Validity and reliability of Japanese version of the MAPO index for assessing manual patient handling in nursing homes.

OBJECTIVES: Low back pain (LBP) among caregivers in Japanese nursing homes has long been considered an occupational health issue. This study aimed to verify the reliability and validity of our developed Japanese version of the Movement and Assistance for Hospitalized Patients (J-MAPO) index, a risk assessment tool for LBP, in nursing homes. METHODS: Two inspectors assessed 15 nursing homes using J-MAPO, and deduced 3 LBP risk levels as follows: low, moderate, and high risk. Caregivers in nursing homes responded to a self-administered questionnaire on LBP over the past 12 months. Data from 296 caregivers with no missing data were used. We further used logistic regression models to analyze the association between LBP as a dependent variable, and J-MAPO risk level as an independent variable. We used Cohen kappa coefficient to assess interrater reliability to further assess the agreement between the 2 inspectors. RESULTS: The multivariate logistic regression analysis showed that the adjusted odds ratio and 95% CIs for LBP increased progressively with J-MAPO risk level (Low-risk: 1.00; Moderate-risk: 1.70 [0.74-3.91]; High-risk: 2.67 [1.28-5.56]). Furthermore, the J-MAPO risk levels assessed by the 2 inspectors were in perfect agreement (κ = 1) observed for interrater reliability using Cohen kappa coefficient. CONCLUSIONS: There was high interrater reliability, and J-MAPO risk levels were associated with LBP. Therefore, our results suggest that the J-MAPO is a useful risk assessment tool for LBP in Japanese nursing homes.

Lifestyle and subjective musculoskeletal symptoms in young male Japanese workers: A 16-year retrospective cohort study.

This longitudinal study was conducted from 2002 to 2018 and aimed to investigate predictive lifestyle factors for the occurrence of subjective musculoskeletal symptoms. The participants came from several employers in Japan. Setting 2002 as the baseline, we performed logistic regression analyses using lifestyle questionnaire items as explanatory variables and Stiff neck/shoulders (SN/S) and Lower back pain (LBP) as objective variables (n = 16,748). Workers who responded positively to good lifestyle items with an odds ratio < 1.0 and those who did not were classified in the Good (GL) and Poor lifestyle groups (PL), respectively. The survival period between the groups was compared using the log-rank test and Cox hazard regression analysis with propensity score matching (n = 3,593). Based on the Cox hazard regression analysis results, the risk of SN/S was about 2.54 (95% confidence interval [CI]: 1.80-3.59) times higher for PL than for GL (p < 0.001). Similarly, after propensity score matching, the risk was about 2.33 (95% CI: 1.07-5.10) times higher for PL than for GL (p < 0.05). Further, LBP risk was about 2.45 (95% CI: 1.67-3.58) times higher for PL than for GL (p < 0.001). Similarly, after propensity score matching, the risk was about 3.50 (95% CI: 1.60-7.68) times higher for PL than for GL (p < 0.01). This study highlighted that workers with four good lifestyle factors (life satisfaction, hours of sleep, exercise habits, and physical fitness) presented reduced risk of subjective musculoskeletal symptom occurrence. To prevent musculoskeletal symptoms, physicians and occupational health staff should advise on workers' individual lifestyle.

[A case study of tailor-made exercise for preventing decrease in physical function: Analyzing the effect of tailor-made exercise from a motion study, motor function test, and questionnaire].

OBJECTIVE: This study aimed to verify the effect of tailor-made exercise depending on the characteristics of a certain food manufacturing industry on the physical function and subjective symptoms of employees. METHODS: For the development of tailor-made exercise, work analysis was carried out at each factory to comprehend the physical burden due to work load. The motor function test and questionnaire survey for subjective symptoms were conducted before and after exercise during 3 months. The motor function tests included the 30-s chair-stand test and two-step test. RESULTS: There were significant improvements in the 30-s chair-stand test after tailor-made exercise intervention for men and women (men: 20.9±4.8 vs 27.9±5.1 counts/30 s, p < 0.01; women: 19.4±3.1 vs 23.7±2.7 counts/30 s, p < 0.01) but not in the two-step test. In addition, as a result of comparing the questionnaire survey for subjective symptoms before and after intervention, there was a significant difference (p < 0.05) in "stumbling and staggering within 1 month," "feeling of fatigue in the back," "feeling of fatigue in the right foot/ankle," and "feeling of fatigue in the left foot/ankle." CONCLUSIONS: It is thought that the leg muscle strength increased due to tailor-made exercise, and the stumbling and staggering improved. In addition, feeling of fatigue in the back and in the right and left foot/ankle was improved. It was suggested that tailor-made exercise intervention can significantly affect the physical function of employees.

