated a garbage truck, three loaders who actually collected as a team, three solo collectors, and one clerical worker, totaling 10 male workers participated in this study. The ambient temperature and the relative humidity, activity intensity, and heart rate were measured on the three days in July. The mean heart rate of the workers, excluding the clerical worker, was 97.5 bpm. There were cases in which the heart rate limit, as defined by ACGIH, was exceeded, including a case in which the loader sustainably exceeded this limit for over an hour. There were 10 worker-days in which the 58%HRmax level (corresponding to the permissible limit specified in the Netherlands) was exceeded based on the findings of the 18 worker-days for the loaders and solo collectors. There were many cases in which the energetic load of GC in the humid summertime in Japan exceeded the permissible limits as established in the U.S.A. and the Netherlands. The careful inspection of the actual work conditions and improvements in the work environment should be implemented for the occupational safety and health of GC.

A case of cervico-brachial disorder due to tactile interpretation for deaf-blind persons.

OBJECTIVES: We herein report a case of cervico-brachial disorder (CBD) due to long-term tactile interpreting. METHODS: The patient was interviewed to investigate her past history, occupational history, work conditions and clinical course in detail. The case was diagnosed in accordance with the "Diagnostic Criteria for CBD 2007" established by the Research Association for CBD of the Japanese Society for Occupational Health. RESULTS: The patient was a 49-year-old female who has worked as a regular occupational instructor at a welfare work activity center for deaf people since April 22, 2010. Her primary job is to instruct and aid others in learning confectionery manufacturing and coffee shop tasks. She also performs tactile interpreting for two deaf-blind workers during a morning health check and during any meetings. On September 3, 2010, she interpreted by tactile signing for about three hours alone during a meeting, due to the absence of other interpreters. She developed severe pain in her back immediately after carrying out this interpretation, and the pain thereafter continued and developed in the upper extremities. She was diagnosed with a severe and prolonged case of the non-specific type of CBD. DISCUSSION: Interpretation by tactile signing may impose a heavier burden on the upper extremities, shoulders and neck than that imposed by common sign language. A shorter time of interpretation, ensuring the availability of rest time and supporting tools or methods for the upper extremities, are therefore considered to be necessary to prevent the incidence of CBD among interpreters using tactile signing.

Effectual points of view in occupational health management for persons with cerebral palsy --interventional case approach in VDT work--.

In our previous study, we elicited effectual points of view (POV) in occupational health management for visual display terminals (VDT) operators with disabilities. In order to validate the POV, two VDT operators with cerebral palsy newly-participated in our case study. Problems were ascertained, and in order to attempt to reduce the workload and improve operability, we performed intervention using ergonomic measures. Evaluations were conducted through observations of the equipment used and posture, as well as measurements of sitting pressure distribution and surface electromyogram. For Case 1 (a 33 yr-old male), a trunk support was introduced inside the armrest of his chair to maintain the trunk in a comfortable position. For Case 2 (a 21 yr-old female), in order to improve her unstable sitting position, we changed her chair and adjusted it to an appropriate desk height. For both cases, we confirmed improvements in posture, sitting pressure distribution, myoelectric potential or operability. We were able to confirm that "maintaining of a comfortable trunk" and "alleviation of excessive bending, extension, and curvature of the spinal column and joints" obtained from the previous study as POV in health management are also effective in the present interventional cases.

Sleeping and working hours of residents at a national university hospital in Japan.

This study aimed to examine the status of time spent working and sleeping by resident doctors before the introduction of the New Training System for Residents in Japan. A time-budget survey was conducted over a 4-wk period on 102 residents at the Shiga University of Medical Science Hospital, and the response rate among residents was 76% of a total of 2,722 person-days. The average number of hours spent sleeping was the lowest and spent in the hospital including commuting time was the highest in residents of the surgery department, at 4.4 h and 18.9 h, respectively. Forty percent of residents reported dozing off at work, with the incidence rate being highest in residents of the surgery department (0.7 times/person-day). Dozing appeared to occur in response to the lack of sleep and fatigue, since the same residents slept longer on nights before days they reported not dozing off than on nights before days when they did doze off. Strong correlations were observed between the number of sleeping and working hours and between working hours and the number of patients in a resident's care. In order to maintain high standards of training and to get sufficient sleep it is therefore necessary for residents to manage their work and the number of patients in their care.

