Continued from Page One: Mr Carroll found that of seven reproductive risk factors known to be associated with breast cancer — such as later childbirth and hormone replacement therapy — the number of induced abortions in childless women was found to be the best predictor of breast cancer rates.
"Local variation within countries can be examined in addition to international comparisons," said Mr Carroll in his study.
"The south east of England has more breast cancer than other parts of the British Isles. It also has the highest abortion rate. Ireland has the lowest rate of breast cancer and the lowest abortion rate."
In four countries — England and Wales, Scotland, Finland and Denmark — a "social gradient" was discovered in which upper-class and professional women have more breast cancer than lower-class women, even though they were healthier in most other respects.
Mr Carroll suggests that common recourse to abortion in this class may explain the phenomenon.
His study has been welcomed by pro-life campaigners on both sides of the Atlantic.
Michaele Aston of Life said: "These findings highlight the need for further research into the breast cancer fink. All women have the right to know about the consequences of abortion. We hope the growing evidence of the link will encourage more researchers to invest time in properly analysing the evidence. The truth about a disease which affects the health of millions of women should not be ignored but investigated further."
Karen Malec, president of the US Coalition on Abortion/Breast Cancer, said: "It's time for scientists to admit publicly what they already acknowledge privately among themselves — that abortion raises breast cancer risk — and to stop conducting flawed research to protect the medical establishment from massive medical practice lawsuits."
A total of 29 of 41 studies published since 1957 provide evidence of a positive association, with a number claiming that women who aborted were 30 to 50 per cent more likely to develop the disease, In 2004 the studies were. reviewed, along with unpublished work, by a team from Oxford University which concluded that having an abortion does not heighten a woman's risk of suffering breast cancer.
Dr Lesley Walker, Cancer Research UK's director of cancer information, said: "Women should not be anxious about the suggested link between abortion and breast cancer. A number of large independent studies — including a recent reanalysis of data from 53 epidemiological studies — have found no evidence of a link."
Earlier studies, however, have argued that breast cancer is caused by high levels of oestradiol, the hormone that stimulates breast growth during pregnancy.
It is neutralised in women who take their pregnancy to full term but remains imbalanced in those who abort. This means that women at the highest risk of developing the disease are those who had an abortion without ever having given birth, had more than one abortion, or had an abortion when they had a family history of breast cancer.
Women who miscarry are not in danger because they possess natural ly low levels of the hormone. Changes to the cellular structure of the breasts of women who have already had children mean that the risk of them developing breast cancer is already reduced.
British medics who are convinced of a link include the newspaper columnist Dr Thomas Stuttaford, a former member of the Birth Control Campaign committee and the British Cancer Council.
There has been an 80 per cent increase in breast cancer incidence since 1971, the same period in which the annual numbers of abortions in Britain increased from about 18,000 to nearly 200,000.
It has been claimed that drinking a single glass of wine a day increases a woman's risk of getting breast cancer by six per cent.
Mary Kenny: Page 10