Low-back pain is a common symptom among workers, nearly everyone will be affected by low-back pain at some point in life. This opening line may sound deceptive since low-back pain is usually a self-limiting condition, where recovery without a physician's consultation can be demonstrated in the vast majority of all episodes. Yet, there is ample evidence that the symptom of back pain is recurrent, with one-year recurrence rates reported of more than 60%. In many industrial populations low-back pain is an important cause of sick leave and permanent work disability. This observation has certainly increased awareness of the low-back pain problem in industry. The considerable economic costs of low-back pain in the past decade has proved to be a main motive behind studies on occurrence and recurrence of low-back pain, causative factors in working conditions and methods of prevention. To institute primary prevention measures at the workplace risk factors in working conditions have to be identified from which workers should be protected. However, the efficacy of preventive solutions for low-back pain have not been described very often. The complex problem of characterization of exposure to risk factors will partly account for this situation. Risk factors are often simultaneously present, have complex interrelationships and vary considerably by subject and time. It is believed that research on measurement of risk factors in postural load on the back will contribute to better understanding and control of the occupational low-back pain problem. This belief runs through the studies described in this thesis like a continuous thread. This rationale is well-considered but- it must be admitted- retrospectively developed. Earlier research projects were focused on description of occurrence and nature of low-back pain in occupational groups. Based on vast experience in occupational hygiene, the attention in the research was soon drawn towards recognition and evaluation of causative factors in working conditions for the development of low-back pain among workers. A thorough review of epidemiologic literature revealed that techniques for measurement of exposure are still in their infancy. It must be concluded that the concept of exposure is hardly developed in epidemiologic studies on back disorders. As a consequence, dose-response and dose-effect relationships are barely available. Approaches of measurement strategies in occupational hygiene proved to be applicable to so-called ergonomic exposures. This thesis explores the possibilities and difficulties of the assessment of postural load on the back in several occupational situations. It will become clear that the problem of measurement of postural load on the back is complex and often not easily manageable; the challenge to develop valid and practical techniques tor assessing exposure to postural load is still open. Although ready-made solutions cannot be presented, this book will hopefully guide researchers in epidemiologic studies on occupational low-back pain towards better quantification and understanding of exposure to postural load. The reader may judge it this objective has been achieved. Since research is a life-time learning process comments and critical remarks will be warmly welcomed

back disorders, epidemiology
P.J. van der Maas (Paul) , C.J. Snijders (Chris)
Erasmus University Rotterdam
Erasmus MC: University Medical Center Rotterdam

Burdorf, A. (1992, December 2). Assessment of postural load on the back in occupational epidemiology. Erasmus University Rotterdam. Retrieved from http://hdl.handle.net/1765/40178