French good practice guidelines for management of the risk of low back pain among workers exposed to manual material handling: Hierarchical strategy of risk assessment of work situations.

BACKGROUND: Manual material handling remains a major cause of occupational accidents and diseases in various sectors and occupations. OBJECTIVE: This paper summarizes the main recommendations of the good practice guidelines of the French Society of Occupational Medicine for the risk assessment for back disorders in workers exposed to manual handling of loads. METHODS: The guidelines were written by a multidisciplinary working group of 24 experts, according to the Clinical Practice Guidelines method proposed by French National Health Authority, and reviewed by a multidisciplinary peer review committee of 50 experts. Recommendations were based on a large systematic review of the international literature carried out from 1990 to March 2012 and classified (Grade A, B, C or expert consensus) according to their level of evidence. RESULTS: The main recommendations are a three-level hierarchical method of risk assessment based on participatory ergonomics and suggested assessment tools that can be used routinely by professionals of occupational health, workers themselves and their supervisors. CONCLUSION: These French guidelines are intended for professionals of occupational health in charge of the prevention of low back disorders. The recommended methods are applicable to other countries than France.

Cardio-respiratory and subjective strains sustained by paraplegic subjects, when travelling on a cross slope in a manual wheelchair (MWC).

The aim of this study was to quantify cardiac, energetic and subjective strains during manual wheelchair (MWC) travel on cross slopes (Cs). 25 paraplegics achieved eight 300 m propulsion tests combining 4 Cs (0, 2, 8 and 12%) and 2 velocities (Vi = 0.97 m s(-1), Vc "comfortable"). Heart rate and oxygen uptake were recorded continuously. Subjective rating (RPE) was made on completion of each test. Vc exceeds Vi for all Cs. Cardiac and energetic strains at Vc also exceed those at Vi (p < 0.01). Mean cardiac cost (in bpm) at Vc is 34 (SD = 13) bpm for a 0/2% Cs and 55 (18) bpm for a 12% Cs. Mean energetic cost (in J m(-1) kg(-1)) is 1.20 (0.38) and 2.76 (0.97) for respectively 0/2% and 12% Cs at Vi and, at Vc 1.50 (0.43) and 3.37 (1.43) for 0/2% and 12% Cs respectively. Subjective rating was considered as moderate for a 12% Cs. MWC users with high level injuries travel faster as those with low level injuries. Strain increase is linear for Cs from 0% to 12%. The results suggest that 2% Cs is generally acceptable, while 8% would be a critical threshold.

Fuzzy-TLX: using fuzzy integrals for evaluating human mental workload with NASA-Task Load indeX in laboratory and field studies.

The aim of this study was to assess mental workload in which various load sources must be integrated to derive reliable workload estimates. We report a new algorithm for computing weights from qualitative fuzzy integrals and apply it to the National Aeronautics and Space Administration -Task Load indeX (NASA-TLX) subscales in order to replace the standard pair-wise weighting technique (PWT). In this paper, two empirical studies were reported: (1) In a laboratory experiment, age- and task-related variables were investigated in 53 male volunteers and (2) In a field study, task- and job-related variables were studied on aircrews during 48 commercial flights. The results found in this study were as follows: (i) in the experimental setting, fuzzy estimates were highly correlated with classical (using PWT) estimates; (ii) in real work conditions, replacing PWT by automated fuzzy treatments simplified the NASA-TLX completion; (iii) the algorithm for computing fuzzy estimates provides a new classification procedure sensitive to various variables of work environments and (iv) subjective and objective measures can be used for the fuzzy aggregation of NASA-TLX subscales. PRACTITIONER SUMMARY: NASA-TLX, a classical tool for mental workload assessment, is based on a weighted sum of ratings from six subscales. A new algorithm, which impacts on input data collection and computes weights and indexes from qualitative fuzzy integrals, is evaluated through laboratory and field studies. Pros and cons are discussed.

Association of physical job demands, smoking and alcohol abuse with subsequent premature mortality: a 9-year follow-up population-based study.

