Breast feeding can significantly reduce the risk of breast cancer, according to a study by Cancer Research UK. The increase in the disease in developed countries is due to women having fewer children and breast feeding for shorter periods of time, the study says.The research is a detailed analysis of 47 published studies, with nearly 150 000 participants, from 30 countries.
Breast cancer is the most common cancer in the United Kingdom, with more than 39 000 cases a year. Nearly a third (12 700) are fatal. The research shows that the risk is reduced by 7% for each baby a woman has and that for every 12 months she breast feeds (not necessarily consecutively) she decreases the risk by a further 4.3%. Currently in the United Kingdom 69% of mothers start off breast feeding, but more than half have stopped after four months. The study says that if women breast feed each child for six months longer, 1000 cases of breast cancer a year could be prevented.
In Britain the risk of being affected by breast cancer by age 70 is currently 6.3 per 100 women. However, in developing countries it is 2.7 per 100 women. This difference is due to the differences in the number of children and the length of breast feeding. The researchers realise that returning to the pattern of childbearing that was typical a century ago is unrealistic. However, the research is a step towards the discovery of the mechanism by which breast cancer develops. Therefore, it could lead to developments in prevention and treatment of the disease.Lead researcher Professor Valerie Beral, of Cancer Research UK's epidemiology unit in Oxford, said, "The results of this study are a major step forward in our understanding of why breast cancer incidence is so high in developed countries. It's long been known that breast cancer is common in situations where women have few children and breast feed for short period.
We've shown that these factors alone account for much of the high rates of breast cancer in these settings."Sir Paul Nurse, interim chief executive of Cancer Research UK, added, "Each piece of evidence we uncover reinforces the view that hormonal and reproductive factors are vital to the development of breast cancer. Extending our knowledge of the disease is likely to bring about further advances in the clinic, as well as suggesting strategies for prevention."
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