Manual materials handling and related occupational hazards: a national survey in France
Introduction
Manual materials handling (MMH) is one of the recognized risk factors for back problems, with other factors such as bent and/or twisted position, whole-body vibration and vehicle driving (Riihimaki, 1991; Hagberg, 1992; Burdorf, 1997; Xu, 1997). Social and organizational factors at work play an additional role (Bongers et al., 1993). Evaluation of the burden of physical hazards and other work-related factors across industrial sectors and occupations is required in order to implement guidelines and ergonomic standards (Buckle, 1996; Dull et al., 1996). A better knowledge about high risk sectors is also needed for developing interventions at the workplace and setting priorities for prevention of occupational factors. Epidemiological evidence suggests that the high prevalence of back pain in some occupations is due to physical work load (Liira et al., 1996). Since most studies have focused on particular occupations or industries there are few surveys that present an overview of the occurrence of MMH across industry. They include surveys on self-reported working conditions (Second European Survey on Working Conditions, 1996; Conditions, organisation du travail et nouvelles technologies en 1991, Conditions, organisation du travail et nouvelles technologies en 1993), and surveys based on industrial facilities visits such as the National Occupational Exposure survey conducted in the US from 1981 to 1993 (Department of Health and Human Services). In the FINJEM job-exposure matrix developed in Finland (Kauppinen and Toikkanen, 1995) the list of agents comprises eight psychosocial stress factors, manual handling of loads, and nine other physiological stress factors. However, specific difficulties are met with a job-exposure matrix approach for postural load (Burdorf, 1996).
The data presented here come from a national survey in France aimed at assessing the frequency of various occupational hazards across industrial sectors and occupations (Heran-le Roy and Sandret, 1997).
The main aims of the present paper were to describe the proportion of workers involved in MMH in different occupations and industries, and the associations between MMH and other risk factors, with a special interest to physical and psychosocial factors at work considered as additional risk factors for musculoskeletal disorders.
Section snippets
The National Survey on occupational hazards
The study population comprised 48,190 active workers from SUMER 94 (Medical Surveillance of Occupational Hazards in 1994), a national survey from the French Ministry of Labour. The objective of SUMER 94 was to describe occupational hazards at the workplace in order to be able to define preventive strategies and research priorities in France. The study was the second one with the same objective, since a previous SUMER survey had taken place in 1987. The content was close to that of the national
Occurrence and duration of MMH across activities and occupations
The proportion of workers involved in MMH was 37.6%. Subjects exposed for less than 2 h per week accounted for 10.6% of the whole sample of 48,190 persons (i.e. 28.3% among exposed subjects), and 7.0% were exposed for more than 20 h a week (i.e. 18.6% among exposed subjects).
A description of the occurrence and duration of MMH according to branches of industry is given in Table 1. The highest occurrences of intensive MMH were observed in the manufacture of wood, paper, wood and paper products
Discussion
The study has several limitations: the definition of MMH was not very precise, and could be interpreted in a wide or restrictive way. The different dimensions of MMH such as lifting, pushing, pulling were not distinguished. MMH was only characterized by occurrence and duration, without additional information on frequency and magnitude. Assessment of duration of exposure was not based on observation; it is therefore subject to misclassification (Viikari-Juntura et al., 1996; Wiktorin et al., 1993
Conclusion
The data from the SUMER 94 survey give a description of the occurrence and burden of MMH across occupations and activities, and a better knowledge of occupational hazards related to MMH among blue-collar workers. The data emphasize work situations with cumulative occurrence of MMH and other risk factors of musculoskeletal disorders. These situations are observed both for physical hazards such as extreme positions or exposure to vibrations, and psychosocial hazards (dependency on colleagues and
Acknowledgements
The authors thank Timo Kauppinen and Laurence J. Fine for their help for comparative data. They thank Annie Schmaus for her help in the preparation of the figures, and Nadine Kaniewski for her secretarial assistance.
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