Design factors in epidemiologic cohort studies of work‐related low back injury or pain

Abstract

The connection between work‐related exposures and the onset of back injury or pain is complex and not clearly understood. This paper raises design issues related to the planning and conduct of cohort studies of industrial low back pain (or injury)(LBP), with care given to definition and measurement of exposure and outcome events. These issues include sample size, outcome definition, study biases, and practical considerations when seeking and maintaining company collaboration with a research effort. Without resolving these issues, the authors conclude: (1) cohort studies of worksite‐based LBP are needed to elucidate the causal associations between work tasks and LBP onset, (2) both acute and cumulative exposures should be assessed as risk factors for low back injury or pain, and (3) attention should be paid to the planning of such studies and minimization of potential biases that can limit the validity of the results. These design issues will benefit researchers and companies engaged in the planning and conduct of cohort studies of industrial LBP. Am. J. Ind. Med. 32:153–163, 1997. © 1997 Wiley‐Liss Inc.

Work factors as predictors of intense or disabling low back pain; a prospective study of nurses’ aides

“…It is not likely, though, that selection bias due to withdrawal between baseline and the follow ups explains the main findings in this study. A healthy worker selection, 21 due to the fact that unhealthy persons have avoided specific high exposure jobs or changed to lower exposure jobs prior to the data collection, may cause interpretation problems in studies of occupational populations. The result may be an underestimation of associations between work factors or high exposure categories of work factors and health related outcomes.…”

Lower Back Problems and Work-Related Risks in a South African Manganese Factory

“…Studies of worksite-based LBP are thus needed to explicate the association between work tasks and the onset of LBP [26], and how exposure to certain work factors might predispose the risk of developing LBP. Although cross-sectional studies cannot answer all of the posed questions and problems, it does increase the understanding of this complex phenomenon, particularly in unexplored populations at risk.…”

How reliable and valid is the coding of the variables of the European Statistics on Accidents at Work (ESAW)? A need to improve preventive public policies

“…For this reason we assured the homogeneity of the personal characteristics, educational background and professional experience of the experts and, in an attempt to further minimize this bias, we followed the recommendations of various authors (Kraus et al, 1997;Mittleman et al, 1997;Veazie et al, 1994;Krippendorf, 2006;Cummings et al, 1995;Burdorf et al, 1997), and developed a detailed protocol for the collection of information and documentation in a homogeneous manner and carried out a workshop for building up practice and establishing common criteria when analysing an accident, in order to obtain a maximum definition and harmonization between the different cases and variables. There may be a recall bias associated to the fact that the visit and assessment of the expert took place an average three months after the accident -although in all cases it was less than the 6 months maximum recommended in some studies (Veazie et al, 1994).…”

“…Following the instructions of some authors (Kraus et al, 1997;Mittleman et al, 1997;Veazie et al, 1994), and to further ensure the high quality of the data collected, a working template was specially designed to facilitate data gathering to the experts, which included the variables to collect, a conceptual description and potential categories of response (see supplementary material). Subsequently, Catalan Labour Authority experts received training for 15 h, aimed to explain the procedure, standardize the criteria for data collection and undertake practical coding exercises on the ESAW coding system using as an example 8 real accidents previously investigated by the experts themselves.…”