(4 categories): All jobs in the occupational histories were divided according to major ISCO88 groups (first digit), 1e3: high-skilled white-collar worker, 4e5: low-skilled white-collar worker, 6e7: high-skilled blue-collar worker and 8e9: low-skilled blue-collar worker.Participants were subsequently categorized according to occupational skill and
status based on the job category in which a participant had worked most years.