A cross-sectional study of the upper limb non-neurogenic physical findings in computer operators and their relation to pain and neurological findings.

OBJECTIVES: The character of upper limb disorders in computer operators is subject to debate. While nerve involvement is suggested by the presence of pain, paresthesia and subjective weakness, these symptoms are mainly interpreted as related to pathologies outside the nervous system. Findings in a previous study involving computer operators indicated peripheral nerve afflictions with specific locations in symptomatic subjects. Based on the same sample, this study addresses the relation of non-neurogenic findings to pain and neurological findings. MATERIAL AND METHODS: Overall, 96 computer operators scored their perceived pain in the neck, shoulder, elbow, and wrist/hand on a Visual Analogue Scale of 0-9. They underwent 2 sets of blinded physical examinations of selected non-neurogenic and neurological items, respectively. The authors analyzed correlations between the scores of each non-neuropathic finding, and a) mean pain scores for each and all regions, and b) scores for neurological patterns reflecting brachial plexopathy, median neuropathy (the elbow), and posterior interosseous neuropathy, respectively, and their combination. Kendall's rank correlation test was applied for all statistical analyses. RESULTS: A median pain level of 1 or 0.5 was reported by 80 and 57 participants on the mouse-operating or contralateral side, respectively. Non-neurogenic and neurological findings were frequent. The mean overall pain correlated with palpation soreness of the neck insertions, and of the trapezius and supraspinatus muscles. Neck and elbow pain correlated with palpation soreness at the neck insertions and the lateral epicondyles, respectively. Significant correlations on the mouse-operating side were identified between posterior interosseous neuropathy and lateral epicondyle soreness, and between median neuropathy and any neurological pattern, and trapezius and lateral epicondyle soreness. CONCLUSIONS: Pain correlated with palpation soreness, which again correlated with the neurological patterns. Palpation soreness may be less significant as a marker of a painful disorder as it correlated no better with regional than with overall pain. The physical examination of computer operators should include a sufficient neurological assessment. Int J Occup Med Environ Health. 2021;34(5):679-91.

Studies of upper limb pain in occupational medicine, in general practice, and among computer operators
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Diagnostic consensus criteria cannot be applied in a major proportion of patients with upper limb complaints, many of which are regarded as "non-specific". The three empirical studies in this thesis aimed to address this diagnostic challenge by incorporating representative neurological qualities in the physical examination.
Patterns of muscle weakness, sensory abnormalities and nerve trunk allodynia based on the nerves' topography and their motor and cutaneous innervation were defined to reflect peripheral nerve afflictions and their locations. The physical examination was first validated on patients in clinical occupational medicine. Next, the neurological patterns were studied among computer operators in order to contribute to the characterization of their disorder. Finally, self-reported work-exposures for patients in general practice presenting with symptoms and findings consistent with brachial plexopathy were compared with the exposures of matched control patients without upper limb symptoms.
The inter-rater reliability of manual individual muscle testing, and of assessments of sensibility (touch, pinprick and vibration) and mechanosensitivity of nerve trunks was generally moderate to good. Patterns of findings in accordance with neuropathy at ten locations were identified with moderate to good reliability. The identified patterns reflected the presence of symptoms with high positive and negative predictive values. An examination limited to the assessment of strength in six muscles was shown to be sensitive but non-specific.
Computer operators with severe upper limb complaints are characterized by rather uniform physical findings in accordance with an infraclavicular brachial plexopathy in combination with median and posterior interosseous neuropathy at elbow level. In spite of reduced symptoms at follow-up, the prognosis in terms of work-status and persisting pain is serious. A cross-sectional study of computer operators in current work showed that individual and patterns of neurological findings in symptomatic subjects reflected these three locations of focal neuropathy. Pain was common in the studied sample, but of low intensity. Physical abnormalities were frequent and related to summarized pain. Patterns in accordance with brachial plexopathy, and median (elbow) and posterior interosseous neuropathies were identified in a minor proportion of limbs, in particular in the mouse-operating limb. A stretching course designed to improve the mobility and available space for the nerves at the three locations reduced the pain level but did not influence physical findings at follow-up. The relation of symptoms to the identified neurological patterns and the effect of stretching provide additional support to the construct validity of the applied neurological examination. This study indicates the role of nerve afflictions in computer-related upper limb disorders.
The most frequent pattern in the first two studies was in accordance with brachial plexopathy. Therefore additional analyses addressed the relation of this condition to me-chanical exposures at work. Whether assessed as the extent during the workday or days per week, many exposures, in particular adverse upper limb postures, repetitive work, work pace, and the use of force, were significant risk indicators for brachial plexopathy with clear dose-response relationships.
The identification of patterns of physical findings that reflect the function of the peripheral nerves appears to be a rewarding diagnostic procedure in subjects with upper limb symptoms. The relation of patterns to symptoms indicates the diagnostic feasibility of the examination and can contribute to explain symptoms in workers such as computer operators. Patterns in accordance with brachial plexopathy are frequent and related to mechanical work-exposures.

