Table 1

 Employment characteristics of 1101 cases and 1101 controls

*Some individuals were employed for two or more separate periods; hence the mean age at leaving is longer than the sum of the mean at start and mean duration of employment.
Age at start of employment (years)
Year of recruitment
Duration of employment (years)
    Range1 month–40 years1 month–40 years
Age on leaving* (years)