Decrease in Work Ability Index and sickness absence during the following year: a two-year follow-up study.

PURPOSE: Using a 2-year follow-up design, we examined whether changes in work ability during 1 year predicted sickness absence in the following year. METHODS: Workers (N = 1408) from the Japanese information technology sector each completed the Work Ability Index (WAI), the Brief Job Stress Questionnaire (BJSQ), and the General Health Questionnaire (GHQ) in 2011 and 2012. Absence data during 2013 was obtained from employees' computerized attendance records. We used psychological distress as evaluated by the GHQ; job stress and job support calculated using the BJSQ; and job title, sex, and age as potential confounding variables. RESULTS: Thirty-five employees had at least one sickness absence lasting more than seven consecutive days in 2013. Forty-nine percent of sickness absences were due to mental illness, and the others were due to orthopedic disease (20%), cancer (9%), and other illnesses (23%). Decrease in WAI scores from 2011 to 2012 predicted sickness absence in 2013 (Odds ratio (OR) 1.19, 95% confidence interval (CI) 1.12-1.27). This association remained unaltered after adjusting for sex, age, job title, WAI score from the year before, job stress, job support, and GHQ score (OR 1.15, 95% CI 1.06-1.25). We analyzed this association separately by reason for absence: mental or other illness. WAI score decreases predicted sickness absence for both reasons (OR for mental illness 1.24, 95% CI 1.14-1.36; OR for other illnesses 1.14, 95% CI 1.04-1.24). CONCLUSIONS: Decrease in work ability during the year predicts sickness absence in the following year while predictive power was weak.

Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study.

Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n=7) and the control group (n=6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

Sense of coherence modifies the effect of overtime work on mental health.

OBJECTIVES: In the occupational health field, it is important to know how workload influences mental health. Overtime work and job strain appear to affect the mental health status of workers. Sense of coherence (SOC) may mediate the relationship between work stress and mental health. Since SOC represents a personal ability to manage psychological stressors, we hypothesized that a strong SOC would modify the adverse effect of an objective measure of overtime work on mental health. METHODS: A total of 1,558 Japanese workers employed in an information technology company were asked to complete a 3-item SOC Questionnaire and 28-item General Health Questionnaire (GHQ) to assess mental health status. Workload was assessed by the actual amount of overtime work hours recorded by the company. RESULTS: Multiple regression analysis revealed a main effect of overtime work (ß=0.08, p=0.0003) and SOC scores (ß=0.41, p <0.0001) on GHQ scores. There was a tendency toward interaction between overtime work and SOC scores (ß=0.05, p=0.051). Simple slope analysis supported this association (-1 SD below the mean, simple slope=0.04, SE=0.01, p < 0.0001; +1 SD above the mean, simple slope=0.01, SE=0.01, p=0.188). CONCLUSIONS: These results suggest that SOC buffers the mental health impacts of workload as measured by an objective index of overtime work, and should be considered when assessing the effects of workload on mental health.

Work improvement factors for the amelioration of work ability, with a focus on individual capacity to deal with stress in an IT company.

The aim of this study was to explore factors that ameliorate work ability by focusing on workers' capacity to deal with stress.The subjects were 1,330 workers from the Japanese information technology (IT) sector. Each subject completed questionnaires in 2011 and 2012 that consisted of the work ability index (WAI), the three-item sense of coherence (SOC), and the Mental Health Improvement and Reinforcement Research of Recognition (MIRROR). The results of the WAI were also obtained in 2013. The median SOC score in 2011 was used to divide the subjects into two groups, the Low SOC group and the High SOC group, then we verified the factors that contributed to improved work ability in both of these groups over a two-year period. Results indicate that an improvement in work ability in the Low SOC group could be predicted by giving workers opportunities for education or training, by making efforts to reduce the stress of commuting, by clarifying their assignments, and by establishing support systems when troubles occur. For the High SOC group, such improvements could be predicted by giving workers job control, by giving education or training for the promotion of their abilities, and by establishing a system for assuming responsibility. In conclusion, improvements in the work environment can increase the work ability of Japanese IT workers in conformity with their capacity to deal with stress.

Visual recognition memory test performance was improved in older adults by extending encoding time and repeating test trials.

