Evidence & Methods
Many biological, mechanical, and psychosocial factors are felt to impact low back pain.
In this repeated survey with a five-year gap, the authors found that frequent bending, driving industrial vehicles, working longer hours than expected, and poor support from supervisors were associated with low back pain.
While the study design does not allow for discussion of causation and there may well be undetected causative factors for low back pain that were not assessed, the findings are in line with several other studies in the field.
—The Editors
Low back pain (LBP) is a major public health problem. Although this condition can reveal specific and severe diseases, nonspecific LBP is much more frequent [1]. The annual prevalence of LBP is very high in Western countries; it was estimated to be 54% in men and 57% in women in the French general population from 30 to 59 years in 2002 [2]. Low back pain results in significant levels of individual pain and disability and is a frequent reason for seeking care [3], [4]. The working population is particularly affected by this condition, leading to work absenteeism, resulting loss of productivity and hence considerable socioeconomic costs for society [4], [5], [6], [7].
Many studies have been undertaken to identify risk factors for LBP in the last 20 years, and certain types of occupational biomechanical exposures have been causally linked (heavy load lifting, “whole-body” vibrations, bending and twisting, and so forth) [8], [9], [10], [11], [12], [13]. However, the respective role of each of them in the incidence of LBP is still a matter of debate. First, the definition of LBP is not homogeneous in the literature, and this sometimes gives rise to conflicting results [14], [15]. Second, the very high frequency of LBP in the general population and its recurrent evolution make the concept of incidence very difficult to apply or even unsuitable [16]. Third, most studies about risk factors for LBP are cross-sectional or case-control studies, which prevent any causal interpretation [12], [13]. Fourth, some studies have focused on specific occupational groups (nurses, automobile industry workers, bus drivers, and so forth), and their external validity is therefore insufficient for the generalizability of their conclusions [11], [12]. Fifth, the studies often assess a limited number of risk factors simultaneously, although LBP is known to be multifactorial. Last, certain factors that have been more recently highlighted and that might be worthy of interest such as psychosocial and individual factors are seldom integrated into the research, and their assessment raises methodological issues [17], [18], [19].
The current research on LBP focuses mainly on the prevention of transition from acute to chronic LBP or on the reduction of the consequences of chronic LBP because the latter is responsible for most of the costs associated with LBP [20], [21]. However, these goals are not easy to achieve, and reduction of the prevalence of LBP, whatever its duration and its characteristics, might be the best way to limit the human, medical, and socioeconomic costs involved.
From 2002, a network of occupational physicians in a French region (Pays de la Loire) has recruited a vast regional cohort of employees and conducted an extensive assessment of their occupational conditions. These workers have been the subject of a subsequent evaluation, concerning their health status in terms of potential musculoskeletal disorders, including LBP, about 5 years later [22].
The main objective was to assess the relative impact of biomechanical, organizational, psychosocial, and individual factors on the risk of later LBP in a cohort of male workers exposed to various levels of work constraints. The second objective was to compare the risk models of LBP in the workers with and without previous LBP.