Occupational health hazards resulting from elevated work rate situations.

Some occupational health hazards resulting from an elevated rate of work due to recent mechanization and automatization are discussed on the basis of results of health examinations. A rapid increase of a cervicobrachial disorder among young cash register and packing machine operators has been observed. Switching to the use of electronic cash registers has been shown to have only limited efficacy due to increased operation speed, and high-speed complex finger and hand movements of packer operators have also proven to be as hazardous as key-board operations. The high incidence of low-back pain, in particular gradually developing pain, among workers in electric power supply work has been suggested to be the result of quick and intensified work to meet increasing supply demand. Likewise, the workload of electric locomotive and bullet train drivers has increased in accordance with increased train speeds, and has been shown to have had significant effects on their health particularly in regards to neural strain, intra-cab environment such as air pressure change, vibration, and noise, and rotation on irregular shifts. New steps seem required therefore to meet the new health problems arising from a combination of modern technological changes and elevated working speeds.     

Asymmetry of the a-b ridge count in low-back pain sufferers

Fluctuating asymmetry of paired morphological structures is regarded as a measure of developmental stability. To test whether poorly canalized individuals are highly sensitive to postnatal environmental influence, we accepted the exogenous disease low-back pain as an example of such sensitivity. Asymmetry of the palmar a-b ridge count was examined in 217 males suffering from low-back pain against 300 healthy controls. Low-back pain patients showed significantly higher values of asymmetry indices indicating lower developmental stability. The results suggest that dermatoglyphic asymmetry can mark phenotypes weakly adapted to postnatal stress.     

Assessment of work-related muscle strain by using surface EMG during test contractions interposed between work periods of simulateted mushroom picking

Surface electromyograms(EMG) during test contractions (TCs) were studied to assess the muscle strain in simulated mushroom picking. Additionally, the duration of the TC for the effective assessment was investigated. Nine female subjects performed standardized shoulder abduction and a stooped posture for one minute as TCs. Each experiment consisted of a 60-min rest, three work periods (W1-W3), a 30-min rest, and two work periods (W4 and W5) separated by a 30-min rest period. The duration of each work period was about 20 min. A total of 18 TCs was performed between the work periods and every 10 minutes in the rest periods. EMGs were recorded from the trapezius, infraspinatus, deltoid, and erector spinae muscles. The amplitude of EMG (AEMG) and mean power frequency (MPF) of EMG were calculated. Each TC was divided equally into three parts. Ratings of perceived exertion (RPE) in the neck, shoulder and low-back were reported during TCs. The work increased RPE of all the parts. AEMG and RPE were increased and MPF was decreased by W1, W2 and W3 in the neck and shoulder muscles. MPF of the erector spinae was increased by the work. The results were not affected by the duration of TCs and the parts during the TCs. AEMG and MPF fluctuated before W1 although the changes of RPE were small. Averaging several TCs was recommended to get stable results from TCs. EMG changes and appropriate TC conditions were discussed in relation to the adaptation in fatiguing contractions.     

The ergonomic evaluation of work-related musculoskeletal disorders among construction labourers working in unorganized sectors in West Bengal, India

The present study aimed at ergonomic evaluation of the prevalence of work-related musculoskeletal disorders among construction labourers working in unorganized sectors in West Bengal, India. A modified Nordic questionnaire was applied to one hundred forty male and ninety female construction labourers to acquire information about musculoskeletal symptoms like pain in different body parts. Work-rest schedules of the labourers in different work activities were studied. Working postures were analyzed by means of the Rapid Entire Body Assessment (REBA) tool. Body part discomfort (BPD) scale was used to assess the intensity of feeling of discomforts in the different body parts. It was revealed that the labourers performed repetitive, stressful work for a long period of time in a single work-rest cycle and the load lifted and carried by them were more than the NIOSH recommended weight limit. The analyses of working postures revealed that most of their working postures were unsafe and ranked under REBA action level 3 and 4. The results obtained by applying the Nordic questionnaire and BPD scale revealed that the prevalence of pain in various regions of the body, especially low-back pain, was alarmingly high in both male and female labourers. Training for safe lifting of materials, proper work-rest schedule, modifications of some working procedures and the use of ergonomically designed equipment may certainly reduce the work-related musculoskeletal disorders and improve the health status of construction labourers working in unorganized sectors.     

