[Premapping of risks: guide to inspection by occupational physician]. / Premappatura dei rischi: guida al sopralluogo del medico competente.

Art. 25 of Law Decree 81/08 sets obligation for occupational physician to collaborate with employer for risk assessment (also in view of health surveillance planning) and to inspect "workplaces at least once a year or at different times according to risk assessment". Hence, collaboration to risk assessment, periodical inspection at workplace and definition of health surveillance protocols are extremely important in occupational physician's activity also in view of preventive effectiveness. An easily readable information technology tool is developed, in the frame of the most recent WHO activities: a toolkit for rapid and complete identification of the presence of possible risk inductors. This tool, already tested in several crafts, can be easily used also by occupational physician during periodical inspection.

[Working hypothesis of simplified techniques for the first mapping of occupational hazards in handicraft. First part: ergonomics hazards]. / Ipotesi di tecniche semplificate per la prima mappatura dei rischi professionali nel settore artigiano. Prima parte: rischi legati all'ergonomia.

During the last Congress of the International Ergonomics Association (IEA), Beijing - China August 2009, in collaboration with World Health Organization an international group for developing a "toolkit for MSD prevention" was founded. Possible users of toolkits are: members of a health and safety committee; health and safety representatives; line supervisors; foremen; workers; government representatives; health workers implementing basic occupational health services; occupational health and safety specialists. According with ISO standard 11228 series and their ISO Application document for the Key enters and Quick Assessment (green/red conditions), our group developed a first mapping methodology of occupational hazards in handicraft, working with the support of the information technology (Excel). This methodology, utilizing specific key enters and quick evaluation, allows a simple risk estimation. So it is possible to decide for which occupational hazards will be necessary an exhaustive assessment and to which professional consultant it is better to direct them to (worker's doctor, engineer, chemical, etc.).

Updating reference values and predictive models of the OCRA method in the risk assessment of work-related musculoskeletal disorders of the upper limbs.

A database has been established combining existing data for 23 groups of workers with different level of exposure to repetitive movements of the upper limbs. For all groups, data were available regarding an exposure index (OCcupational Repetitive Actions - OCRA index) and clinically determined UL-WMSDs outcomes (PA = Prevalence of workers affected by one or more UL-WMSDs; PC = Prevalence of single diagnosed cases of an UL-WMSDs). Using these data, new critical values of the OCRA index have been estimated for discriminating different exposure levels (green, yellow, red areas) and new forecasting models of expected PA and PC in exposed populations based on OCRA exposure indexes. The new critical values of the OCRA index were estimated by an original approach in which data for the effect variable (PA) in a reference population not exposed to the relevant risks are combined with the regression function between OCRA and PA. The best simple regression functions between OCRA exposure indexes and health outcomes variables (PA; PC) were researched to obtain forecasting models of effects starting from exposure. Discussion of the results obtained considers their intrinsic limitations, as they are based on prevalence studies, as well as providing recommendations and cautions in the use of the proposed classification system and forecasting models when the OCRA method is applied.

Exposure assessment of upper limb repetitive movements: a consensus document developed by the Technical Committee on Musculoskeletal Disorders of International Ergonomics Association (IEA) endorsed by International Commission on Occupational Health (ICOH).

This consensus document intends to supply a set of definitions, criteria and procedures useful to describe and, wherever possible, to assess the work conditions that can represent a physical overload for the upper limbs. The document is aimed at all the operators, i.e. occupational doctors but mainly technicians, who are, involved in risk exposure assessment and management. The document intends to provide methods and procedures easily applicable in the field, possibly not requiring sophisticated instrumentation and when possible based on observation procedures. The proposed methods shall be based as far as possible on knowledge and data from scientific literature: should they be contradictory or deficient, reference will be made to standards or pre-standards issued by national and international agencies and bodies, with the experience of researchers involved and common sense. In this regard, it is to be emphasized that the potential users increasingly demand an easily applicable method for description and assessment of work with repetitive movements. The group intends to give a response even if there are still uncertainties from a strictly scientific standpoint: however the group commits itself to perform subsequent validations especially of as yet unconsolidated issues. This document focuses specifically on identification of risk factors and describes some of the methods that have been developed for evaluating them. There is a rapidly developing body of literature on job analysis and not yet agreement on a single best way to analyze jobs. Professional judgement is required to select the appropriate methods. Analysis and design of jobs should to be integrated into an ongoing ergonomics program that includes management commitment, training, health surveillance, and medical case management. In summing up this report, space must be given to the check lists that are so often seen in the medical press, although this is not the occasion to propose a detailed analytical review.

