An expert-based job exposure matrix for large scale epidemiologic studies of primary hip and knee osteoarthritis: The Lower Body JEM

Abstract

BackgroundWhen conducting large scale epidemiologic studies, it is a challenge to obtain quantitative exposure estimates, which do not rely on self-report where estimates may be influenced by symptoms and knowledge of disease status. In this study we developed a job exposure matrix (JEM) for use in population studies of the work-relatedness of hip and knee osteoarthritis.MethodsBased on all 2227 occupational titles in the Danish version of the International Standard Classification of Occupations (D-ISCO 88), we constructed 121 job groups comprising occupational titles with expected homogeneous exposure patterns in addition to a minimally exposed job group, which was not included in the JEM. The job groups were allocated the mean value of five experts’ ratings of daily duration (hours/day) of standing/walking, kneeling/squatting, and whole-body vibration as well as total load lifted (kg/day), and frequency of lifting loads weighing ≥20 kg (times/day). Weighted kappa statistics were used to evaluate inter-rater agreement on rankings of the job groups for four of these exposures (whole-body vibration could not be evaluated due to few exposed job groups). Two external experts checked the face validity of the rankings of the mean values.ResultsA JEM was constructed and English ISCO codes were provided where possible. The experts’ ratings showed fair to moderate agreement with respect to rankings of the job groups (mean weighted kappa values between 0.36 and 0.49). The external experts agreed on 586 of the 605 rankings.ConclusionThe Lower Body JEM based on experts’ ratings was established. Experts agreed on rankings of the job groups, and rankings based on mean values were in accordance with the opinion of external experts.

Varicose veins in the lower extremities in relation to occupational mechanical exposures: a longitudinal study

“…Individual estimates of exposures to the lower extremities were obtained by connecting the occupational title with the newly developed Lower Body Job Exposure Matrix (JEM) 32. The JEM cross-tabulates 121 job groups with expected similar exposure patterns, and five experts’ ratings of number of hours per day spent standing/walking and total load lifted per day (kg).…”

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension: prospective cohort study

“…During recent years, several JEM have been constructed to capture exposure to physical working conditions (14,16). However, only few studies have used mechanical exposure JEM, and most of these assess mechanical exposure in relation to development and consequence of different diseases or pain symptoms (14,(17)(18)(19)(20)(21)(22).…”

“…The use of an expert-based job exposure matrix (JEM) may provide an appropriate alternative to selfreported data when investigating the relation between mechanical exposures through working life and health related labor market outcomes (14,15). During recent years, several JEM have been constructed to capture exposure to physical working conditions (14,16).…”

“…Occupational mechanical Sundstrup et al exposures throughout working life were assessed with data from a JEM -the lower-body JEM (10) -that was originally developed for large-scale epidemiological studies of primary hip and knee osteoarthritis (14). The JEM is based on expert judgments of mechanical exposures in 121 homogeneous exposure groups and provide estimates of total load lifted per day and daily frequency of lifting loads weighing 20 kg, as well as hours of exposure to standing/walking, sitting, kneeling/squatting, and whole-body vibration during an 8-hour working day (14,17).…”

“…Occupational mechanical Sundstrup et al exposures throughout working life were assessed with data from a JEM -the lower-body JEM (10) -that was originally developed for large-scale epidemiological studies of primary hip and knee osteoarthritis (14). The JEM is based on expert judgments of mechanical exposures in 121 homogeneous exposure groups and provide estimates of total load lifted per day and daily frequency of lifting loads weighing 20 kg, as well as hours of exposure to standing/walking, sitting, kneeling/squatting, and whole-body vibration during an 8-hour working day (14,17). The CAMB questionnaire used for the present study provided information about job history (ie, job titles and length of service for the five longest-held occupations) for each individual in the study population (18,19) and covered in average a total period of 30.6 years per individual worker (31.5 in men and 29.7 in women) (18).…”