Adaptation to night shifts and synchronisation processes of night workers

Human beings are accustomed to being active and awake during the day, and asleep and rest at night. Since we live in a society which is organised predominantly along daytime activity, therefore working in the night shift may deeply disrupt our social and family life. It is also a well-known fact that night shift causes fatigue and circadian disruption. The basic manifestation of fatigue and circadian rhythm has been linked to health and safety problems, involving decrements in psychophysical and physiological functions, plus subjective complaints. In this context quantitative relationships between shift work and circadian rhythm need to be assessed to explore suitable time schedule, and to minimise sleep depth and fatigue. There is also a great need to discuss circadian disruption, sleepiness and the increasing cost of work related illness among night workers. In this regard, some aspects of fatigue and circadian disruption caused from night shift work are revealed in this paper aiming to increase workers' health, safety and well being as well as productivity. Light/dark cycle and social stimuli issues acting on the circadian timing systems are also explored to solicit opinions and discussion on the controversy of night work. Suggestions are therefore likewise given to enhance workers' adaptation to night shift and synchronization process.     

Low-back loading in lifting two loads beside the body compared to lifting one load in front of the body

Low-back load during manual lifting is considered an important risk factor for the occurrence of low-back pain. Splitting a load, so it can be lifted beside the body (one load in each hand), instead of in front of the body, can be expected to reduce low-back load. Twelve healthy young men lifted 10 and 20-kg wide and narrow loads in front of the body (the single-load lifts). These single-load lifts were compared to a lifting condition in which two 10-kg loads (a total of 20 kg) were lifted beside the body (the split-load lift). Lifts were performed from an initial hand height of 29 cm with four different lifting techniques (stoop, squat, straddle and kneeling techniques). Using measured kinematics, ground reaction forces, and electromyography, low-back loading (3D net moments and spinal forces at the L5/S1 joint) was estimated. Lifting a 20-kg split-load instead of a 20-kg single-load resulted in most cases in a reduction (8–32%) of peak L5/S1 compression forces. The magnitude of the reduction was roughly comparable to halving the load mass and depended on lifting technique and load width. The effects of load-splitting could largely be explained by changes in horizontal distance between the load and L5/S1.     

Effectiveness of massage therapy for subacute low-back pain: a randomized controlled trial

BACKGROUND: The effectiveness of massage therapy for low-back pain has not been documented. This randomized controlled trial compared comprehensive massage therapy (soft-tissue manipulation, remedial exercise and posture education), 2 components of massage therapy and placebo in the treatment of subacute (between 1 week and 8 months) low-back pain. METHODS: Subjects with subacute low-back pain were randomly assigned to 1 of 4 groups: comprehensive massage therapy (n = 25), soft-tissue manipulation only (n = 25), remedial exercise with posture education only (n = 22) or a placebo of sham laser therapy (n = 26). Each subject received 6 treatments within approximately 1 month. Outcome measures obtained at baseline, after treatment and at 1-month follow-up consisted of the Roland Disability Questionnaire (RDQ), the McGill Pain Questionnaire (PPI and PRI), the State Anxiety Index and the Modified Schober test (lumbar range of motion). RESULTS: Of the 107 subjects who passed screening, 98 (92%) completed post-treatment tests and 91 (85%) completed follow-up tests. Statistically significant differences were noted after treatment and at follow-up. The comprehensive massage therapy group had improved function (mean RDQ score 1.54 v. 2.86-6.5, p < 0.001), less intense pain (mean PPI score 0.42 v. 1.18-1.75, p < 0.001) and a decrease in the quality of pain (mean PRI score 2.29 v. 4.55-7.71, p = 0.006) compared with the other 3 groups. Clinical significance was evident for the comprehensive massage therapy group and the soft-tissue manipulation group on the measure of function. At 1-month follow-up 63% of subjects in the comprehensive massage therapy group reported no pain as compared with 27% of the soft-tissue manipulation group, 14% of the remedial exercise group and 0% of the sham laser therapy group. INTERPRETATION: Patients with subacute low-back pain were shown to benefit from massage therapy, as regulated by the College of Massage Therapists of Ontario and delivered by experienced massage therapists.     