Hypertension among Danish seafarers.

BACKGROUND: Due to the high prevalence of arterial hypertension and its role in the development of atherosclerosis, myocardial infarction and stroke, hypertension is a major public health challenge worldwide. There is limited knowledge of the prevalence of hypertension among seafarers who, however, are known to have an excess morbidity and mortality from these disorders. This article addresses the prevalence of hypertension among Danish seafarers and discusses potential risk factors for hypertension in maritime settings. MATERIALS AND METHODS: A representative sample of 629 Danish seafarers who had statutory medical examinations was studied from the beginning of October 2011 to the end of June 2012. The medical examination included measurements of blood pressure. The prevalence of hypertension in the study population was stratified by age, work place on board, smoking status, alcohol intake, and body mass index. RESULTS: The overall prevalence of hypertension in the study population was 44.7% (95% CI 40.8-48.6). In a comparison sample of adult Danes, the crude rate of hypertension was 12.6%. In addition, 41.8% (95% CI 38.0-45.7) of seafarers were pre-hypertensive. Hypertension was particularly increased among younger seafarers. The proportion of seafarers in antihypertensive treatment was low, in particular among the young seafarers. CONCLUSIONS: Hypertension is a major health issue among Danish seafarers. In addition to ensuring antihypertensive treatment when needed, individual and collective prevention should address lifestyle issues as well as physical and psychosocial exposures at sea.

Prevalence and predictors of musculoskeletal pain among Danish fishermen - results from a cross-sectional survey.

BACKGROUND: Fishermen work in a physically challenging work environment. The aim of this analysis was to estimate the prevalence and predictors of musculoskeletal pain among Danish fishermen. METHOD: A cross-sectional survey in a random sample of Danish fishermen was done with application of the Nordic questionnaire regarding musculoskeletal pain considering lower back, shoulders, hand neck, knee, upper back elbow, hip and feet. In total, 270 fishermen participated in the study (response rate: 28%). Workload, vessel type, skipper, duration of work, sideline occupation, days/weeks of fishing at sea, age, BMI and education were used as predictors for the overall musculoskeletal pain score (multiple linear regression) and for each single pain site (multinomial logistic regression). RESULTS: The prevalence of pain was high for all musculoskeletal locations. Overall, more than 80% of the responding Danish fishermen reported low back pain, which in 37% lasted for a minimum of 30 days during the past year. In the multiple linear regression analysis, middle workload was associated with a 32% (95% CI: 19-46%) and high workload with 60% (95% CI: 46-73%) increased musculoskeletal pain score compared to low work load. Multinomial logistic regression models showed that workload was the only predictor for all pain sites, in particular regarding upper and lower limb pain. CONCLUSION: Although changes were implemented to improve the fishermen's work environment, the work continues to be physically demanding and impacting their musculoskeletal pain. Potential explanation for this unexpected result like increased work pressure and reduced financial attractiveness in small scale commercial fishery needs to be confirmed in future research.

The metabolic syndrome among Danish seafarers: a follow-up study.

