Tynes
T, Hannevik M, Andersen A, Vistnes AI, Haldorsen T
The
authors studied breast cancer incidence
in female radio and telegraph operators working on Norwegian
merchant ships. The women had potential exposure to
light at night, radio frequency radiation (405 kHz -25
MHz), and to some extent, extremely low frequency radiation
(50 Hz). The breast cancer incidence in the cohort of
2,619 women who worked between 1920 and 1980 was compared
with the Norwegian female population. Personal RF exposure
measurements were not available. Instead RF exposure
was estimated from job histories. Breast cancer risk
in the cohort was 1.5 times that of the general population.
In women over 50 years of age, there was a significant
trend for exposure to shift work, indicating exposure
to light at night and to electromagnetic fields. There
was a significant excess of uterine tumours (1.9 times
that of the general population) but not of other cancers,
although the numbers were low. Elwood in his review
considers that the "increased risks for both breast
and uterine cancer, with no excesses in leukaemia
or similar cancers, are more suggestive of a relationship
to reproductive or other lifestyle factors than to an
association
with RF emissions. An analysis adjusted for age at first
birth (a major risk factor for breast cancer), however,
still gave a risk factor of 1.5 for the association
between breast cancer and work as a radio operator."