The prognosis of acute and persistent low-back pain: a meta-analysis

Background:

Although low-back pain is a highly prevalent condition, its clinical course remains uncertain. Our main objective was to systematically review the literature on the clinical course of pain and disability in patients with acute and persistent low-back pain. Our secondary objective was to investigate whether pain and disability have similar courses.

Methods:

We performed a meta-analysis of inception cohort studies. We identified eligible studies by searching MEDLINE, Embase and CINAHL. We included prospective studies that enrolled an episode-inception cohort of patients with acute or persistent low-back pain and that measured pain, disability or recovery. Two independent reviewers extracted data and assessed methodologic quality. We used mixed models to determine pooled estimates of pain and disability over time.

Results:

Data from 33 discrete cohorts (11 166 participants) were included in the review. The variance-weighted mean pain score (out of a maximum score of 100) was 52 (95% CI 48–57) at baseline, 23 (95% CI 21–25) at 6 weeks, 12 (95% CI 9–15) at 26 weeks and 6 (95% CI 3–10) at 52 weeks after the onset of pain for cohorts with acute pain. Among cohorts with persistent pain, the variance-weighted mean pain score (out of 100) was 51 (95% CI 44–59) at baseline, 33 (95% CI 29–38) at 6 weeks, 26 (95% CI 20–33) at 26 weeks and 23 (95% CI 16–30) at 52 weeks after the onset of pain. The course of disability outcomes was similar to the time course of pain outcomes in the acute pain cohorts, but the pain outcomes were slightly worse than disability outcomes in the persistent pain cohorts.

Interpretation:

Patients who presented with acute or persistent low-back pain improved markedly in the first six weeks. After that time improvement slowed. Low to moderate levels of pain and disability were still present at one year, especially in the cohorts with persistent pain.Low-back pain is a highly prevalent condition associated with work absenteeism, disability and large health care costs; however, there is still disagreement about prognosis. For example, the European guidelines for the management of low-back pain states that 90% of patients with acute low-back pain recover in six weeks.¹ In contrast, some well-conducted cohort studies show a less optimistic picture, providing short-term estimates of recovery ranging from 39% to 76%.^2,3 This wide range of estimates of prognosis is likely explained by differences in cohorts and definitions used to define the onset or conclusion of an episode of low-back pain. Because very different definitions of recovery are often used, it is difficult to obtain pooled estimates of recovery rates. Instead, it might be more useful to describe the clinical course of low-back pain in terms of expected changes in pain or disability over time.A recent systematic review⁴ summarized the prognostic factors for persistent disabling low-back pain but did not describe the clinical course. The only meta-analysis to investigate the clinical course of acute low-back pain was published in 2003.⁵ This review concluded that both pain and disability improve rapidly within weeks (mean reduction of 58% of initial scores in the first month) and recurrences are common. A limitation of this review was that, although it retrieved 15 studies, only 5 were cohort studies; the remaining 10 were randomized controlled trials. Randomized trials often have narrow inclusion criteria and low rates of participation, which make them less suitable for inferring prognosis. The best design to describe the prognosis of a condition is a cohort study enrolling a representative sample of incident cases (i.e., by including patients at a similar early point in their condition).^6,7 Such studies are known as inception cohort studies. To the best of our knowledge, no review has yet investigated the clinical course of pain and disability among people with persistent low-back pain (subacute and chronic). Thus, the prognosis for people with persistent low-back pain is still uncertain.The aim of our study was to systematically review the clinical course of pain and disability in patients with acute and persistent low-back pain. We included only inception cohort studies. Our second aim was to investigate whether pain and disability have similar courses.     

