A Danish study has revealed that the
organochlorine dieldrin may increase the risk of developing breast cancer.
In 1976, samples were taken from 7,712 women in Copenhagen,
Denmark. During 17 years of follow-up, 268 women developed invasive breast
cancer. Each woman with breast cancer was matched with two breast cancer free
women from the remaining cohort. In 1997/98, the scientists analysed a range of
organochlorines from the 240 women with breast cancer and the 477 controls.
Dieldrin was associated with a significantly increased
dose-related risk of breast cancer. Women with higher levels of dieldrin were
more than twice as likely to develop breast cancer.
The findings do not, however, suggest that exposure to DDT
and its breakdown product DDE have any influence on the risk of breast cancer.
The authors of the study are however recommending that all potential oestrogenic
pesticides, that mimic the female hormone oestrogen, should be more rigorously
screened for oestrogenic effects.
Pernile Hoyer, A, Grandjean, P, et al., Organochlorine exposure and risk of breast cancer, The Lancet, Vol. 352, 5 December 1998, p.1816-1820.
[This
article first appeared in Pesticides News No. 42,
December 1998, page 18]