BACKGROUND: The metabolic syndrome (MS) represents a cluster of risk factors related to insulin resistance. Metabolic syndrome is a strong risk factor for chronic metabolic and cardiovascular diseases and is related to nutritional factors, sleep patterns, work-related stress, fatigue, and physical activity - all of which are critical issues at sea. We have previously demonstrated a MS prevalence of 24.2% in Danish seafarers. This study aimed to follow the trend of MS after 2 years' intervention. MATERIALS AND METHODS: Out of 524 Danish seafarers (mean age 37.7 years) who underwent medical fit-for-duty examination by seamen's doctors at baseline, 141 seafarers (mean age 41.3 years) were tracked and re-examined after 2 years. At baseline all participants received general advice regarding lifestyle issues. Seafarers with MS were additionally given specific advice regarding treatment. The seafarers provided questionnaire information about their workplace on board, about treatment of hyperlipidaemia, hypertension, and about previously diagnosed type 2-diabetes. In order to define MS, we collected data about waist circumference, blood pressure, triglycerides, HDL-cholesterol, and fasting plasma glucose. RESULTS: Out of 35 (26.5%) seafarers who fulfilled the criteria for MS at follow-up, 18 had MS at baseline while 9 were incident cases. Two seafarers with MS at baseline ceased to qualify for this condition at follow-up. The prevalence of seafarers with MS at follow-up represents a minimal estimate because a proportion could not be assessed due to missing fasting blood tests. Smoking and alcohol consumption was not reduced. CONCLUSIONS: In spite of the intervention, the prevalence of MS increased in this group of seafarers. This study indicates the limitations of individual health promotion and the need for corporate actions.

Occupational asthma in maritime environments: an update.

In 2006 we published our first review based on the available literature on occupational asthma in maritime environments in the "International Maritime Health" journal. Since then, we have obtained a great deal of new knowledge on asthma in seafood workers and fishermen and on the impact of exposures from sulphites preservatives, container fumigants etc. in maritime workers. This review aims to provide an update of the current knowledge base about occupational asthma in a maritime context and to provide recommendations regarding medical surveillance of workers at risk.

The workload of fishermen: a cross sectional survey among Danish commercial fishermen.

BACKGROUND: Fishery has always been perceived as a physically demanding industry of a manual character. In recent years the physical work environment has developed positively and consequently the current situation in not fully described in the existing literature. This study aims to describe the work environment of Danish fishermen with regard to their physical workload and ergonomic factors. MATERIALS AND METHODS: A cross sectional study was performed on a random sample of active Danish commercial fishermen (response rate: 28%) by means of a questionnaire on demographic and self-reported occupational and health data. Questions covering the physical workload were related to seven different work situations and a score summing up the workload was developed for the analysis of the relative impact on different groups of fishermen. RESULTS: Almost all fishermen (96.2%) were familiar to proper lifting techniques but only 55.4% used them in their daily work. Standing work was the most applied work position (81.8%), while repetitive hand and finger movements and twisting and bending in the back were other frequent work situations. Deckhands had higher workload scores than skippers, while crew on Danish seiners had higher workload scores than fishermen in other vessel types. CONCLUSIONS: Despite improved work environment in the Danish fishing industry, fishermen still experience high levels of workload and suboptimal ergonomic conditions, which are known to cause pain and impair musculoskeletal health. To address the specific areas of fishing with the highest workload, future investments in assistive devices to ease the demanding work and reduce the workload, should particularly address deckhands and less mechanized vessels.

Raynaud's Phenomenon in a Slap Bass Player: A Case Report.

OBJECTIVE: Secondary Raynaud's phenomenon is a frequent condition related to occupational exposure to local vibration but has not been described in musicians. This study aims to describe cold-induced blanching of the right second and (in particular) third digits in a 67-year-old double bass player following decades of cumulative repetitive blunt trauma to the fingers from slapping the strings. METHODS: A physical examination was undertaken and systolic blood pressure measured before and after cold provocation. RESULTS: At 10 deg C the brachial systolic blood pressure was 156 mm Hg while blood pressure was immeasurable at the finger level, corresponding to a finger/brachial index of 0% of the second and third fingers. CONCLUSION: This is the first reported case of objectively verified, playing-related Raynaud's phenomenon in a musician.

Clinical neurological examination vs electrophysiological studies: Reflections from experiences in occupational medicine.