Measurement of, and some reasons for, differences in eating habits between night and day workers

A questionnaire was designed to assess the following: why working people chose to eat or not to eat at a particular time of day; the factors that influenced the type of food eaten; and subjective responses to the meal (hunger before, enjoyment during, satiety afterward). Self-assessments were done every 3 h during a typical week containing work and rest days, by one group of 50 day workers and another group of 43 night workers. During the night work hours compared to rest days, night workers evidenced a significantly altered food intake, with a greater frequency of cold rather than hot food (p < 0.001). The type and frequency of meals were influenced significantly more (p < 0.05) by habit and time availability and less by appetite. This pattern continued into the hours immediately after the night shift had ended. In day workers food intake during work hours, compared to rest days, was also influenced significantly more often (p < 0.05) by time availability than hunger, but less so than with night workers. Moreover, day workers were less dependent than night workers upon snacks (p = 0.01), and any significant differences from rest days did not continue beyond work hours. Not only did night workers change their eating habits during work days more than did day workers but also they looked forward to their meals significantly less (p < 0.001) and felt more bloated after consuming them (p < 0.05), such effects being present to some extent during their rest days also. These findings have clear implications for measures designed to ease eating problems that are commonly problematic in night workers.     

The influence of visual display terminal use on the physical and mental conditions of administrative staff in Japan

Visual display terminals (VDT) are standard equipment for many office workers. Their use, however, may increase the risk of developing adverse conditions related to vision, the musculoskeletal system, and mental health. We carried out a survey among 3070 workers aged 18 to 67 years (mean, 39.9 years) at a prefectural administrative office, in which 76% of subjects were visual display terminal (VDT) users. We examined the relationship between duration of daily VDT use and eyestrain, neck or upper extremity pain, back pain, and mental health, and estimated the effect of breaks and rest during VDT work on these symptoms. The 12-item General Health Questionnaire (GHQ-12: total scores ranged from 0 to 12) was used to identify potential poor mental health status, and subjects with 4 or more were considered to have symptoms of psychological distress. Seventeen percent of subjects reported eyestrain, 19.1% reported upper extremity pain, 11.6% reported back pain, and 17% of subjects had GHQ-12 scores of 4 or higher. Logistic regression analysis showed that duration of daily VDT use and lack of breaks and rest during VDT work were significantly associated with eyestrain, neck or upper extremity pain, back pain, and psychological distress. In order to protect users from the adverse effects associated with VDT work, reducing daily VDT exposure, taking breaks, and rest during VDT work are important.     

Measurement of,and Some Reasons for,Differences in Eating Habits Between Night and Day Workers

A questionnaire was designed to assess the following: why working people chose to eat or not to eat at a particular time of day; the factors that influenced the type of food eaten; and subjective responses to the meal (hunger before, enjoyment during, satiety afterward). Self-assessments were done every 3h during a typical week containing work and rest days, by one group of 50 day workers and another group of 43 night workers. During the night work hours compared to rest days, night workers evidenced a significantly altered food intake, with a greater frequency of cold rather than hot food (p < 0.001). The type and frequency of meals were influenced significantly more (p < 0.05) by habit and time availability and less by appetite. This pattern continued into the hours immediately after the night shift had ended. In day workers food intake during work hours, compared to rest days, was also influenced significantly more often (p < 0.05) by time availability than hunger, but less so than with night workers. Moreover, day workers were less dependent than night workers upon snacks (p = 0.01), and any significant differences from rest days did not continue beyond work hours. Not only did night workers change their eating habits during work days more than did day workers but also they looked forward to their meals significantly less (p < 0.001) and felt more bloated after consuming them (p < 0.05), such effects being present to some extent during their rest days also. These findings have clear implications for measures designed to ease eating problems that are commonly problematic in night workers.     

