Kazuyuki Iwakiri

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.

Musculoskeletal pain and night-shift naps in nursing home care workers

BACKGROUND Care workers in nursing homes are at high risk of developing musculoskeletal disorders (MSDs). Many care workers work in shifts, which may compromise both the quality of care they give and their working life. Taking a nap during night shifts has been proposed to ameliorate shift work-related problems, but its relationship with MSDs is not clear. AIMS To explore how MSD pain differs according to frequency of night-shift naps. METHODS A questionnaire study was conducted on 111 care workers at three nursing homes. Of 98 respondents, data from 66 shift workers (54 women) were analysed. Data on self-rated pain in multiple sites (neck, shoulder, arm, leg and low back), naps during night shifts and relevant variables were collected. Participants were categorized into three groups on the basis of frequency of night-shift naps taken during the previous month: non-nappers, <50% nappers and >or =50% nappers. RESULTS Pain at all sites, with the exception of low back pain, differed significantly among the three groups. Pain scores were lowest at the arm and leg for the > or =50% nappers. Neck and shoulder pain was lower for the > or =50% nappers and the non-nappers compared to the <50% nappers. CONCLUSIONS Reduced pain in the arm and leg was associated with taking a nap at least once every two night shifts among the nursing home care workers. No association was found between low back pain and night-shift naps in this sample.

Effect of mental processing on low back load while lifting an object.

Study Design. Biomechanical study using a 3D motion analysis system conducted in a laboratory setting. Objective. To determine the effect of mental processing on low back load during lifting. Summary of Background Data. In addition to ergonomic factors such as frequent lifting, work-related psychosocial factors are significant in the onset of disabling back pain. Although the ergonomic effects on low back load while lifting have been investigated and are widely accepted in the workplace, few studies have investigated the effect of psychosocial factors on low back load while lifting. Methods. Thirteen healthy subjects lifted a box from the ground in 4 different lifting tasks in randomized order: (1) squat posture with knees flexed; (2) stoop posture with knees extended; (3) squat posture with mental processing using arithmetic tasks; and (4) stoop posture with mental processing using arithmetic tasks. We used a 3D motion analysis system and 4 force plates to record kinematic and kinetic data. We calculated dynamic triaxial low back joint moments and low back compression force as index parameters of low back load under these experimental conditions. Results. Mental processing significantly increased peak low back compression force and low back extension moment, but not lateral flexion or rotation moment, while lifting in both lifting postures. Also, mental processing increased trunk bending angles in the squat posture. Although a tendency for decreased pelvic forward tilt was observed, mental processing did not significantly decrease forward pelvic tilt in the stoop posture. Conclusion. Mental processing during lifting tasks seems to affect both trunk and pelvis angles in the sagittal plane for squat and stoop postures, resulting in increased low back load. The present findings might help explain the effect of ergonomic demands of lifting tasks as well as psychosocial factors responsible for the onset of disabling back pain. Level of Evidence: 2

Positive emotion inducement modulates cardiovascular responses caused by mental work

BackgroundPositive emotion is considered as an important factor related to health-relevant biological processes, including cardiovascular responses. To explore the possibility of using positive emotion as a tool to manage cardiovascular response of white-collar workers, we examined the influence on cardiovascular response of positive emotion inducement before a mental work.MethodSeventeen healthy males participated and performed a 10-min, PC-based Stroop color word task as their mental work. Before the task, 60 pleasant pictures chosen from the International Affective Picture System were presented in a random order under a positive emotion inducement condition while a gray screen was presented under a control condition. A 30-min relaxation period after completing the task was provided to examine the aftereffects of positive emotion inducement. Throughout these periods, systolic and diastolic blood pressure, mean arterial blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured continuously.ResultsBlood pressure and total peripheral resistance were lower during the picture presentation period under the positive emotion inducement period compared to the control condition. All indices did not differ during the color word task period. During the relaxation period after the task, however, blood pressure and total peripheral resistance were lower under the positive emotion inducement condition compared to the control condition.ConclusionPositive emotion inducement before a mental work beneficially modulates cardiovascular responses, suggesting that positive emotion inducement may be a useful tool to manage the cardiovascular response to mental work.

White-collar workers’ hemodynamic responses during working hours

In the present study, two investigations were conducted at a communication center, to examine white-collar workers’ hemodynamic responses during working hours. In investigation I, hemodynamic responses were measured on a working day; and in investigation II, cardiovascular responses were verified on both working and non-working days. In investigation I, blood pressure, cardiac output, heart rate, stroke volume, and total peripheral resistance were measured in 15 workers during working hours (from 9:00 am to 18:00 pm) on one working day. Another 40 workers from the same workplace participated in investigation II, in which blood pressure and heart rate were measured between the time workers arose in the morning until they went to bed on 5 working days and 2 non-working days. The results showed that blood pressure increased and remained at the same level during working hours. The underlying hemodynamics of maintaining blood pressure, however, changed between the morning and the afternoon on working days. Cardiac responses increased in the afternoon, suggesting that cardiac burdens increase in the afternoon on working days. The present study suggested that taking underlying hemodynamic response into consideration is important for managing the work-related cardiovascular burden of white-collar workers.