[Aging at work and musculoskeletal disorders]. / Invecchiamento lavorativo ed alterazioni muscoloscheletriche.

By means of a critical review of the international literature and of their own published experiences, the Authors discuss the influence of the "age" factor on work related musculoskeletal disorders of the spine and upper limbs. Regarding the spine, the lumbosacral spine in particular, there is evidence (both in relation to pathways and from epidemiological data) of the influence of age in determining a progressive increase in the occurrence of spondyloarthropathy with clear radiological signs. For upper limb disorders the influence of the "age" factor is still under debate and in any case does not seem of great importance. As far prevention is concerned for elderly workers subject to fixed postures and repetitive movements of the upper limbs it seems sufficient, to adopt the general measures used for the whole working population. However, specific measures should be adopted for elderly workers exposed to manual material handling (MMH). These consist in using reference values for the recommended weight that are lower than those adopted for younger workers (aged 18-45 years) and in implementing specific programs of active health surveillance.

[Proposal and preliminary validation of a check-list for the assessment of occupational exposure to repetitive movements of the upper lims]. / Proposta e validazione preliminare di una check-list per la stima dell'esposizione lavorativa a movimenti e sforzi ripetuti degli arti superiori.

Over the last few years the Authors developed and implemented, a specific check-list for a "rapid" assessment of occupational exposure to repetitive movements and exertion of the upper limbs, after verifying the lack of such a tool which also had to be coherent with the latest data in the specialized literature. The check-list model and the relevant application procedures are presented and discussed. The check-list was applied by trained factory technicians in 46 different working tasks where the OCRA method previously proposed by the Authors was also applied by independent observers. Since 46 pairs of observation data were available (OCRA index and check-list score) it was possible to verify, via parametric and nonparametric statistical tests, the level of association between the two variables and to find the best simple regression function (exponential in this case) of the OCRA index from the check-list score. By means of this function, which was highly significant (R2 = 0.98, p < 0.0000), the values of the check-list score which better corresponded to the critical values (for exposure assessment) of the OCRA index looked for. The following correspondance values between OCRA Index and check-list were then established with a view to classifying exposure levels. The check-list "critical" scores were established considering the need for obtaining, in borderline cases, a potential effect of overestimation of the exposure level. On the basis of practical application experience and the preliminary validation results, recommendations are made and the caution needed in the use of the check-list is suggested.

[The assessment of the risk due to the manual lifting of patients: the initial descriptive and analytical results on exposure levels]. / Valutazione del rischio da movimentazione manuale di pazienti: primi risultati descrittivi e analitici sui livelli di esposizione.

The paper reports the results of risk evaluation of patient lifting or moving obtained from a multicentre study on 216 wards, for both acute hospital patients and in geriatric residences. In all situations the exposure to patient lifting was assessed using a concise index (MAPO). Analysis of the results showed that only 9% of the workers could be considered as exposed to negligible risk (MAPO Index = 0-1.5); of these 95.7% worked in hospital wards and only 4.3% in geriatric wards. A further confirmation of the higher level of exposure of workers in long-term hospitalization was that 42.3% were exposed to elevated levels (MAPO Index > 5) compared with 27.7% observed in hospital ward workers. The mean values of the exposure index were 6.8 for hospital wards and 9.64 for geriatric residences and, although much higher in the latter, both categories showed high exposure. In the orthopaedic departments of the hospitals the values were higher than in the geriatric wards (MAPO Index = 10.1); medical and surgical departments showed values similar to the mean values observed in the geriatric wards. These high values were due to: severe shortage of equipment life lifting devices (95.5%) and minor aids (99.5%), partial inadequacy of the working environment (69.2%), poor training and information (96.1% lacking); only the supply of wheelchairs was adequate (65.8%). All of which points to an almost generalized non-observance of the regulations listed under Chapter V of Law No. 626/94. However, the proposed method of evaluation allows anyone who has to carry out prevention and improvement measures to identify priority criteria specifically aimed at the individual factors taken into consideration. By simulating an intervention for improvement aimed at equipment and training, 96% of the wards would be included in the negligible exposure class (MAPO Index 0-1.5).

