Hand-Arm Vibration Syndrome (HAVS) is caused by hand-transmitted vibration in industrial workers. Current ISO guidelines (ISO 5349) might underestimate vascular injury associated with range of vibration frequencies near resonance. A rat-tail model was used to investigate the effects of higher frequencies >100 Hz on early vascular damage. 13 Male Sprague-Dawley rats (250 ± 15 gm) were used. Rat-tails were vibrated at 125 Hz and 250 Hz (49 m/s2) for 1D, 5D and 10D; D=days (4 h/day). Structural damage of the ventral artery was quantified by vacuole count using Toluidine blue staining whereas biochemical changes were assessed by nitrotyrosine (NT) staining. The results were analyzed using one-way repeated measures mixed-model ANOVA at p<0.05 level of significance. The structural damage increased at 125 Hz causing significant number of vacuoles (40.62 ± 9.8) compared to control group (8.36 ± 2.49) and reduced at 250 Hz (12.33 ± 2.98) compared to control group (8.36 ± 2.49). However, the biochemical alterations (NT-signal) increased significantly for 125 Hz (143.35 ± 5.8 gray scale value, GSV) and for 250 Hz (155.8 ± 7.35 GSV) compared to the control group (101.7 ± 4.18 GSV). Our results demonstrate that vascular damage in the form of structural and bio chemical disruption is significant at 125 Hz and 250 Hz. Hence the current ISO guidelines might underestimate vascular damage at frequencies>100 Hz.
Ageing is associated with impaired working memory (WM) performance that may increase cardiovascular costs in older workers. Performance feedback (FB) was assumed to compensate for performance decline and reduce cardiovascular costs. Forty-eight younger (29 ± 3 yr) and 45 older (55 ± 4 yr) healthy workers had to perform a 0-back task (low WM load), 2-back task (high WM load) and 2-back task with FB (high WM load & FB). Age-related performance decline and enhanced blood pressure (BP) reactivity to WM load were found. The baroreflex sensitivity (BRS) decreased under high WM load in older workers compared to younger workers. The FB abolished age differences in omission rate and increased low frequency heart rate variability (HRV) in both age groups. Moreover, FB reduced heart rate in older workers and increased BRS as well as high frequency HRV in younger workers. The results suggest that older workers compensate for WM performance decline at cost of heightened BP due to age-related reductions of vagal tone and impairments of the baroreflex mechanism. The performance FB helps older workers to partly compensate for performance deficits and reduce cardiovascular costs by moderate decreases in sympathetic tone.
The aim of this study was to identify psychosocial work characteristics associated with long sick leave in a large population of male Japanese employees in multiple workplaces. We examined various psychosocial work characteristics (job overload, job control, supervisor support, coworker support, support by family and friends, role ambiguity, role conflict, intragroup conflict and intergroup conflict) of employees in six factories at the base line. We then conducted a follow-up survey on the recorded long sick leaves of ≥30 continuous days taken by the employees due to any medical condition. We found 574 cases of long sick leave out of 15,531 subjects during an average 5.07-yr follow-up. The results showed that high supervisor support was significantly associated with a decrease in the hazard ratio (HR) of long sick leave after adjustment for several confounding factors (95%CI; 0.69–0.97). High role ambiguity also tended to increase HR, but without reaching significance (95%CI; 0.99–1.41). The results suggest that supervisor support in the workplace may be important to reduce long sick leave in Japanese male employees.
We explored the associations of job strain with sleep and alertness of shift working female nurses and nursing assistants. Participants (n=95) were recruited from the Finnish Public Sector Study, from hospital wards that belonged to the top or bottom quartiles on job strain. Participants’ own job strain was at least as high in high-strain group or low in low-strain group as the ward’s average. The study included three-week measurements with sleep diary and actigraphy. Psychomotor Vigilance Test (PVT) was performed during one pre-selected morning and night shift and a day off. Sleep efficiency before morning shifts was lower in the high-strain than low-strain group (p=0.03). Low-strain group took more often (72 vs. 45%; p<0.01) and longer naps (62 vs. 35 min; p=0.01) before the first night shift than high-strain group. Difficulties initiating sleep were more common in high-strain group, especially after evening shifts (p<0.01). High-strain group had more often at least one lapse in PVT during the night shift (p=0.02). Average sleep duration (06:49h) and efficiency (89%) did not differ between these groups. In conclusion, high job strain is associated with difficulties initiating sleep and reduced psychomotor vigilance in night shifts. Shift working contributed to impaired sleep in both high and low job strain group. Individual and organization-based actions are needed to promote sufficient sleep in shift working nurses, especially with high job strain.
