Table 1

Vital status, demographic, and employment characteristics of employees from a Canadian petroleum company, by gender

CharacteristicsTotal cohort
*As of end of follow up (31 December 1994).
†Seven males who died before 1 January 1969 (date tumour registry ascertainment began) were excluded from cancer incidence analysis cohort. Additionally, six males and two females who had a death certificate indicating a malignant neoplasm death but who were not identified by the tumour registry as incident cancers were included as tumour cases.
Alive (% of total)*16768 (97.3)7953 (98.6)
Deceased (% of total)*462 (2.7)109 (1.4)
No. of persons with one or more incident tumours identified*†325 (1.9%)184 (2.3%)
Average year of entry into follow up1978.81978.9
Average age at entry into follow up29.127.5
Average year of hire1977.51977.8
Average duration of employment (years)8.86.4
Average follow up time (since hire in years)16.816.7
Total person-years268290125522