Work schedule differences in sleep problems of nursing home caregivers.

Nursing home caregivers (n=775; 604 women; mean age 33.6 years) were studied to examine how work schedules affect their sleep. The shift group (n=536) worked under a rotating two-shift system (n=365), a rotating three-shift system (n=66), or other types of shifts (n=78). The non-shift group included 222 caregivers. Participants completed a questionnaire about working conditions, sleep problems, health, lifestyle, and demographic factors. The two-shift caregivers reported the highest levels of difficulty initiating sleep (DIS, 37.6%), insomnia symptoms (43.0%), and poor quality of sleep (24.9%) among the groups. Adjusted odds ratios for these problems were significantly greater for the two-shift caregivers than for non-shift counterparts: DIS (odds ratio 2.86, 95% confidence interval 1.57-5.20), insomnia symptoms (2.33, 1.36-4.02), and poor sleep quality (2.15, 1.09-4.22). Our data suggest that working under a rotating two-shift system, which has a longer night shift, is associated with an elevated risk of sleep problems for nursing home caregivers.

Effect of mental stress on hemoglobin dynamics in trapezius muscles.

We examined the effect of mental stress on hemoglobin concentrations in the trapezius muscles of 20 healthy, non-smoking women. The participants held their arms out horizontally (physical stimulus) while standing upright for 1 min with 5 min intervals of seated rest, or performed Stroop's Color Word Test (mental stimulus), or both simultaneously. We measured heart rate, muscle tissue hemoglobin (oxy-hemoglobin, OxyHb; deoxy-hemoglobin, DeoHb; total hemoglobin, TotHb) concentrations in, and obtained surface electromyograms from the right upper trapezius muscle. Changes in the hemoglobin concentration (DeltaOxyHb, DeltaDeoHb, DeltaTotHb) induced by physical and/or mental stimuli were calculated. Changes with physical stimulus alone were compared with those induced by physical plus mental stimuli using repeated measures ANOVA. The DeltaDeoHb with physical and mental stimuli was significantly lower (p=0.013) than that with the physical stimulus alone, whereas the DeltaOxyHb and the DeltaTotHb values did not significantly differ (p=0.281, p=0.230). This finding indicates that mental load affects DeltaDeoHb in the trapezius muscle. We think that mental stimulus might provoke a reduction in oxygen consumption by the trapezius muscle. Further investigations using a longer duration of physical and mental stimuli are required.

Neuro-physiological study in persons with cervico-brachial disorders.

OBJECTIVES: In order to clarify the involvement in the nervous system by cervico-brachial disorders (CBD), we performed neurophysiological tests on the peripheral nervous system (PNS) and the central nervous system (CNS) in patients with CBD, subclinicals and healthy controls. SUBJECTS AND METHODS: We employed antidromic sensory nerve conduction velocities (SCV) in the hands and fingers for PNS function and event-related potentials (P300) for CNS higher function. Subjects for SCV were 27 patients, 14 workers with sign and symptoms of CBD (subclinicals) and 22 controls. Subjects for P300 were 23 patients, 12 subclinicals and 10 healthy controls. CONCLUSIONS: In the PNS, since significant reduction SCV in the index finger among patients was observed, we could not find clear evidence of decrease of conduction function. In the CNS, since the latencies and amplitudes of auditory P300 among patients were significantly delayed and decreased, respectively, and the latencies significantly correlated with symptom score, it was suggested that the dysfunction of the cognition and memory function. However, further investigation is necessary to clarify the mechanism.

[Sleep survey of medical residents at a National University Hospital].

In order to ascertain the workload and lifestyle of medical residents prior to the introduction of a new medical resident training system, 102 residents at a national university hospital were monitored for four consecutive weeks to ascertain their life habits. Valid responses were obtained from 76% of the respondents for a total of 2,722 person days. It was found that the average length of sleep was 5.7 h on weekdays and 6.8 h on weekends. Of the 102 residents, 40% slept less than six hours a night and 17% slept less than five hours a night. The time spent sleeping was particularly short among surgical residents. Given that lack of sleep not only affects the health of the residents negatively, but also compromises the safety of medical care that they provide, the new medical residency training system will need to monitor and analyze the wellbeing, including sleep patterns, of medical residents.