Low back pain among workers in care facilities for the elderly after introducing welfare equipment.

OBJECTIVE The purpose of this study was to clarify the causes of low back pain among workers in care facilities for the elderly after the introduction of welfare equipment. METHODS We conducted anonymous questionnaire surveys among administrators and care workers in eight elderly care facilities. The questionnaires were designed to investigate the status of both the care workers and facility. In reference to the care facility, the questionnaires were comprised items for investigating basic information, occupational safety, and health activities. For care workers, in addition to basic information, occupational safety, and health activities, the questionnaires also comprised items for investigating resident transfer and bathing methods, low back pain, and occupational stress. RESULTS Completed questionnaires were returned by eight care facility administrators (response rate: 100%) and 373 care workers (response rate: 92.3%), among which 367 were used for analyses. Many care workers participated in a variety of occupational safety and health activities that were conducted in the facilities. Various types of welfare equipment were introduced into the care facilities and subsequently used by many care workers during resident transfer and bathing. As a result, 89.9% of the care workers reported having only slight or no low back pain. The remaining 10.1% reported having serious low back pain that interfered with their work. On the basis of logistic regression analysis, low back pain was associated with the following variables: failure to provide the appropriate method of care to each resident, failure of colleagues to discuss methods for improving care, lack of instructions regarding the use of welfare equipment, and inappropriate job rotation. An association was also found between low back pain and poor posture, poor resident-lifting technique, insufficient time to complete work, and a shortage of workers to assist with resident transfer or bathing. CONCLUSION Although care workers received instructions on the health and safety activities extracted from the surveys, an association was still found between these activities and low back pain. This was thought to result from some care workers not establishing the appropriate method of care for each resident, not discussing methods for improving care with other colleagues, not using the welfare equipment, and failing to practice appropriate job rotation. These results suggest that low back pain among care workers in the facilities for the elderly that have introduced welfare equipment is caused by a failure to sufficiently conduct appropriate care methods.

Biomechanical analysis of low back load when sneezing

BACKGROUND Although sneezing is known to induce low back pain, there is no objective data of the load generated when sneezing. Moreover, the approaches often recommended for reducing low back pain, such as leaning with both hands against a wall, are not supported by objective evidence. METHODS Participants were 12 healthy young men (mean age 23.25 ± 1.54 years) with no history of spinal column pain or low back pain. Measurements were taken using a three-dimensional motion capture system and surface electromyograms in three experimental conditions: normal for sneezing, characterized by forward trunk inclination; stand, in which the body was deliberately maintained in an upright posture when sneezing; and table, in which the participants leaned with both hands on a table when sneezing. We analyzed and compared the intervertebral disk compressive force, low back moment, ground reaction force, trunk inclination angle, and co-contraction of the rectus abdominis and erector spinae muscles in the three conditions. FINDINGS The intervertebral disk compressive force and ground reaction force were significantly lower in the stand and table conditions than in the normal condition. The co-contraction index value was significantly higher in the stand condition than in the normal and table conditions. INTERPRETATION When sneezing, body posture in the stand or table condition can reduce load on the low back compared with body posture in the normal sneezing condition. Thus, placing both hands on a table or otherwise maintaining an upright body posture appears to be beneficial for reducing low back load when sneezing.

Effectiveness of re-education based on appropriate care methods using welfare equipment on the prevention of low back pain among care workers: a 1.5 year follow-up study

Many care workers at elderly care facilities in Japan suffer occupational low back pain (LBP) despite the utilization of welfare equipment. When introducing welfare equipment such as hoists and sliding boards, education on appropriate care methods using welfare equipment is usually conducted, but the effect of education diminishes with time. This intervention study aimed to examine the effect of re-education on appropriate care methods using welfare equipment on the prevention of care workers’ LBP at an elderly care facility. At the intervention facility, 49 care workers were enrolled in ergonomic education program for 1.5 yr in order to improve care methods using welfare equipment. At the non-intervention facility, 33 care workers were not enrolled in the program. Rates of severe LBP were not significantly different between the facilities. However, during the study period, the rate of severe LBP among care workers did not increase at the intervention facility, while it doubled among care workers at the non-intervention facility. The care workers at the intervention facility showed improvement in care methods using welfare equipment during the study period. Hence, we think that re-education regarding appropriate care methods using welfare equipment has the potential to prevent exacerbation of LBP.