OBJECTIVES: The aim of this study was to investigate whether the combination of extension of the encoding time and repetition of a test trial would improve the visual recognition memory performance in older adults. METHODS: We evaluated visual memory performance in young and older adults on a Yes-No recognition memory test under four different conditions. The conditions consisted of combinations of encoding times of two and four seconds (E2 and E4) and first and second retrieval practice test trials (T1 and T2): E2T1, E2T2, E4T1 and E4T2. Performance was evaluated by measuring hit rates, false alarm rates, discrimination ability and response bias. RESULTS: Older adults showed better improvement of hit rate and discrimination ability under the E4T2 conditions whereas young adults showed better memory performance under the E2T2 conditions. CONCLUSIONS: A longer encoding time and repetition of the test was effective in improving the visual memory performance in terms of the hit rates and discrimination ability of older adults. The results suggest that this strategy should be useful in providing a suitable work environment for older workers.

The relationship between work ability and oxidative stress in Japanese workers.

Work ability is based on the balance between personal resources and work demand. This study focused on the personal resources component of work ability. The aims of this study were to elucidate the association between work ability and cardiovascular (CV) risk factors, particularly oxidative stress, and to estimate the effect of a community-implemented lifestyle modification programme on work ability and CV risk factors. Urinary 8-iso-prostaglandin F2α (PGF2α), a biomarker of oxidative stress, was negatively correlated with psychological resources, as measured by the Work Ability Index (WAI). Overall WAI score was unchanged following the programme, while CV risk factors and antioxidative activity improved. A reduction in PGF2α levels was correlated with an improvement in subjective work ability relative to job demands, as assessed by a WAI item. Taken together, the results suggest that lifestyle modification programmes enhance the personal resources component of work ability and are associated with a reduction in oxidative stress.

The effects of static trunk flexion on oxygenation and electromyographic activity of erector spinae muscles.

In the workplace, localized muscle fatigue can be a limiting factor for prolonged static work. It is important to study the etiology of fatigue in the muscle to prevent discomfort and potential muscle injury. The purpose of this study was to investigate the effect of sustained trunk flexion and loading on the erector spinae muscles (ESM) fatigue using electromyography (EMG) and muscle oxygenation (Mox) changes. Twelve healthy male volunteers, aged between 19 and 28 years (mean age 23 +/- 2.6), participated in this study. The subjects held a load (5, 10 and 15 kg) and no load in their hands whilst sustaining trunk flexion at 60 degrees and also in an upright standing posture for 30 seconds. Five minutes rest was given between the conditions, and each condition was randomly repeated three times. Surface EMG and near-infrared spectroscopy were recorded. Root mean square and median frequency (MF) of EMG, and Mox were calculated. The results showed a greater decrease in Mox with an increase in loads over time (P = 0.015). Using unloaded trunk flexion as a control to ascertain load effect resulted in a significant difference in Mox in the unloaded condition and in the 15 kg condition (P = 0.027). EMG results showed a significant decrease in the MF over time in trunk flexion while holding a load (P < 0.001). These results show objectively that trunk flexion while holding loads causes ESM fatigue.

Effects of menopausal hot flashes on mental workload.

This study examined the differences in psychophysiological responses during mental task performance between women with (Group S) and without (Group A) menopausal hot flashes. Twelve women who reported experiencing daily moderate or severe menopausal hot flashes (Group S) and twelve women who reported having no hot flashes (Group A) participated in a mental arithmetic (Task) and a control (Non-task) experiment that occurred twice during 30 min. Although Group S experienced frequent hot flashes during mental arithmetic task, no significant differences between the two groups emerged for the percentage of correct responses and reaction time, and cardiovascular and thermoregulatory responses. However, the STAI state anxiety score was significantly higher in Group S than in Group A during both rest and mental tasks, and stress-related cortisol secretion showed a tendency to increase in Group S compared with Group A after task. The present study indicates that there were no significant differences in physiological responses and cognitive performance between women with and without menopausal hot flashes during mental arithmetic, but women with menopausal hot flashes might perceive higher psychological stress during rest and mental arithmetic tasks than asymptomatic women.

Fatigue sensation, electromyographical and hemodynamic changes of low back muscles during repeated static contraction.

The effects of work strategy and a rest condition on the physiological changes of the erector spinae muscle were studied. Eleven volunteers repeated fatiguing static contractions of holding an industrial box in 30° trunk flexion for a repetition of 12 times interrupted by rests for which the duration was equal to the duration of each preceding contraction. Each contraction was stopped at two fatigue sensation levels; moderate or strong, which corresponded to Borg's CR-10 3 and 5, as the work strategy conditions. The repeated contractions were performed for a total of eight conditions combined with the two rest conditions, with and without stretch exercise, and two contraction levels of 10 and 40% maximum pulling force in flexed posture (MVC) on separate days. Near-infrared spectroscopy and surface electromyography (EMG) were recorded. Amplitude and median frequency (MF) of EMG, oxy-hemoglobin, and deoxy-hemoglobin were calculated. MF related to fatigue sensation most closely. Oxy-hemoglobin decreased during each contraction. It, however, increased with repetition especially at 10% MVC and the increase was interpreted as adaptation to the work. The effect of the work strategy and the rest conditions was weak. MF decreased more in a strong work strategy condition than in a moderate one.