[An experimental study on muscle tension reaction induced by voice among sign language interpreters].

The purpose of this study is to ascertain the incidence of cervicobrachial muscle tension induced by voice among sign language interpreters (SLIs). The analyzed subjects included 8 professional SLIs (Case group) who complained of pain in the cervicobrachial muscle when listening to others' talking and 8 other people who have not learned sign language (Control group). Matching sexes, ages, and smoking habits of the Case and the Control groups was carried out. Informed consent to participate in the study was obtained from all subjects. While subjects relaxed in a sitting position, surface electromyographies (EMGs) were recorded from the right and left trapezius muscles and biceps brachii muscles. During this time, all subjects had two listening tasks: to listen to lectures in Japanese and to listen to instrumental music. An inquiry about subjective symptoms was conducted just after each task. Root-mean-square (RMS) values per 100 ms in each of the tasks were calculated for analysis of surface EMG. An original criterion of judgment was that the threshold of RMS values was 3.8 microV, and its threshold continued for more than 1 s. The criterion was used and the muscle tension was confirmed. Results showed muscle tension in the trapezius muscles or the biceps brachii muscles among 5 of 8 subjects in the Case group, and in 1 of 8 in the Control group when listening to the lecture. 3 subjects in the Case group and none in the Control group showed muscle tension in the trapezius muscles when listening not to music but to the lecture. The differences between the Case and Control groups in these results were not statistically significant. Confirmed muscle tension in SLIs when listening to a Japanese lecture is probably induced by the Japanese voice. It is necessary to further investigate whether muscle tension is an acquired reaction from sign language interpreting or a pathological reaction. Listening to Japanese voices may contribute to muscular overload in SLIs so that it may be necessary for SLIs to relax their muscles during break times with an absence of Japanese voices.

[Evaluation of a swiveling seat to reduce the physical load on forklift drivers].

Many forklift drivers have musculoskeletal disorders such as low back pain related to poor work posture and whole-body vibration. With a forklift operator's seat capable of 45-degree swiveling, we evaluated the physical reduction in the load in 10 subjects working in a back-looking position by means of surface electromyography (EMG) and the angle of rotation of the trunk and neck regions. The amplitude of surface EMG on the trapezius, erector spinae, and latissimus dorsi muscles in looking back or maintaining a back-looking position decreased with a swiveling seat compared to the stationary seat. Nevertheless, there was little alleviation of the amplitude of surface EMG on the sternocleidomastoid muscle in maintaining a back-looking posture and no decrease in looking back. The angle of rotation of the trunk maintaining a back-looking position was decreased greatly with the swiveling seat, but no decrease in the rotation angle of the neck was seen. Our study suggests that a swiveling seat is effective in reducing the physical load on the forklift driver during back-looking operations, and this may lead to the prevention of low back pain.

Work-related reproductive, musculoskeletal and mental disorders among working women--history, current issues and future research directions.

According to the recent changes of working environments and socio-economical conditions, the proportion of working women are increasing in Japan. Characteristics of occupational workload and stress of Japanese working women are consistent with those in many industrialized countries except man-dominant culture. In this review we describe the history, current issues, and future research directions on occupational health of working women, especially focused on reproductive health, work-related musculo-skeletal disorders (WMSDs), and mental disorders. In the reproductive health survey, traditionally main concern was about pregnancy outcomes, then fecundity studies, such as time to pregnancy, became topics recently. Future research will be shifted to outcomes not only during pregnancy but also disorders of hormonal balance and climacterium or health conditions after menopause. WMSDs are reviewed on mainly gender difference and its causative factors. Historically, mental health of working women in Japan has focused on the job stress of nurses. We compare results with a lot of recent researches in Europe and U.S.A., where interaction between occupational stress and family roles were studied. It is not easy to predict the prospective status of female workers in Japan, but social, workplace and familial supports will enhance their health promotion.