[Clinical studies in health workers employed in the manual lifting of patients: methods for the examination of spinal lesions]. / Studi clinici negli operatori sanitari addetti alla movimentazione manuale di pazienti: metodi per la rilevazione delle affezioni del rachide.

To enable different research groups to make a standardized collection of clinical data on alterations of the lumbar region of the spine, protocols were used for the collection and classification of data that were proposed and thoroughly validated by the authors. The protocols include a clinical/functional examination of the spine, checking for positive anamnestic threshold, for pain on pressure/palpation of the spiny apophyses and paravertebral muscles, for painful movements, in order to classify 1st, 2nd and 3rd grade functional spondylarthropathy (for different regions of the spine). An ad hoc questionnaire was also prepared for the quantitative and qualitative study of true acute low back pain and the ingravescent low back pain controlled at the onset pharmacologically. The results of this questionnaire make it possible to calculate the incidence of acute low back pain (true and pharmacologically controlled).

[Initial epidemiological data on the clinical effects in health workers employed in the manual lifting of patients in wards]. / Primi dati epidemiologici sugli effetti clinici negli operatori sanitari addetti alla movimentazione manuale di pazienti nei reparti di degenza.

An investigation was carried out by teams from various centres coordinated by the EPM (Ergonomics of Posture and Movement) Research Unit on 54 different hospitals in various regions of northern and central Italy. The teams examined a total of 3341 health workers whose job involved manual handling of patients (553 male and 2788 females, 1568 working in hospitals and 1773 in geriatric residences). Numerous meetings were held to ensure that the methods of assessing the exposure indexes and spinal impairment were identical in the various teams. The final data were processed centrally at the EPM Research Unit. The sample analyzed may be considered as representative of the situation in hospitals in Italy, at least for northern and central Italy. The mean age was 36 years, mean length of service in the department 6 years and mean length of job duration not exceeding 10 years; staff turnover was high. Physical examination revealed that 8.4% of the workers had had at least one episode of acute low back pain in the previous 12 months: i.e., 4 times the values of the reference groups. Also in the case of clinical-functional spondyloarthropathies of the lumbosacral spine, in the females there was a significantly higher prevalence than in the reference groups. All disorders were more severe in sectors more at risk, i.e., old peoples homes, rehabilitation centres, orthopaedic and surgical departments, and in any case higher in old peoples homes and geriatric residences. The initial data concerning the ratio between presence of spinal disease and risk index were also positive.

[The application of a synthetic index of exposure in the manual lifting of patients: the initial validation experiences]. / L'applicazione dell'indice sintetico di esposizione nella movimentazione manuale pazienti: prime esperienze di validazione.

Via a multicentre study coordinated by the EPM research group carried out in 216 wards in a total of 56 hospitals, old peoples homes and geriatric departments, it was possible to quantify exposure to patient handling (classified in 4 classes: 0-1.5 negligible, 1.51-5 slight to average, 5.01-10 average to high, > 10 elevated), and at the same time identify the damage to the lumbosacral spine thus caused. Both assessment of exposure and identification of health impairment were carried out using homogeneous methods. Subjects with work seniority in the job of less than 6 months and subjects who had been transferred because of back trouble were excluded from the study. It was therefore possible to carry out two types of study to assess the association between exposure and impairment. In study A, covering 3021 subjects, an analysis was performed of the association between exposure index, positive response to the anamnestic threshold for lumbosacral disorders and acute low back pain using the method of logistic analysis to obtain the prevalence odds ratios. In study B, covering 418 subjects, the analysis of association was performed on the incidence rates of episodes of acute low back pain and pharmacologically controlled acute low back pain, assuming that exposure in the wards had remained constant. The technique used was Poisson regression, thereby calculating the relative incidence rate ratios. Both for PORs and IRRs the reference group consisted of the exposure class judged as negligible (exposure index 0-1.5). The results showed that the PORs calculated for positive lumbar threshold were significant for increasing exposure classes with a positive trend for the second and third exposure class but not for the last, presumably due to a healthy worker selection effect. Neither in Study A nor in Study B were any associations observed between exposure and acute low back pain occurring in the previous 12 months: this may be due to the fact that the impairment indicator does not appear to be appropriate in terms of latency period. A different result was obtained in Study B which showed a good association between exposure and incidence rates of episodes of acute low back pain and pharmacologically controlled acute low back pain according to department. The IRRs showed a positive trend both for acute episodes (IRR: 1.932, 2.439, 2.847) and for acute plus pharmacologically controlled acute episodes (1.798, 1.830, 4.523). On the basis of these results, even with the caution required for the reasons explained in the text, it seems to be possible to identify three grades of exposure which correspond to increasing probability of impairment of the lumbosacral region of the spine: the first where risk seems negligible corresponds to an exposure level between 0 and 1.5. The second, where the episodes of low back pain may occur with an incidence 3.8 times greater, corresponds to an exposure level between 1.51 and 5, and the third corresponds to exposure levels exceeding 5, where the episodes of low back pain may occur with an incidence up to 5.6 times greater than expected.