Seventy-five percent of upper limb disorders that are related to work are regarded as diagnostically unclassifiable and therefore challenging to the clinician. Therefore it has been generally less successfully to prevent and treat these common and frequently disabling disorders. To reach a diagnosis requires the identification of the responsible pathology and the involved tissues and structures. Consequently, improved diagnostic approaches are needed. This editorial discusses the potentials of using the clinical neurologic examination in patients with upper limb complaints related to work. It is argued that a simple but systematic physical approach permits the examiner to frequently identify patterns of neurological findings that suggest nerve afflictions and their locations, and that electrophysiological studies are less likely to identify pathology. A diagnostic algorithm for the physical assessment is provided to assist the clinician. Failure to include representative neurological items in the physical examination may result in patients being misinterpreted, misdiagnosed and mistreated.

Seafarer fatigue: a review of risk factors, consequences for seafarers' health and safety and options for mitigation.

BACKGROUND: The consequences of fatigue for the health and safety of seafarers has caused concern in the industry and among academics, and indicates the importance of further research into risk factors and preventive interventions at sea. This review gives an overview of the key issues relating to seafarer fatigue. MATERIALS AND METHODS: A literature study was conducted aiming to collect publications that address risk factors for fatigue, short-term and long-term consequences for health and safety, and options for fatigue mitigation at sea. Due to the limited number of publications that deals with seafarers, experiences from other populations sharing the same exposures (e.g. shift work) were also included when appropriate. RESULTS: Work at sea involves multiple risk factors for fatigue, which in addition to acute effects (e.g., impaired cognition, accidents) contributes through autonomic, immunologic and metabolic pathways to the development of chronic diseases that are particularly prevalent in seafarers. CONCLUSIONS: Taking into account the frequency of seafarer fatigue and the severity of its consequences, one should look into the efficacy of the current legislative framework and the industry's compliance, the manning of the international merchant fleet, and optimised working, living and sleeping conditions at sea. Considering circumstances at sea, e.g. working in shifts and crossing time zones, that cannot be altered, further assessment of the potentials of preventive interventions including fatigue prediction tools and individual fatigue mitigation management systems is recommended.

Brachial plexopathy: a case-control study of the relation to physical exposures at work.

BACKGROUND: Work-related upper limb disorders constitute a diagnostic challenge. However, patterns of neurological abnormalities that reflect brachial plexus dysfunction are frequent in limbs with pain, weakness and/or numbness/tingling. There is limited evidence about the association between occupational physical exposures and brachial plexopathy. METHODS: 80 patients with brachial plexopathy according to defined criteria and 65 controls of similar age and sex without upper limb complaints were recruited by general practitioners. Patients and controls completed a questionnaire on physical and psychosocial work-exposures and provided psychophysical ratings of their perceived exposures. The exposures of cases and controls were compared by a Wilcoxon rank sum test. Odds ratios and dose-response relationships were studied by logistic regression. RESULTS: Whether assessed as the extent during the workday or days/week, most physical exposures, in particular upper limb posture and repetition, were significant risk indicators with clear dose-response relationships. These findings were supported by psychophysical responses that also identified perceived work pace and the use of force as risk indicators. The identified psychosocial relations were limited to measures reflecting physical exposures. CONCLUSIONS: While the identified risk indicators have previously been associated to upper limb symptoms as well as to diagnosed disorders other than brachial plexopathy, this study indicates an association between physical and work-exposures and brachial plexopathy. Longitudinal studies should be conducted in order to exclude bias from information and selection, both of which may occur with the applied case-control design.

[Bilateral hypothenar hammer syndrome]. / Bilateralt hypothenarhammersyndrom.

Hypothenar hammer syndrome is caused by ulnar artery occlusion subsequent to repeated blunt trauma such as by using the hypothenar as a hammer during work. Allen's test permits the detection of this frequent and often overlooked cause of hand pain and ischaemia. The four bilateral hypothenar hammer syndromes described in this case report occurred after several years of occupational exposure to hard shocks/impacts to the hypothenar from workpieces, which were held with a firm grip.

