Injuries related to shiftwork

Melatonin Relations with Energy Metabolism as Possibly Involved in Fatal Mountain Road Traffic Accidents

Previous results evidenced acute exposure to high altitude (HA) weakening the relation between daily melatonin cycle and the respiratory quotient. This review deals with the threat extreme environments pose on body time order, particularly concerning energy metabolism. Working at HA, at poles, or in space challenge our ancestral inborn body timing system. This conflict may also mark many aspects of our current lifestyle, involving shift work, rapid time zone crossing, and even prolonged office work in closed buildings. Misalignments between external and internal rhythms, in the short term, traduce into risk of mental and physical performance shortfalls, mood changes, quarrels, drug and alcohol abuse, failure to accomplish with the mission and, finally, high rates of fatal accidents. Relations of melatonin with energy metabolism being altered under a condition of hypoxia focused our attention on interactions of the indoleamine with redox state, as well as, with autonomic regulations. Individual tolerance/susceptibility to such interactions may hint at adequately dealing with body timing disorders under extreme conditions.

Satisfaction with life and the risk of occupational injury

Background

Occupational injuries increase burden on society as well as personal health. Low satisfaction with life may not only increases the risk of occupational injuries directly, but also influences other factors that increase the risk of occupational injury. Along with previous studies on the risk of occupational injury, we sought to explore the relationship between satisfaction with life and occupational injury.

Methods

The study participants were 6234workers health screened at a university hospital in Incheon. Information on occupational injury and satisfaction with life scale (SWLS) was obtained in a self-report format. Participants were allocated to one of four SWLS groups; the dissatisfied group, the slightly dissatisfied group, the slightly satisfied group, and the satisfied group. The analysis was performed using the chi-square test primarily and by logistic regression adjusted for potential confounders.

Results

In men, the un-adjusted and adjusted odds ratios (ORs) of low satisfaction with life (SWLS< 20) were 1.98(CI1.55-2.53) and 1.81(CI 1.41-2.32), respectively. When the SWLS were divided into four groups, the adjusted ORs of the slightly satisfied (20-25), slightly dissatisfied(15-19), and dissatisfied(≤14) groups were 1.21, 1.72, and 2.70, respectively. That is ORs tended to increase linearly with decreasing SWLS score (p for trend < 0.001). In women, this relation was of borderline significance at best.When subjects were dichotomized based on SWLS scores, for males, the cured and adjusted RRs of occupational injury in the low satisfaction with life group were1.91 (95% CI: 1.50-2.42) and 1.66 (95% CI: 1.30-2.13), and for females, the adjusted-RR was marginally significant (1.67; 95% CI: 0.93-2.99).When subjects were divided into four groups by SWLS scores, adjusted RRs tended to increase linearly with decreasing SWLS score for males (slightly satisfied: 1.18, 95% CI: 0.77-1.82; slightly dissatisfied: 1.65, 95% CI: 1.08-2.52; dissatisfied: 2.22, 95% CI: 1.44-3.42; p for trend < 0.001) and for females (slightly satisfied: 1.17, 95% CI: 0.42-3.30; slightly dissatisfied: 1.56, 95% CI: 0.56-4.36; dissatisfied: 2.38, 95% CI: 0.84-6.74; p for trend = 0.040).

Conclusions

This study suggests that the risk of occupational injury was higher in workers not satisfied with life, and indicates attention to satisfaction with life may promote the health of workers.

Work-Related Crushing Injuries with Amputations of Digits, Hands and Forearms

Objective

To review work-related crushing injuries leading to amputation of digits, hands and forearms, by focusing on patients' demographics, and clinical outcomes.

Design

Retrospective descriptive study.

Setting

Regional hospital, Hong Kong.

Patients

Patients with work-related crushing injuries causing amputation of digits, hands or forearms admitted to hospital for treatment from January 2003 to August 2005.

Methods

Patients' age, sex, past medical history, occupations, context of injuries including injuring objects and levels of amputation were studied. During a 9-month follow up period, patients' need for urgent operation, length of hospital stay, duration of sick leave and change of occupational status were analysed.

Results

Eighty-eight patients were studied. The age distribution ranged from 19 to 81 years, with 50% being less than 40 years of age. Most patients (93%) were healthy adult before the injury. Industries frequently involved were construction (24%), manufacturing (17%) and transportation (14%). Machineries and metallic tools were the most common injuring objects. Eighty-four percent of the amputation injuries involved the finger(s), and 13% the thumb. Most patients (91%) required urgent operation. The mean length of hospital stay was 4 days. The mean duration of sick leave was 152 days. The estimated wage loss was around HK$145,000 per accident. Only 42% of the patients could fully resume working without job restriction.

