Introduction: Information on individual long-term work history is often required in occupational studies of diseases.
Content: The Supplementary Pension Fund Register has kept individual information on all employments, including start and end, on a company level backdating to 1964 for all wage earners in Denmark. Based on the computerised information, which also includes the unique personal identification number, it is possible to link information on employment history to information on individuals in nationwide registers of diseases.
Validity and coverage: Membership is compulsory and controlled by the Danish authorities, therefore information is considered to be accurate and complete.
Conclusion: This register is unique and of high value in occupational epidemiology.