The influence of vessel movements on the energy expenditure of fishermen in relation to activities and occupational tasks on board.

BACKGROUND: Previous studies of professional fishing activities have indicated that vessel movements correlate to fishermen's energy expenditure. We have previously demonstrated that even in calm weather, the heel and pitch significantly increase the fishermen's energy expenditure, ignoring the activities carried out on board. This continuation of the study goes further by exploring the relation between the exposure to the ship's movements and the fishermen's energy expenditure during various physical activities on board. MATERIALS AND METHODS: Four fishermen on 2 contemporary steel trawlers recorded their work activities on an hourly basis during a 4 days fishing voyage. The energy expenditure was estimated with a body monitoring system (SenseWear Pro 3) carried as an armband, placed on the right upper arm. The vessels' movements were assessed by a gyroscope placed in the wheelhouse. The additional energy expenditure relative to the energy expenditure during sleep was recorded during activities such as navigation, fishing, and machine handling and was correlated to the vessels' recorded movements (pitch/roll). Data were analysed by linear regression. RESULTS: Roll and pitch were less than 10o for both vessels during the voyages. The fishermen's energy expenditure differed with the tasks undertaken and correlated with the vessels' movements, but for navigation and fishing the correlation was only significant in the highest - fourth quartile of - pitch/roll. CONCLUSIONS: This study has demonstrated that vessel's movements in calm weather increase the energy expenditure during navigation, fishing, and machine handling and that the relation differs in between these activities on board and rest.

Exposures and health effects at sea: report on the NIVA course: maritime occupational medicine, exposures and health effects at Sea Elsinore, Denmark, May 2014.

The presentations and discussions summarised provide an overview on the current state of knowledge on a wide range of occupational health risks to which seafarers are exposed. The definition of an occupational risk for a seafarer poses problems as their ship provides both their working and their living environment and, because of its mobility, can expose them to diverse climatic and infectious risks. Knowledge about levels of exposure to potential health risks in seafarers is limited when compared to those working ashore while, because of a pattern of working that is often temporary and insecure, there is little valid long-terminformation on ill-health that can be related to risks at sea and in port. The data that do exist mainly come from developed countries, especially those in North Western Europe and extrapolation from these populations to the Asian seafarers who now crew most ships is of uncertain validity.This course, run by the NIVA Foundation and supported financially by the Nordic Council of Ministers, provided a first opportunity to draw a wide range of information and experience together to review exposure and health risks in seafarers. As a result it provided both a forum for deciding on future needs for investigation and gave those attending a range of insights that can help inform their own practices.

Occupational accidents in the Danish merchant fleet and the nationality of seafarers.

BACKGROUND: The aim of the study was to examine occupational accidents reported from non-passenger merchant ships registered in the Danish International Ship Register in 2010-2012, with a focus on analysing nationality differences in the risk of getting injured in an accident. METHODS: Data about notified occupational accidents were collected from notifications sent to the Danish Maritime Authority and from records of contact with Danish Radio Medical. Events were matched by personal identification and accident data to create a unified database. Stratified cumulative time spent on board by seafarers was used to calculate accident rates. Incidence rates of different nationalities were compared by Poisson regression. RESULTS: Western European seafarers had an overall accident rate of 17.5 per 100000 person-days, which proved to be significantly higher than that of Eastern European, South East Asian and Indian seaman (adjusted incidence rate ratio 0.53, 0.51 and 0.74, respectively), although differences decreased over the investigated period. Smaller but in most cases still significant discrepancies were observed for serious injuries. The back injury rate of Western European employees was found especially high, while eye injuries seem to be more frequent among South East Asian workers. CONCLUSIONS: The study identified substantial differences between nationalities in the rate of various accidents reported from merchant ships sailing under the Danish flag. The differences may be attributed to various factors such as safety behaviour. Investigation of special injury types and characterisation of effective elements of safety culture can contribute to the improvement of workplace safety in the maritime sector.

Vibration on board and health effects.

