Table 7

Rate ratios* and 95% CI by cumulative exposure to hydrocarbon lubricants for selected† cancer incidence among males from a Canadian petroleum company, 1969–94

Hydrocarbon lubricants (ppm-years)Malignant melanoma (ICD 9th revision 172)Bronchus & lung (ICD 9th revision 162.2–.5, 162.8–.9)‡Brain (malignant) (ICD 9th revision 191)Large intestine (except rectum) (ICD 9th revision 153, 159.0)All lymphopoietic cancers combined (ICD 9th revision 200.0–2; 200.8; 201; 202.0–1; 202.8–9; 203.0; 204–206; 207.0, 2, 8; 208)
*All models include terms for age, time since hire, and calendar period. Number (n) is number of cases in exposure category.
†Other malignancies evaluated but not shown due to less than 10 exposed cases includes kidney cancer (189.0–189.2), all leukaemias combined (204–206, 207.0, 207.2, 207.8, 208), Hodgkin’s disease (201), and non-Hodgkin’s lymphoma (200.0–2, 202.0, 202.8) (numbers in parentheses are ICD 9th revision codes).
‡Model includes additional term for smoking (ever v never/unknown).
§Exposure category combined with category above due to no or small number of cases. Rate ratio and confidence interval is based on observed counts in each cell combined. The counts shown in each cell are the original counts before combined categories.
Unexposed1.01.01.01.01.0
n = 13n = 21n = 6n = 15n = 33
>0–<0.02 ppm-years1.2 (0.4 to 3.0)1.2 (0.5 to 2.5)1.3 (0.3 to 5.1)1.1 (0.4 to 2.8)1.1 (0.6 to 2.1)
n = 6n = 9n = 3n = 6n = 15
⩾0.02–<0.20 ppm-years0.9 (0.4 to 2.2)0.8 (0.3 to 2.0)1.6 (0.4 to 6.4)1.3 (0.5 to 3.4)0.8 (0.4 to 1.7)
n = 6n = 5n = 3n = 6n = 9
⩾0.20 ppm-years§1.6 (0.7 to 3.6)2.5 (0.7 to 9.0)1.7 (0.7 to 4.5)0.4 (0.1 to 1.1)
n = 1n = 9n = 4n = 6n = 3