[Worker turnover because of spinal pathologies in the wards and outpatient clinics of the hospitals of Leno and Manerbo, Brescia]. / Il turn-over, per patologie del rachide, dei lavoratori nei reparti di degenza e negli ambulatori degli ospedali di Leno e Manerbio (BS).

A total of 306 employees of the hospitals of the Leno/Manerbio health area underwent clinical and anamnestic examination in order to ascertain the existence of degenerative diseases of the spine associated with "manual handling of loads" risk. The prevalences obtained for positive anamnestic threshold concerning the lumbosacral spine, the trend of total acute low back pain and of low back pain in the last year showed lower values compared to the entire national group and in any case lower or only slightly above the values for the reference group of non-exposed subjects. Therefore, in order to assess the real prevalences of disorders due to incorrect load handling in hospital environments, it is important to assess the presence of associated disorders of the spine also and especially in outpatients departments. In fact, unsuitable or unfit staff had recently been transferred from the wards to outpatients departments. 56 workers from outpatients departments underwent physical-anamnestic examination: 16 workers (4.5% of the entire group under study) from average-to-high risk wards were identified as suffering from degenerative disorders of the lumbosacral spine. Therefore the prevalence of unfit subjects from hospital wards, cancelling the effect of the turnover factor on outpatients departments, led to an almost twofold total frequency, which rose from 6.9% to 11.4%.

[Acute lumbago due to the manual lifting of patients in wards: prevalence and incidence data]. / La lombalgia acuta da movimentazione manuale di pazienti nei reparti di degenza: dati di prevalenza e incidenza.

The aim of the study was to measure the occurrence (prevalence and incidence) of episodes of acute low back pain (definite effect) in a wide sample of health workers assisting disabled patients. A questionnaire was used for the study both of true acute low back pain and of episodes of ingravescent low back pain controlled pharmacologically at the onset. The questionnaire identified overall acute and pharmacologically controlled episodes occurring in the previous 12 months, both in the course of work and over the whole life of the subject. Appropriately trained operators administered the questionnaire to 551 subjects; 481 valid answer cards were obtained from 372 females and 109 males working in medical, orthopaedic and geriatric departments. 75.4% of the sample had high exposure index levels for patient lifting. The prevalence of true acute low back pain was 9% in males and 11% in females referred to the previous 12 months. Taking acute true and pharmacologically controlled low back pain together the prevalences rose to 13.8% for males and 26.9% in females. Data from the reference populations showed that acute low back pain did not exceed 3% on average in the previous year. Since work seniority in the hospital wards was known, the incidences were calculated, giving 7.9% in females and 5.29% in males for acute low back pain, and 19% in females and 3.49% in males for pharmacologically controlled low back pain. Considering the number of episodes in 100 workers/year, acute low back pain alone reached prevalences of 13-14%. This therefore appears to confirm the positive ratio between episodes of low back pain and duties involving assistance to disabled patients.

An observational method for classifying exposure to repetitive movements of the upper limbs.

This article presents and discusses a model for describing and evaluating the principal risk factors characterizing occupational exposure: frequency and repetitiveness of movements; use of force; type of posture and movements; distribution of recovery periods; and presence of other influential (additional) factors. For each risk factor, the author proposes a method of practical detection in the field, as well as criteria for classifying and interpreting the results based on a critical review of the available literature on the subject. Numerous examples are supplied to better illustrate the concepts presented. The various factors considered are classified using numbers or indexes, so that they can be integrated into a concise exposure index.

Guidelines for designing jobs featuring repetitive tasks.