Working hours and fatigue of Japanese flight attendants (FA).

There have been some reports concerning high complaint rates of fatigue or fatigue-related symptoms including lower back pain in flight attendants (FA). Thus, the relations of working conditions with work stress and fatigue symptoms were studied chiefly by focusing on working hours. From analysis of the time-table and fatigue symptoms of workers on international flights, it was suspected that there were some work-related factors jointly causing serious FA fatigue symptoms; night time and early morning work, long flight hours and a large time difference, thus disturbing their biological rhythms. On domestic flights, showing up early in the morning and debriefing late in the night were often observed together with a highly irregular FA time schedule. By statistical analyses, some factors including long working hours, frequent landing and late debriefing hours were considered to contribute significantly to the high fatigue complaint rates. Thus, it should be emphasized that many countermeasures are necessary to improve FA working conditions including working hours, rest on the airplane (ONO et al., 1990) and sleep during layover, in order to reduce their work stress and fatigue symptoms.     

Effects of industrialization on working schedules.

Recent increase in industrialization has resulted in attention being drawn to diversity of working schedules and their interrelation with content of work. The results of joint research revealed that adaptation to industrial jobs is made difficult because of urban conditions and modern work-control systems, such as workers in flexible-working-time systems who apparently favored regular daily working cycles. Long overtime work in smaller undertakings and the spread of shift systems are two important features of industrial work schedules, each being dominant among skilled and non-skilled jobs. Another important facet is the problem of intra-shift work-rest schedules significant for machine operations and vigilance tasks. It is suggested that phases of work that become intolerable are correlated with unnatural work rhythms. More emphasis should thus be laid on both phase-shifted work and non-self-governing work, the key factor being the relevance of attained data to real work in the whole course of schedules of work and rest.     

Mild manifestations of COVID-19 in healthcare workers

Medical staff treating Coronavirus Disease 2019 (COVID-19) patients are at high risk for exposure to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and many have been infected, which may cause panic among medical workers, their relatives, health professionals, and government leaders. We report the epidemiologic and clinical characteristics of healthcare workers and that the majority of infected medical staff had milder symptoms/conditions with a better prognosis than admitted patients. Timely improvement to medical staff’s working conditions such as allowing adequate rest and providing sufficient medical protection is extremely important.     

Differential effects of mental concentration and acute psychosocial stress on cervical muscle activity and posture

Physical and psychosocial stressors in the workplace have been independently associated with the development of neck pain, yet interactions among these risk factors remain unclear. The purpose of this study was to compare the effects of mentally challenging computer work performed with and without exposure to a psychosocial stressor on cervical muscle activity and posture. Changes in cervical posture and electromyography of upper trapezius, cervical extensor, and sternocleidomastoid muscles were compared between a resting seated posture at baseline, a low stress condition with mental concentration, and a high stress condition with mental concentration and psychosocial stress in sixty healthy office workers. Forward head posture significantly increased with mental concentration compared to baseline, but did not change with further introduction of the stressor. Muscle activity significantly increased from the low stress to high stress condition for both the dominant and non-dominant upper trapezius, with no corresponding change in activity of the cervical extensors or flexors between stress conditions. These findings suggest that upper trapezius muscles are selectively activated by psychosocial stress independent of changes in concentration or posture, which may have implications for the prevention of stress-related trapezius myalgia in the workplace.     

The Short-Doyle Act; California community mental health services program: background and status after one year

The Short-Doyle Act seeks to encourage the treatment of a patient suffering from a psychiatric disorder in his home community, with the assistance of local medical resources. One corollary of this program is the closer working together of the psychiatrist and the rest of the medical profession.A second goal of the act is the application of the public health principles to mental illnesses and mental retardation. Educational and consultative services provide implementation of these principles.     