Conclusion

Traumatic amputation as a severe work-related injury is common in Hong Kong. It frequently affects the young and healthy workforce, resulting in devastating physical and psychological disabilities. The clinical, social and economical significances are enormous and far-reaching.

Non-fatal occupational falls on the same level

The purpose of this study was to describe antecedents and characteristics of same level fall injuries. Fall incidents and costs were compiled from the Bureau of Labor Statistics and other sources from 2006-2010. This study indicated that over 29% of 'fall on same level' injuries resulted in 31 or more workdays lost. The major source of injury was 'floors, walkways or ground surfaces', and the most affected body parts were the lower extremities and the trunk. With regard to gender and age, female workers had the highest risk of falls, while advancing age coincided with an increase in incidence rates. Overall, workers in the healthcare and social assistance industry, the transportation and warehousing industry, and the accommodation and food services industry had the highest risk for 'fall on same level' injuries. Furthermore, the overall compensation cost increased by 25% from 2006-2009. Along with existing evidence, these results may facilitate the design and implementation of preventative measures in the workplace and potentially reduce fall-related compensation costs.

PRACTITIONER SUMMARY

This research presents a unique and detailed analysis of non-fatal 'fall on same level' injuries in a large population of workers from various private industries in the USA. This information can be used to prioritise designing and implementing preventive measures and to provide workers with the understanding of risk factors associated with falls in the workplace.

Selectively filtering short wavelengths attenuates the disruptive effects of nocturnal light on endocrine and molecular circadian phase markers in rats

Various physiological processes exhibit a circadian rhythm synchronized to the geophysical light/dark cycle. Our study using a rat model demonstrated that exposure to light at night suppressed the expected nocturnal rise in melatonin, increased plasma corticosterone, and disrupted core clock gene expression in the hypothalamus and the adrenal gland. These effects were prevented by filtration of a 10-nm bandwidth of light between 470 and 480 nm, whereas filtration of light between 452 and 462 nm prevented the rise of corticosterone without restoring normal melatonin secretion or hypothalamic clock gene expression. This is the first demonstration of a wavelength dependency of glucocorticoid secretion and clock gene expression. Our results in an animal model suggest that filtering a narrow bandwidth of light from nocturnal lighting may efficiently attenuate overall disruption of circadian endocrine rhythms and clock gene expression in the hypothalamus and adrenal gland. Because a narrow bandwidth of light is filtered, the color distribution of the illumination source is not altered, and this may be of practical importance for potential future studies in shift workers.

Shifting schedules: the health effects of reorganizing shift work

BACKGROUND

Approximately one fifth of workers are engaged in some kind of shift work. The harmful effects of shift work on the health and work-life balance of employees are well known. A range of organizational interventions has been suggested to address these negative effects.

METHODS

This study undertook the systematic review (following Quality Of Reporting Of Meta [QUORUM] analyses guidelines) of experimental and quasi-experimental studies, from any country (in any language) that evaluated the effects on health and work-life balance of organizational-level interventions that redesign shift work schedules. Twenty-seven electronic databases (medical, social science, economic) were searched. Data extraction and quality appraisal were carried out by two independent reviewers. Narrative synthesis was performed. The review was conducted between October 2005 and November 2006.

RESULTS

Twenty-six studies were found relating to a variety of organizational interventions. No one type of intervention was found to be consistently harmful to workers. However, three types were found to have beneficial effects on health and work-life balance: (1) switching from slow to fast rotation, (2) changing from backward to forward rotation, and (3) self-scheduling of shifts. Improvements were usually at little or no direct organizational cost. However, there were concerns about the generalizability of the evidence, and no studies reported on impacts on health inequalities.

CONCLUSIONS

This review reinforces the findings of epidemiologic and laboratory-based research by suggesting that certain organizational-level interventions can improve the health of shift workers, their work-life balance, or both. This evidence could be useful when designing interventions to improve the experience of shift work.