Preventive measures aimed at minimizing the occurrence of work-related musculoskeletal disorders of the upper limbs (WMSDs) associated with repetitive tasks can be divided into three categories: structural, organizational and educational. Whenever specific risk and injury assessments have shown the need for preventive action, this is most often implemented within the framework of a range of assorted measures. In particular, structural measures involve optimizing the layout of the work area and furnishings, and the 'ergonomic' properties of work tools and equipment. Such measures serve to alleviate the problems caused by the use of excessive force and awkward postures. The authors refer to the principles guiding such structural measures, in the light of the extensive literature that has been published on the subject. Organizational (or reorganizational) measures essentially relate to job design (i.e. distribution of tasks, speeds and pauses). They serve to alleviate problems connected with highly repetitive and frequent actions, excessively lengthy tasks and inadequate recovery periods. Very few relevant findings are available: the authors therefore illustrate in some detail a practical trial conducted in a major engineering firm. The objective was to lower to acceptable limits the frequency of certain repetitive tasks performed using the upper limbs. The trial made it possible to identify a suitable plan and schedule of measures taking into due consideration the impact of the plan on production levels (and costs). The fundamental principles guiding the adoption of specific educational and training programmes for the workers and their supervisors are presented and discussed.

Manual handling of loads: the point of view of experts involved in the application of EC Directive 90/269.

This paper illustrates the viewpoint of a group of Italian research workers who have been directly involved in providing criteria and guidelines for application of EC Directive 90/269, Manual handling of loads. The problems posed by application of the Directive in Italy and which are mainly related to exposure assessment, health surveillance and risk management (work and workplace redesign) are thoroughly examined. Major questions still to be solved include defining methods for assessment of multiple and complex load handling tasks, identifying data sources on 'health effect' trends as investigated in a working population with low exposure or in the general population in order to fix action levels, and setting up a data bank of technical and organizational solutions and products accessible to experts and users.

[Musculoskeletal disorders of upper extremities caused by biomechanical overload: methods and criteria for the description of occupational exposure]. / Alterazioni muscolo-scheletriche degli arti superiori da sovraccarico biomeccanico: metodi e criteri per l'inquadramento dell'esposizione lavorativa.

This article presents and discusses a model for describing and evaluating the principal risk factors characterising occupational exposure: frequency and repetitiveness of movements, use of force, type of posture and movements, distribution of recovery periods, presence of other influential (complementary) factors. For each risk factor, the authors propose a method of practical detection in the field, as well as criteria for classifying and interpreting the results based on a critical review of the available literature on the subject. Numerous examples are supplied to better illustrate the concepts presented. The various factors considered are classified using numbers or indexes, so that they can be integrated into a concise exposure index described by the authors elsewhere in this volume.

[Proposal of a concise index for the evaluation of the exposure to repetitive movements of the upper extremity (OCRA index)]. / Proposta di un indice sintetico per la valutazione dell'esposizione a movimenti ripetitivi degli arti superiori (OCRA index).

In the light of data and speculation contained in the literature, and based on procedures illustrated in a previous research project in which the authors describe and evaluate occupational risk factors associated with work-related musculoskeletal disorders of the upper limbs (WMSDs), this article proposes a method for calculating a concise index of exposure to repetitive movements of the upper limbs. The proposal, which still has to be substantiated and validated by further studies and applications, is conceptually based on the procedure recommended by the NIOSH for calculating the Lifting Index in manual load handling activities. The concise exposure index (OCRA index) in this case is based on the relationship between the daily number of actions actually performed by the upper limbs in repetitive tasks, and the corresponding number of recommended actions. The latter are calculated on the basis of a constant (30 actions per minute) which represents the action frequency factor, and is valid-hypothetically-under so-called optimal conditions; the constant is diminished case by case (using appropriate factors) as a function of the presence and characteristics of the other risk factors (force, posture, complementary elements, recovery periods). Although still experimental, the exposure index can be used to obtain an integrated and concise assessment of the various risk factors analysed, and to classify occupational scenarios featuring significant and diversified exposure to such risk factors.

[Clinical studies in working populations: a model for the anamnestic investigation of the pathology of the upper limbs and its practical application]. / Studi clinici in popolazioni lavorative: un modello per l'indagine anamnestica delle patologie degli arti superiori e sue modalità applicative.