THE SHORT-DOYLE ACT—California Community Mental Health Services Program: Background and Status After One Year

The Short-Doyle Act seeks to encourage the treatment of a patient suffering from a psychiatric disorder in his home community, with the assistance of local medical resources. One corollary of this program is the closer working together of the psychiatrist and the rest of the medical profession.A second goal of the act is the application of the public health principles to mental illnesses and mental retardation. Educational and consultative services provide implementation of these principles.     

Occupational diseases, working ability and employment status in the working population of Croatia

The paper gives insight into the working ability and employment status of workers with recognized occupational diseases in Croatia. The analysis based on working ability data from 212 workers shows that 12 (5.5%) workers have general disability for work, 75 (35.5%) occupational disability for work, 98 (46.4%) danger of disability onset, 13 (6%) no disability and 14 (6.5%) are sent for further medical treatment. The highest frequency of occupational diseases is in the group of workers with 41-50 years of age, in the category of 20-24 exposure years. Official data imply that the incidence rate of occupational diseases in Croatia is 4 times lower than in European Union. Such a low incidence rate derives from problems in the system of healthcare and health insurance, and also from problems in the system of monitoring and registering of occupational diseases.     

Variations in blood supply allocations for quadrupedal and for bipedal posture and locomotion

Hemodynamics and orthodynamics were investigated in quadrupeds (dogs) and in bipeds (humans). The subjects were investigated at rest in supine or lateral posture, in quadrupedal and then in bipedal posture, and during locomotion. Quadrupedalism in humans was with subjects on their hands and knees. Bipedalism in dogs was on hindlimbs with the forelimbs held by a technician. Blood flow in the main arteries of the body (aorta, external and internal carotid, subclavian, and femoral) was measured by sonography. Positional variations between the main bones of the body were determined from X-rays. This study investigated the reallocation of blood supply to different regions of the body when it switches from quadrupedal to bipedal posture and locomotion. Compared with resting posture, the principal findings are 1) cardiac output shows a minimal increase for humans in bipedal stance and a noticeable increase for dogs as well as humans in quadrupedal stance; 2) quadrupedal stance in humans and dogs and bipedal stance in dogs require increased blood supply to the muscles of the neck, back, and limbs, while human bipedal stance requires none of these; 3) cerebral blood flow (internal carotid) in humans did not change as a result of bipedal posture or locomotion, but showed a noticeable drop in quadrupedal posture and an even further drop in quadrupedal locomotion. The conclusion is that erect posture and encephalization produced a noticeable readjustment and reallocation of blood flow among the different regions of the body: This consisted in shifting a large volume of blood supply from the musculature to the human brain.     

The change of working posture in Manggur decreases cardiovascular load and musculoskeletal complaints among Balinese gamelan craftsmen

Manggur, which means to plane down or sharpen, is a manual process in producing copper blades of Balinese gamelan orchestra. The craftsmen of Manggur work 6 to 8 hours a day, sitting on the floor with folded legs and hunched back. Because the craftsmen often complain about musculoskeletal problems after having completed a full day work, an ergonomic intervention was made by changing their usual working posture (the first working posture) into working on tables while sitting on chairs for one hour and alternately standing for half an hour (the second working posture). Treatment by subject design was applied to 22 randomly chosen craftsmen. Resting heart rate and working heart rate were measured by using a stopwatch, and the number of musculoskeletal complaints were recorded with Nordic Body Map Questionnaire. As a result, the second working posture caused significant reductions in working heart rate, work pulse (the difference between working heart rate and resting heart rate) and the number of musculoskeletal complaints. These results suggest that the change of working posture in manggur decreases cardiovascular load and musculoskeletal strain among Balinese gamelan craftsmen.