There is only limited knowledge of the exposure to vibrations of ships' crews and their risk of vibration-induced health effects. Exposure to hand-arm vibrations from the use of vibrating tools at sea does not differ from that in the land-based trades. However, in contrast to most other work places, seafarers are also exposed to vibrations to the feet when standing on vibrating surfaces on board. Anecdotal reports have related the development of "white feet" to local exposure to vibration, e.g. in mining, but this connection has not been investigated in the maritime setting. As known from studies of the health consequences of whole body vibrations in land-transportation, such exposure at sea may affect ships' passengers and crews. While the relation of back disorders to high levels of whole body vibration has been demonstrated among e.g. tractor drivers, there are no reported epidemiological evidence for such relation among seafarers except for fishermen, who, however, are also exposed to additional recognised physical risk factors at work. The assessment and reduction of vibrations by naval architects relates to technical implications of this impact for the ships' construction, but has limited value for the estimation of health risks because they express the vibration intensity differently that it is done in a medical context.

Health of Danish seafarers and fishermen 1970-2010: What have register-based studies found?

BACKGROUND: This study aimed to review Danish register-studies on seafarers' and fishermen's health and safety. METHODS: Register-based or register-linked studies from 1970 until 2012 were identified and reviewed. Four categories of studies were included: mortality, hospitalization, specific diagnoses and conditions and accidents. Standardized risks estimates were typically calculated by comparison with the total Danish working population. RESULTS: Elevated rates were found in all four categories. For mortality male seafarers had excess rates of accidents, cirrhosis of the liver, cancer, and suicides, and fishermen of accidents and cardiovascular disorders. Female seafarers in male-dominated occupations also had increased mortality rates. Elevated hospitalization rates for male seafarers were particularly prominent for endocrine/nutritional conditions, cervical discopathy, gastrointestinal and cardiovascular diseases, cancers, hearing impairment, and injuries, and for female seafarers cancers, circulatory and genitourinary diseases and injuries. Fishermen had increased hospitalization rates for cardiovascular diseases, bronchitis, emphysema, lung cancer, gonarthrosis, thoracolumbar discopathy, rotator cuff syndrome, carpal tunnel syndrome, injuries and hearing impairment. Specific diagnoses and conditions: There was an elevated risk of tuberculosis, hepatitis B and certain cancers for male seafarers, and of obesity and occupational accidents for both fishermen and seafarers. CONCLUSIONS: In spite of safety measures and significant structural changes in the Danish merchant and fishing fleet, the spectrum of health indicators continues to indicate considerable risk factors in the maritime environment and/or the lifestyle of seafarers and fishermen. Future monitoring of fishermen's and seafarers' health will remain essential for implementing appropriate preventive measures.

Can testing of six individual muscles represent a screening approach to upper limb neuropathic conditions?

BACKGROUND: It has previously been demonstrated that an extensive upper limb neurological examination of individual muscle function, sensation in homonymous innervated territories, and nerve trunk allodynia is reliable and that the outcome reflects symptoms. Since this approach may appear complicated and time consuming, this study deals with the value of an examination limited to manual testing of only six muscles. METHODS: Two examiners blinded to symptom status performed manual muscle testing of six muscles in 82 upper limbs with or without pain, weakness, and/or numbness/tingling. The six muscles represent three antagonist pairs (pectoralis major/posterior deltoid, biceps/triceps, and radial flexor of wrist/short radial extensor of wrist). The inter-rater reliability of detecting muscular weaknesses and the relation of weakness to the mentioned symptoms were analysed by kappa-statistics. RESULTS: The two examiners recognized weaknesses in 48 and 55 limbs, respectively, with moderate agreement (median kappa = 0.58). Out of these, 35 and 32 limbs, respectively, were symptomatic. There was good correlation between findings and symptoms for one examiner (kappa = 0.61) and fair correlation for the other one (kappa = 0.33). Both reached high sensitivity (0.92, 0.84) but less satisfactory specificity (0.70, 0.50). Weaknesses agreed upon by the two examiners correlated moderately with symptoms (kappa = 0.57). CONCLUSIONS: Weakness in one or more muscles was present in almost all symptomatic limbs but in many non-symptomatic limbs as well. Manual testing of six muscles may represent a useful screening approach to upper limb neuropathic conditions, but a confirmative diagnosis requires further assessment.