Kaizen: ergonomics approach to occupational health and safety.

Kaizen (work improvement) is the forte of Japanese industry. Kaizen activities were born in the early 20th century under the name efficiency research. These activities were the beginning of industrial engineering (IE). Later on people began to rethink the single-minded devotion to improving productivity. Then the job re-design concept was developed. The main target of kaizen in the area of occupational health and safety in Japanese manufacturing is the improvement of inadequate working posture followed by the improvement of work for transporting and lifting heavy objects. Unfortunately, the kaizen activities undertaken by most Japanese companies are still focused on improving productivity and quality. The know-how for promoting kaizen activities that integrate the three aspects of IE, occupational health, and ergonomics is not being accumulated, however. In particular, the IE techniques should be incorporated into kaizen activities aimed at occupational safety and health, and the quantitative assessment of workload is required. In addition, it is important for on-the-job kaizen training in the ERGOMA Approach for production supervisors, who are the main advocates of IE kaizen.

Perceived demands and musculoskeletal disorders in operating room nurses of Shiraz city hospitals.

Excessive demands on Operation Room (OR) nurses may result in high rates of Musculoskeletal Disorders (MSDs). This study was conducted among Shiraz city hospital OR nurses to determine the prevalence of MSDs and to examine the relationship between perceived demands and reported MSDs. In this cross-sectional study, 375 OR nurses participated (response rate: 80%). The Nordic Musculoskeletal Disorders Questionnaire and the Job Content Questionnaire were used as collecting data tools. Lower back symptoms were found to be the most prevalent problem in the OR nurses studied with a past year prevalence of 60.6%. Perceived physical demands were significantly associated with musculoskeletal symptoms (odds ratio ranged from 2.04 to 7.24). Manual material handling (MMH) activities were most frequently associated with reported symptoms. Association was also found between perceived psychological demands and reported symptoms (odds ratio>1.68). Based on the findings of this study, it could be concluded that operation room was not only a physically but also psychologically demanding environment. Any interventional program for preventing or reducing MSDs among OR nurses had to focus on reducing physical demands, particularly excessive MMH demands as well as considering psychological aspect of working environment.

[Influence of physical workload patterns and breaks on heart rate recovery].

It is necessary to try to achieve quick recovery from work strain by setting adequate breaks and shortening continuous working hours to prevent the accumulation of fatigue. However, there has been no research investigating the influence of the timing and lengths of breaks on individual aerobic capacities in recovery from work strain. In this study, we set three load patterns based on the length and timing of breaks: "no breaks", "one break" and "regular small breaks". We examined the differences of the heart rate variation in the recovery time after working considering the individual aerobic capacities (VO(2)max) of ten male subjects (mean age 22.3 +/- 1.7 yr) in the case of 50 W or 100 W workloads on a bicycle ergometer. When individual aerobic capacity was not considered, the "regular small breaks" condition led to the quickest recovery to the level of the resting heart rate at 50 W workload. Not all conditions showed heart rate recovery within 30 min at 100 W workload. On the other hand, when individual aerobic capacity was considered, the "regular small breaks" condition showed the quickest recovery to the level of the resting heart rate at 50 W workload in the low aerobic capacity group (VO(2)max mean 42.2 +/- 3.7 ml/kg/min). However, in the high aerobic capacity group (VO(2)max mean 54.5 +/- 4.1 ml/kg/min), the "regular small breaks" condition resulted in the quickest recovery of the level to the resting heart rate at 100W workload. Two-way repeated measures ANOVA was performed for the recovery time with respect to the rate of increase from resting heart rate to examine the influence on heart rate recovery of physical activity loads, workload patterns and individual fitness. Physical activity loads were strongly related to the increase from resting heart rate in recovery time, and workload patterns showed that the regular small breaks condition was related to the heart rate recovery in the high fitness subjects in the case of the exercise intensity of 100 W. The effect of work strain decreased by workload patterns was defined by the relationship between physical activity load and individual fitness. In future occupational health activities, it will be important to manage work in order to aim for quick recovery from work strain by using ergonomics. The evaluation of the level of the physical activity load and distribution of proper break times during working in addition to individual aerobic capacities are important in considerations of quick recovery from work strain.

Effects of the menstrual cycle on language and visual working memory: a pilot study.

