Background To study associations between physical workload and health outcomes, valid and feasible exposure assessment methods are needed. Physical workload can be assessed by technical measurements, observations and questionnaires. Measurements and observations are often too costly in large epidemiological studies. Response rates to surveys are decreasing. Also, self-reported exposure is prone to bias since it may be influenced by e.g. health. Alternatives are to use job exposure matrices (JEM) where each job is attributed exposure measures. This enables large epidemiological studies to be conducted on registers and cohorts that include job titles. The aim was to construct a Swedish JEM for physical workload.
Methods Data from the Swedish Work Environment Surveys conducted every second year 1997–2013, including 90 077 working Swedes, were used. The JEM was based on eight questions concerning heavy lifting, strenuous work postures, repetitive work and physical strenuous work. The response scales specifiy the proportion of working time with the exposure. Occupational titles were coded on 4-digit level according to the 1996 version of the Swedish Standard Classification of Occupations.
Results The JEM provides information on physical exposures in 355 occupations, divided into men and women. Each occupation has been assigned mean values for specific exposures, e.g. heavy lifting, and overall physical exposure, as well as the proportion of workers exposed. Analyses will be presented on the predictive validity of JEM estimates on musculoskeletal disorders in a Swedish cohort.
Conclusions If the JEM is considered valid it will be a valuable tool in epidemiological studies of physical workload.