Breastfeeding protects against cancer
Lack of breastfeeding major
contributor to Western breast cancer.
19 July 2002
HELEN PEARSON
 |
| For every year a woman
breastfeeds, her risk of breast cancer falls by more
than four percent. |
| © GettyImages |
|
|
Breastfeeding protects women from breast cancer, says a major
new study. But researchers are reluctant to advise women to
change their behaviour.
1 in 8 women in the United States will develop breast cancer;
1 in 9 in Britain. The new study suggests that, for every year a
woman breastfeeds, her risk of breast cancer falls by more than
4%. This is on top of the 7% reduction for each child she bears,
and regardless of other risk factors such as genes, smoking or
age of having her first child.
Some 5% of breast cancers in the Western world - that's
25,000 per year - could be prevented if women who had two or
three children breastfed each one for 6 months longer, the
researchers calculate1.
The results are "something else to factor in when trying to
decide whether to breastfeed", says team member Gillian Reeves
of the University of Oxford, UK. Telling women to change the
number of children they bear or the length of time they spend
breastfeeding is "unrealistic", she says.
Governments and workplaces could do more to encourage
breastfeeding, says cancer epidemiologist Tongzhang Zheng of
Yale University in New Haven, Connecticut. "It's not supported -
especially long-term breastfeeding," he says. In the United
States, half of women do not breastfeed at all, compared with a
quarter in Britain.
The researchers now hope to discover what happens in the
breast tissue during milk production that renders it more
resistant to disease. If they can develop drugs that mimic this
effect, it "may make big differences for a large number of
people", says Helene Hayman, who chairs Cancer Research UK the
charity that partly funded the study.
Bigger is better
An international research consortium called the Collaborative
Group on Hormonal Factors in Breast Cancer pooled the results of
47 published studies in 30 countries involving more than 50,000
women with breast cancer and nearly 100,000 without.
|
Governments and workplaces could do more to
encourage breast feeding
|
Tongzhang Zheng
Yale University |
|
|
Of the women in the study, those in developed countries such
as Britain and the United States had an average of two or three
children and typically breastfed each for 2 to 3 months. Those
in developing countries, where breast-cancer rates are four
times lower, had six or seven children and breastfed for around
2 years each.
"If women had the same number of children as those in
developing countries and breastfed for as long, breast cancer
would be a very rare disease," says lead researcher Valerie
Beral, also of the University of Oxford.
Breast-cancer incidence has begun to climb in developing
countries, coincident with a fall in family size and duration of
breastfeeding. In China, for example, restricting families to
one child has been accompanied by such a rise. |
