[Cancer incidence among Icelandic female industrial workers.]

The aim of the present study was to investigate whether the cancer incidence pattern among unskilled female industrial workers in Iceland reflects a social divergence.

The design was that of a retrospective cohort study. The cohort comprised 13,934 women who contributed to a pension fund for industrial workers in Reykjavík during the period 1970-1997. The follow-up time was 1975-1997. The cancer cases were found by record linkage with the Cancer Registry, and the rates compared to those of the general female population with indirect standardisation. Standardised incidence ratios (SIRs) and 95% confidence intervals (95% CI) were calculated with and without 10 years lag-time, both for the cohort as a whole and after the study group had been restricted to those who had contributed to the pension fund any time after reaching 20 years of age.

RESULTS showed an excess of lung cancer, both when lag-time was applied and not applied, and before and after restriction had been made. SIRs for cervix cancer, and cancers of the colon, bladder, brain, connective tissue, and for cancers of the hema-topoietic system were moderately elevated. There was an excess of cancer of corpus uteri, especially when 10 years lag-time was applied, both in the whole group (SIR 1.67), and in the restricted cohort (SIR 1.69), and among those with a long employment-time (SIR 1.79). No deficit was seen for breast cancer, whereas this was found for ovary cancer.

The cancer pattern was in accordance with the results of other studies on women in this social category and indicates excessive smoking in the group. The excess of cancer of corpus uteri was unexpected. Because the group is burdened with various physical and chemical exposures at work, possible hazardous effects of these cannot be excluded.