19th March 09:59
Article : Heart disease, breast cancer and estrogen
Researchers are looking at how levels of estrogen produced by women in
different societies might affect their risk of breast cancer and heart
In the UK, breast cancer affects around one woman in nine - a far higher
rate than in many other countries, especially those in the developing world.
Heart disease claims 20 per cent of all lives in the UK, but is far less
common among pre-menopausal women than among men. The link, in both
patterns, is the female hormone estrogen. Research has shown that estrogen
promotes breast cancer, but protects against heart disease.
Dr Tessa Pollard of the University of Durham, England, believes that British
women today are producing much more estrogen than they did in the past.
Research with women in Mali and the Congo, whose lifestyles are probably
closer to those of our ancestors, show they have far fewer menstrual periods
in a lifetime than does a woman in an industrialized society (about 100
compared to 400). This is linked to differences in the number of pregnancies
and the duration of breastfeeding and means that a modern Western woman is
exposed to estrogen for a longer time throughout her life, raising the risk
of breast cancer.
Western women's ovaries also produce more estrogen. Dr Pollard suggests this
is associated with higher calorie intake and less physical activity in
modern societies. Her current research is also looking at whether levels of
nutrition pre-birth and in early childhood set the ovarian production of
estrogen for the rest of a woman's life. She is looking at estrogen
production in both women born and bred in the UK, comparing it with migrant
women born in South Asia. It's hoped that this work will lead to ways of
pinpointing women most at risk of breast cancer because of their levels of
estrogen production and lifetime exposure to the hormone.
British Association for the Advancement of Science Meeting 9th September