This study aimed to examine the effects on language and visual working memory of the follicle, luteal, and menstruation phases. The subjects were 12 female students. We added visual information and the assignment of experimental tasks, which requires the faculty of sight, to the previous study; therefore, this study has an index of visual and linguistic working memory. Computer-based tasks formulated by the authors, using the working memory that actively retains the information as the index, were used for experiments of 30 min during the follicle, luteal, and menstruation phases. After completion of the experiment of each phase, blood samples were collected in order to clearly distinguish the three phases of the subjects' menstrual cycle, and the session order was counter-balanced. The results showed that mental workload was higher in the luteal phase and stress was more easily felt. Indefinite complaints were most frequent during the menstruation phase, but task performance was good regardless of the indefinite complaint. It suggested that when the same tasks were performed during three phases, the sympathetic nerve was ascendant.

Effects of the menstrual cycle on working memory: comparison of postmenstrual and premenstrual phases.

This study aimed to examine the effects on working memory of the postmenstrual and premenstrual phases. The subjects were 12 female students. Computer-based tasks formulated by the authors, using the working memory that actively retains the information as the index, were used for experiments of 60 min during the premenstrual and postmenstrual phases. Session order was counter-balanced. The results showed that there was a significantly lower error rate for working memory tasks in the premenstrual phase, suggesting that task performance was good. Mild premenstrual symptoms had no effect on working memory function of the premenstrual phase. Further, no clear difference in terms of phase was found for mental workload or change in heart rate variability, which are used to evaluate workload. For this reason, the estrogen sex hormone secreted from the ovaries in relation to the menstrual cycle is thought to be involved in the working memory function rather than the indefinite menstrual complaint.

Mental workload under time pressure can trigger frequent hot flashes in menopausal women.

The aim of this study is to examine the relationship between mental workload and occurrence of hot flashes. Twelve women with moderate to severe menopausal hot flashes participated in the study. Subjects participated in both a mental arithmetic task (Task) and control (Non-task) experiments. We measured heart rate, heart rate variability, blood pressure, near infrared spectroscopy, skin temperature, and skin potential level. The incidence of hot flashes was greater in Task than in Non-task. No significant differences between before, during and after hot flashes emerged for the percentage of correct responses and reaction time. However, the percentage of correct responses for two subjects among the ten who experienced hot flashes in Task substantially declined during hot flashes. Chest skin temperatures increased in both Task and Non-task during hot flashes, and regional oxygen saturation was significantly higher in Non-task than in Task. The present study suggested that mental workload under time pressure might be a risk factor for menopausal hot flashes, and the performance of most people who experienced hot flashes was not affected by hot flashes, however, work-related difficulties due to cognitive disturbance during hot flashes might arise in some people.

Quantitative overload: a source of stress in data-entry VDT work induced by time pressure and work difficulty.

It is hypothesized that quantitative overload impacts psycho-physiological attributes of data-entry operators, although previous research has focused primarily on different aspects of VDT work, such as working time and environment, work station, keyboards and so forth. The objective of this study was to examine the influence on psycho-physiological responses of time pressure, task demand and their combined effect as underlying causes of quantitative overload while typing. A total of 12 subjects completed four 1-h typing tasks representing two levels of time pressure and task demand. Levels were manipulated by requiring participants to achieve a least number of character strings during each block, and by changing the number of letters in the character strings. Outcomes were measured in subjective assessment of workload, performance-related and physiological measures. Overall, increased time pressure increased perceived workload, productivity rate and heart rate, and decreased initial response time and typing duration. However, increased task demand increased error rate and initial response time with no change in heart rate. Heart rate variability did not indicate increased levels of time pressure or task demand. Quantitative overload as a consequence of time pressure and task demand influenced the subjective and psycho-physiological measures of data-entry operators to some extent.

Evaluating work ability and quality of life for clinical nurses in Taiwan.

This study investigated the work ability and its relationship with quality of life for the clinical nurses in Taiwan. The survey was of 1534 nursing professionals from 8 different hospitals. Work ability of nursing professionals varied by age, work experience, working departments and hospital types. Work ability of nurses increased with age until after the age of 45. Personal health condition and physical workload were the main factors contributing to the decline of the perceived work ability for senior nurses. For young nurses, the mental demands of work were a critical influence on their work ability. Moreover, work ability of nurses varied among hospital type and department. The work ability of nurses was strongly associated with the quality and safety of the work environment and leisure time management. For improving and maintaining the work ability of nurses, countermeasures such as enhancing the ability to cope with the job's mental demands for young nurses, and improving the job design to reduce physical workload for senior nurses are recommended.