Following a brief review of the principal clinical characteristics of musculo-skeletal disorders of the upper limbs, the authors propose a protocol for a structured anamnestic examination featuring a series of set questions. The anamnestic model is based on a detailed listing of the symptoms to be analysed, which are divided into four categories: pain, paraesthesia, symptoms attributable to hyposthenia, and neurovegetative disorders. Regarding pain and paraesthesia, the authors list the localisation, pattern of onset, duration and number of episodes, irradiation, and treatment. The patients can thus be classified as anamnestic cases based on the following criteria: presence of pain or paraesthesia during the last 12 months, with episodes lasting for at least one week, or occurring at least once a month, with no previous acute trauma. For hyposthenia, the authors report on the conditions under which the disorder may develop. The neurovegetative disorders considered are modifications in colour of the fingers and reaction to exposure to low temperatures. The structure of the proposed anamnestic chart permits all findings to be easily encoded for subsequent storage in a dedicated database. The Appendix contains an annotated facsimile of the anamnestic chart.

[Clinical studies in working populations: value and significance of anamnestic findings, clinical tests and instrumental tests for the diagnosis of musculoskeletal disorders of the upper extremities]. / Studi clinici in popolazioni lavorative: valore e significato dei rilievi anamnestici, dei test clinici e degli esami strumentali per la diagnosi delle affezioni muscolo-scheletriche degli arti superiori (WMSDs).

The authors discuss the value and significance of symptoms in WMSDs, considering that the anamnestic threshold proposed in epidemiological investigations cannot be used as clinical and diagnosing criteria. Some useful clinical procedures are suggested for cases where there is a suspicion of musculo-skeletal disorders of the cervical spine and upper limbs, bearing in mind that they are to be applied within the framework of health surveillance programmes undertaken by health care practitioners who are not specialists in orthopaedics, physiatrics or neurology. The recommendations for instrumental tests and specialist referrals are also discussed for the various disorders. The authors also provide flow charts for the diagnostic procedures pertaining to WMSDs. The Appendix shows a sample patient chart illustrating the proposed procedures; it also permits the findings to be encoded so that they can be stored in a dedicated database. The codes for diagnosing WMSDs are also reported for the same epidemiological purposes.

[Occurrence of musculoskeletal disorders in working populations not exposed to repetitive tasks of the upper arms]. / L'occorrenza delle alterazioni muscolo-scheletriche in popolazioni lavorative non esposte a compiti ripetitivi degli arti superiori.

A total of 749 workers (males: 139 aged between 15 and 35 years, and 171 aged over 35 years; females: 176 aged between 15 and 35 years, and 263 aged over 35 years) performing tasks not at risk for work-related musculo-skeletal disorders of the upper limbs (WMSDs) underwent a clinical examination using a standardised method. The "anamnetics cases" were defined on the basis of pain or paraesthesia present for at least one week during the previous 12 months, or appearing at least once a month, and not subsequent to acute trauma. The anamnestic cases among the males amounted to 4.4% (age 15 divided by 35 years) and 12.3% (age > 35); among the females 4.6% (age 15 divided by 35 years) and 14.2% (age > 35). Of the 1498 limbs examined, the prevalent pathologies reported were: suspect narrow chest syndrome: 0.3% among the males > 35 years, 0.6% among the females aged 15 divided by 35 years, 1% among the females > 35 years; scapulo-humeral periarthritis: 0.3% among the males aged > 35 years, 0.3% among the females aged 15 divided by 35 years, 1.3% among the females aged > 35 years; lateral epicondylitis: 0.3% among the males aged > 35 years, 0.2% among the females aged > 35 years; trapezio-metacarpal arthrosis: 0.8% among the females aged > 35 years; wrist-hand tendinitis: 0.9% among the males aged > 35 years, 0.9% among the females aged 15 divided by 35 years; carpal tunnel syndrome: 2.5% among the females aged > 35 years. No disorders were detected outside of the age ranges indicated. Several workers reported more than one disorder. The number of workers with at least one WMSD was: males 0% in the 15 divided by 35 years age range, 3.5% in the > 35 year age range; females 2.3% in the 15 divided by 35 year age range, 7.2% in the > 35 year age range; 3.9% of the total sample population. The prevalences were on average quite low, particularly among the older workers, hence the authors recommend that even minimal prevalences detected in particular work environments should not be underestimated.