A cross-sectional study was conducted to explore the potential association between work environment and/or stress coping ability, and depressive status among caregivers working for “group homes (GHs)” in Japan. In January 2010, 438 out of 700 caregivers working at GHs in Sapporo City returned completed questionnaires to us. The questionnaires consisted of the Center of Epidemiological Scales-Depression, items about worker’s attributions, Ozeki’s coping scale, and so on. An analysis using a logistic regression model was used to find the associations adjusting for gender and age. Subjects who were 45 yr or older, had a spouse, had job training, a standard workload and scored high in emotion-oriented coping were significantly associated with a decreased risk of depression. Subjects who were less proud of their job, less willing to continue care for the frail elderly and had fewer acceptances by their supervisors or colleagues for consultation were significantly associated with an increased risk of depression. This study supports our hypothesis that there can be possible variables among individual factors, work environment and/or coping style for stress which may modulate a risk on the depressive status of caregivers.
Excessive workplace heat exposures create well-known risks of heat stroke, and it limits the workers’ capacity to sustain physical activity. There is very limited evidence available on how these effects reduce work productivity, while the quantitative relationship between heat and work productivity is an essential basis for climate change impact assessments. We measured hourly heat exposure in rice fields in West Bengal and recorded perceived health problems via interviews of 124 rice harvesters. In a sub-group (n = 48) heart rate was recorded every minute in a standard work situation. Work productivity was recorded as hourly rice bundle collection output. The hourly heat levels (WBGT = Wet Bulb Globe Temperature) were 26–32°C (at air temperatures of 30–38°C), exceeding international standards. Most workers reported exhaustion and pain during work on hot days. Heart rate recovered quickly at low heat, but more slowly at high heat, indicating cardiovascular strain. The hourly number of rice bundles collected was significantly reduced at WBGT>26°C (approximately 5% per°C of increased WBGT). We conclude that high heat exposure in agriculture caused heat strain and reduced work productivity. This reduction will be exacerbated by climate change and may undermine the local economy.
In Taiwan, relevant mid-term plans and projects of mitigating occupational hazards have been launched in recent years in the hopes of lowering the incidence of occupational hazards. In light of the lack of objective methodologies for researches on issues pertaining occupational safety and health, this research aims to explore the priorities of safety and health issues through focal groups, expert questionnaires and interviews on relevant issues such as hazard installations identified in R181 Prevention of Major Industrial Accidents Recommendation, 1993 proposed during the 18th World Congress on Safety and Health at work in Seoul 2008. Results revealed that distribute reports of major domestic/foreign occupational disasters to relevant sectors for the prevention of major accidents is needed, both from the importance and feasibility analysis. It is the only topic that scored over 4 points in average for expert and focal group consensus. Furthermore, the experts and focal groups came to consensus in the ranking of priority for 4 items, namely: 1) Installations containing/using large quantities of hazardous materials should be prioritized for inspection, 2) Incorporation of hazard installation review/inspection into OSH management system accreditation, 3) Impose operation shutdown as a means of penalty) and 4) Prioritize the promotion of preliminary PHA.
This study investigated changes in job strain in female nurses serving in a military hospital system being restructured and the effect of these changes on psychological morbidity and quality of life (QOL). Questionnaire surveys were sent twice to 618 nurses working in three military hospitals in southern Taiwan at the beginning and at follow up a half year later. A Job Content Questionnaire was used to divide subjects into high and low strain groups. The General Health Questionnaire and the WHO QOL Questionnaire were used to assess psychological morbidity and QOL. Four hundred eighteen nurses completed the study. Initially, the high strain group had a greater prevalence of psychological morbidity and lower QOL than the low strain group. At follow up, high strain group did not have a greater prevalence of psychological morbidity, though significant differences in QOL remained. Job control and social support directly affected the QOL (B=0.42, p<0.001; B=0.41, p=0.038, respectively) and the psychological demand affected directly on psychological morbidity (B=0.12, p<0.001). Job control and psychological demand are different aspects in job strain to impact the psychological morbidity and QOL in nurses working in military hospitals in Taiwan.
The identification of risk factors for depression is necessary for the primary prevention of depression. The aim of this study is to determine whether self-efficacy (SE) is associated with onset of depression among workers. Medical expenditure records of 1,803 workers, who were clerks, system engineers, researchers, and service and sales workers in a software development company, were analyzed. Gender, age, job post, marital status, working hours, and SE were measured at baseline. Participants were divided according to quartiles of SE points. Risk ratios for undergoing a medical consultation due to depression were calculated using a multivariable Cox proportional hazards model. Of the 1,803 participants, 58 underwent medical consultation due to depression during a mean of 1.8 years of follow-up. Compared with the lowest quartile (Q1) of SE, adjusted hazard ratios (HR) were 0.65 (95%CI 0.34–1.25) for Q2, 0.49 (0.24–1.00) for Q3, and 0.40 (0.18–0.88) for Q4. In men, adjusted HRs were 0.87 (0.41–1.86) for Q2, 0.61 (0.26–1.41) for Q3, and 0.37 (0.14–0.98) for Q4. In women, no significant association was found. The present study suggests that low SE is a risk factor for onset of depression among male Japanese workers.