Visual problems among electronic and jewelry workers in Thailand

In the processes of electronic and jewelry manufacturing, workers are employed to use their skill in tiny visual tasks (1-3 mm) and near visual distances (<35 cm) that cause visual strain. This study consisted of 3 phases: 1) a survey of workers visual health status and factors affecting their visual strain; 2) the development and implementation of guidelines in the selected factories; and 3) a resurvey to document the change. The baseline survey was conducted in Samutprakan Province during October to December, 2003. Ninety-five percent of the sampled workers were female with an average age of 26.2 yr. Fifty-two percent of the workers had at least one kind of vision problem that might have affected their work performance, and 48.3% of the work sites had substandard illumination levels. The intervention included improvement of lighting conditions, the introduction of short breaks, and correction of visual performance problems. After the intervention, the inadequate lighting problem went down to 24.5%. All factories took a rest break and 20.5% of the workers with inadequate visual performance had corrected their vision in the intervention period. Comparing pre-intervention status with the end of the program, the Critical Fusion Frequency (CFF) at one hour and two hours of work were improved with statistical significance among the electronic but not the jewelry workers. In conclusion, visual problems among vision intensive industrial workers are common. Intervention programs partially but significantly improved the situation.

Effects of color temperature of illumination on physiological functions

This article presents our recent studies on the effects of color temperature on the taste sense and the influence of color temperature on bright light exposure during night rest period. Ten male Japanese and ten male Chinese were exposed to four illumination conditions (200, 1500 lx x 3000, 7500 K). Their taste threshold of four common tastes and amount of saliva were measured. It was found in both Japanese and Chinese subjects that sensitivities to sweet and bitter taste were decreased under the lower illuminance condition. Under the lower color temperature condition, sensitivity to bitter taste in Japanese and sweet taste in Chinese were decreased. Secretion of saliva increased under the lower illuminance condition in both Japanese and Chinese. Only in Chinese subjects, secretion of saliva increased under the lower color temperature condition. In a separate experiment, six male Japanese students were subjected to bright light exposure during a night rest period. They performed a mental task from 23:00 h till 02:00 h, and took a rest from 00:00 h to 01:00 h. During the rest period they were exposed to bright light (3000 lx) of three different color temperatures: 3000 K, 5000 K, and 7000 K. After exposure to bright light of 3000 K but not at other color temperatures, the EEG alpha1 band ratio and the beta band ratio at 02:00 h were higher and lower, respectively, than that at 01:00 h. These findings indicated that lower color temperature bright light exposure during a night rest break led to a reduction of subjects' arousal level during the subsequent work. Herein, we discuss these results from the viewpoint of physiological anthropology.

Prevention of injuries at work: the role of the occupational physician

OBJECTIVES

To highlight the role of occupational physician (OP) in occupational injuries (OI) prevention and management. To suggest an approach beyond traditional focus on descriptive epidemiology, engineering interventions, administrative aspects of OI prevention. To promote a person- and enterprise-tailored approach, entailing greater attention to human factors and to practical problems of the specific workplace, with a call to a leading role played by OP.

METHODS AND RESULTS

Analysis of the literature on the broader topic of OI prevention revealed thousands of publications; however, only a handful of them mention or describe the participation of OP in OI prevention. While recognizing that literature search is not the proper and only way to appreciate the current role of OP in this field, therefore, it seems necessary to call OP to a stronger effort in prevention and management of OI, through the context of a comprehensive intervention in cooperation with managers, supervisors, safety personnel and workers, focusing on specific needs of each enterprise. The following areas of OP intervention were examined: risk assessment, health surveillance, management, scientific research and health education. Within each of these topics, possible contributions, methodologies, instruments available for the OP were discussed, taking into account the relevant literature. Pathways for practical applications were illustrated, e.g., OI data generation and analyses, predictors of OI, fitness for work, case management, team work, educational issues, first aid, suggestion for OP contribution in specific research questions.

CONCLUSIONS

OI continue to take a remarkable toll from individuals and society. New multidisciplinary interventions are needed to prevent OI. Focused activities at the single worksite with a central role from OP are definite options. OP is an effective interface between workforce and management and may offer, through a proactive approach, valuable practical and cultural contributions, while respecting technical and ethical guidelines of occupational health professionals.

