Sickness absence as a risk marker of future disability pension: the 10-town study.

METHODS Participants selected from the on-going Finnish 10-town study comprised all 46 569 full time municipal employees who had a job contract lasting a minimum of three full consecutive years between 1 January 1990 and 31 December 2000, and were below 55 at the end of the follow up, the age before which medical causes exclusively determine granting of disability pension for municipal employees in Finland. We obtained sickness absence records from employers’ registers for a fixed three year period of employment (the length of exposure assessment period was the same for all participants). The start of this period varied between 1 January 1990 and 1 January 1998 depending on the date when the job contract began. For those employees who had a job contract of more than three years, absences for the first three years were included in the analysis. We determined disability retirements from the end of the assessment period for sickness absence until the end of 2001 (mean follow up 5.1 years) using data obtained from the Finnish Local Government Pensions Institution and the State Treasury—that is, institutions granting all the pensions to Finnish public sector employees. We analysed all cause disability pensions and pensions attributable to psychiatric diseases (International Classification of Diseases, ICD9 290– 319; ICD10 F00-F99) and musculoskeletal diseases (ICD9 710–739; ICD10 M00-M99). Death certificates used to determine the end of follow up for participants who died