Introduction To identify workers facing particular challenges related to occupational exposure and health is valuable, as work environment plays an important role in terms of sickness absence (SA) and return to work. Assessing vulnerable occupational groups related to SA may facilitate decision makers in terms of allocating resources and interventions. The aim of this paper was to assess cause-specific SA rates by occupation and evaluate occupational specific excess fractions for SA.

Methods The source population was a Norwegian birth cohort (all 626 928 live-born individuals born between 1967 and 1976). Individual records on physician-diagnosed SA spells lasting >16 calendar days were obtained from the Norwegian event database FD-Trygd. The incidence rate of SA was estimated annually during 2005–2009. SA with musculoskeletal and mental diagnoses, was estimated for 31 occupational groups classified by ISCO-88 on a 2-digit level. Excess cause-specific SA was also estimated for each of the 31 occupations. All analyses were stratified by gender.

Result Workers in sales and service occupations and metal and machinery workers had the highest annual rates of musculoskeletal SA. Male metal and machinery workers had a 91% increased rate, compared to male corporate managers, while female workers in sales and services occupations had an 83% increased rate, compared to female corporate managers. For SA related to mental disorders, personal care workers had the highest rates among both men and women.

Discussion Occupation is an imprecise measure of work exposure and in the continued work on these data we will use a newly developed job exposure matrix to estimate the associations between specific physical and psychosocial exposures and cause-specific sickness absence by occupation.