This study assessed the relationships of physical job demands (PJD), smoking, and alcohol abuse, with premature mortality before age 70 (PM-70) among the working or inactive population. The sample included 4,268 subjects aged 15 or more randomly selected in north-eastern France. They completed a mailed questionnaire (birth date, sex, weight, height, job, PJD, smoking habit, alcohol abuse (Deta questionnaire)) in 1996 and were followed for mortality until 2004 (9 yr). PJD score was defined by the cumulative number of the following high job demands at work: hammer, vibrating platform, pneumatic tools, other vibrating hand tools, screwdriver, handling objects, awkward posture, tasks at heights, machine tools, pace, working on a production line, standing about and walking. The data were analyzed using the Poisson regression model. Those with PM-70 were 126 (3.81 per 1,000 person-years). The leading causes of death were cancers (46.4% in men, 57.1% in women), cardiovascular diseases (20.2% and 11.9%), suicide (9.5% and 7.1%), respiratory diseases (6.0% and 4.8%), and digestive diseases (2.4% and 4.8%). PJD3, smoker, and alcohol abuse had adjusted risk ratios of 1.71 (95% CI 1.02-2.88), 1.76 (1.08-2.88), and 2.07 (1.31-3.26) respectively for all-cause mortality. Manual workers had a risk ratio of 1.84 (1.00-3.37) compared to the higher socio-economic classes. The men had a two-fold higher mortality rate than the women; this difference became non-significant when controlling for job, PJD, smoker and alcohol abuse. For cancer mortality the factors PJD3, smoker, and alcohol abuse had adjusted risk ratios of 2.00 (1.00-3.99), 2.34 (1.19-4.63), and 2.22 (1.17-4.20), respectively. Health promotion efforts should be directed at structural measures of task redesign and they should also concern lifestyle.

Relationships of physical job tasks and living conditions with occupational injuries in coal miners.

This study assessed the relationships of job tasks and living conditions with occupational injuries among coal miners. The sample included randomly selected 516 underground workers. They completed a standardized self-administred questionnaire. The data were analyzed via logistic regression method. The rate of injuries in the past two years was 29.8%. The job tasks with significant crude relative risks were: power hammer, vibrating hand tools, pneumatic tools, bent trunk, awkward work posture, heat, standing about and walking, job tasks for trunk and upper/lower limbs, pain caused by work, and muscular tiredness. Logistic model shows a strong relationship between the number of job tasks (JT) and injuries (adjusted ORs vs. JT 0-1: 2.21, 95%CI 1.27-3.86 for JT 2-6 and 3.82, 2.14-6.82 for JT>or=7), and significant ORs>or=1.71 for face work, not-good-health-status, and psychotropic drug use. Musculoskeletal disorders and certain personality traits were also significant in univariate analysis. Therefore job tasks and living conditions strongly increase the injuries, and occupational physicians could help workers to find remedial measures.

Effects of Manual Handling, Posture, and Whole Body Vibrations on Low-Back Pain.

To determine the effect of occupational stress on low-back pain (LBP), a cross-sectional study has been carried out, by interviews, on workers exposed to 3 stresses: manual handling (MH, 82 women and 264 men), whole body vibrations (WBV, 274 men), and static postures (278 women). Anthropometric data, occupational stress, LBP severity and frequency, and a psychological evaluation of these groups were compared to those of a control population of 208 workers (104 men and 104 women). The results show that 30% of the population had never suffered from LBP. Age and the body mass index of the workers were the parameters most closely associated with LBP. Women involved in MH had higher frequency and severity of LBP than their reference population. Men involved in MH or exposed to WBV had higher frequency of painful episodes than their reference population. Workers exposed to one of the stresses were on sick leave for LBP more often, and for longer periods, than workers in the reference group. The results show that individual factors are often decisive in the onset of LBP. Nevertheless, in the more serious LBP cases, occupational stress is an aggravating factor for LBP and its consequences.