Subjective and Objective Evaluation of Sleep and Performance in Daytime Versus Nighttime Sleep in Extended-Hours Shift-Workers at an Underground Mine

Extended hours of shift work has the potential for adverse consequences for workers, particularly during the nightshift, such as poorer sleep quality during the day, increased worker fatigue, and fatigue-related accidents and decreased work performance. This study examined subjective and objective measurements of sleep and performance in a group of underground miners before and after the change from a backward-rotating 8-hour to a forward-rotating 10-hour shift schedule. The purpose of this study was to evaluate the short- and long-term impact of a shift schedule change on sleep and performance. The results demonstrated improved subjective and objective measures of sleep and performance on the new 10-hour nightshift schedule. The 10-hour nightshift workers subjectively reported more refreshing sleep, fewer performance impairments and driving difficulties than 8-hour nightshift workers. The results of the objective measures of sleep and performance on the 10-hour nightshifts were overall similar or possibly better than those measured on the 10-hour dayshifts. These are some of the first data to suggest that a nightshift that does not encompass the entire night period could have significant benefits to shift-workers. We suggest that these benefits are mostly the result of the timing of the new nightshift start and end times rather than other shift-schedule factors.

Fatigue as a risk factor for being injured in an occupational accident: results from the Maastricht Cohort Study

AIMS

To determine whether fatigue and need for recovery are risk factors for being injured in an occupational accident.

METHODS

These associations were investigated within the Maastricht Cohort Study of "Fatigue at Work", a prospective cohort study of employees from a wide range of companies and organisations. For 7051 employees information was available on fatigue as measured with the Checklist Individual Strength (CIS), need for recovery as measured with the VBBA, and possible confounding factors such as age, smoking, alcohol consumption, educational level, shift work, and work environment. Information on the risk factors was collected in May 1999 and January 2000, before the occurrence of the occupational accidents. The incidence of being injured in an occupational accident was inventoried over the year 2000. A total of 108 employees reported having been injured in an occupational accident in 2000.

RESULTS

For the highest CIS fatigue score tertile a for age, gender, educational level, smoking, shift work, and work environment, adjusted relative risk for being injured in an occupational accident of 1.29 (95% CI: 1.03 to 2.78) was found compared to the lowest tertile, and for the highest tertile of need for recovery a relative risk of 2.28 (95% CI: 1.41 to 3.66) was found.

CONCLUSIONS

Fatigue and need for recovery were found to be independent risk factors for being injured in an occupational accident. This means that in the push back of occupational accidents, fatigue, and even more importantly need for recovery, need special attention.

Efficacy of bright light and sleep/darkness scheduling in alleviating circadian maladaptation to night work

We tested the hypothesis that circadian adaptation to night work is best achieved by combining bright light during the night shift and scheduled sleep in darkness. Fifty-four subjects participated in a shift work simulation of 4 day and 3 night shifts followed by a 38-h constant routine (CR). Subjects received 2,500 lux (Bright Light) or 150 lux (Room Light) during night shifts and were scheduled to sleep (at home in darkened bedrooms) from 0800 to 1600 (Fixed Sleep) or ad libitum (Free Sleep). Dim light melatonin onset (DLMO) was measured before and after the night shifts. Both Fixed Sleep and Bright Light conditions significantly phase delayed DLMO. Treatments combined additively, with light leading to larger phase shifts. Free Sleep subjects who spontaneously adopted consistent sleep schedules adapted better than those who did not. Neither properly timed bright light nor fixed sleep schedules were consistently sufficient to shift the melatonin rhythm completely into the sleep episode. Scheduling of sleep/darkness should play a major role in prescriptions for overcoming shift work-related phase misalignment.

Information retrieval in systematic reviews: challenges in the public health arena

BACKGROUND

Information retrieval for systematic reviews in occupational injuries and other public health areas is much more elusive than retrieval for reviews in clinical medicine, due to the interdisciplinary nature of the field and the lack of a significant body of evaluative literature.

OBJECTIVE

The objective of this study is to provide information about challenges and methodology in relevant literature retrieval for systematic reviews in the effectiveness of strategies to prevent occupational injury.

METHODS

Participants from Injury Control Research Centers and Agricultural Health and Safety Centers identified 12 areas of occupational injury and evaluated the effectiveness of interventions in each area. A systematic review of the literature was conducted, and results were critically reviewed and summarized.

RESULTS

The search strategy captured 41,871 abstracts or titles across all research topics. After screening, 1356 documents were identified as being potentially eligible studies. Relevant articles were also identified through gleaning references and contact with professionals in the field.

CONCLUSIONS

Literature reviews in the field of occupational injury cannot be limited to database searches. Much of the literature is not well-indexed, and librarians must employ information retrieval methods other than database searching to retrieve relevant literature in the field.