(CNSNews.com) - A 10-year study of more than 105,000 American women that found no connection between abortion and breast cancer was criticized Monday by pro-life analysts who called it an example of "outcome-based science."
The survey - published in Monday's edition of the journal Archives of Internal Medicine - was conducted between 1993 and 2003 and found that neither an induced abortion nor miscarriage "was associated with the incidence of breast cancer."
The National Cancer Institute-funded study team was led by Karin Michels, associate professor in the Department of Epidemiology at the Harvard School of Public Health in Boston.
Researchers drew their information from the Nurses' Health Study II (NHSII), a project that began collecting data from female registered nurses in 1989 "to examine associations between lifestyle factors, reproductive factors and the occurrence of breast cancer and other major illnesses."
The survey followed 105,716 women between 29 and 46 years of age from 1993 on, with updates collected every two years until the study was concluded in 2003. In the end, it said, "16,118 participants (15 percent) reported a history of induced abortion, and 21,753 (21 percent) reported a history of spontaneous abortions [miscarriages]."
Over the 10-year period, 1,458 newly diagnosed cases of invasive breast cancer were reported. As a result of their analysis, the researchers found virtually no increase in the risk of getting breast cancer if a woman has had an abortion.
Concluding, the researchers noted that in 2003, "the National Cancer Institute convened an international expert panel to review and assess the existing evidence on reproductive events and the risk of breast cancer." The resulting report stated that "induced abortion is not associated with an increase in breast cancer risk."
"The data from the NHSII provide further evidence of a lack of an important overall association between induced or spontaneous abortions and the risk of breast cancer," they added.
As Cybercast News Service previously reported, pro-life analysts were skeptical of the findings of the 2003 conference, and neither were they persuaded by the study released on Monday.
Karen Malec, president of the Coalition on Abortion/Breast Cancer, told Cybercast News Service that she considered the new research to be "seriously flawed."
One of the problems with the study was its lack of sufficient follow-up time, Malec said. She noted that participants who reported having an abortion in the later part of the decade-long research period wouldn't have had time to get breast cancer.
"If you start smoking cigarettes today, are you going to develop lung cancer next month? Will you get it in six months?" she asked. "It's going to take years before you develop lung cancer, if you're going to get it at all.
"To do the study properly, they should have collected the abortion information only in 1993 and watched their study subjects for 10 years after that for breast cancer," Malec noted. "That would be the ideal way to do it."
Joel Brind, president of the Breast Cancer Prevention Institute, told Cybercast News Service that he agreed with Malec's point.
"The Nurses Health Study II is perfectly OK," he noted, but what the researchers did with that information made the new survey into "a very fine delicatessen that sells excellent salami. The problem is that the guy behind the counter puts his thumb on the balance, so you end up getting eight-tenths of a pound instead of a pound."
Brind pointed to another flaw in the study. "There are women who had induced abortions who also had spontaneous abortions, and it was important to adjust for that when they broke the data down" in one part of the research, Brind said.
"Why didn't they adjust their overall data for that variable as well?" Brind asked. "If they had - and they certainly should have - it would have shown a 12 percent increased risk [of abortion causing breast cancer]," he said.
Instead, they released the politically correct result - an example, he said, of "outcome-based science."
"This isn't the first time that Harvard Nurses Study researchers have produced the wrong epidemiological results," Brind said. In 1991, "they were wrong about combined hormone replacement therapy reducing the risk of heart attack and stroke, and now, they're wrong about abortion."
"Just because it's Harvard doesn't mean they're right," he added.
Proponents of a link between abortion and breast cancer risk say that upon conception, the level of estrogen in a woman's body increases dramatically. This results in the development of undifferentiated cells in the breast, which pose an additional cancer risk.
Late in the pregnancy, these cells become milk-producing cells, cease posing a greater cancer risk and in fact provide added protection against cancer.
If a woman has an abortion before that stage - and the vast majority of abortions would occur before then - her body is left with a high number of undifferentiated cells which increase the risk of her contracting breast cancer, they argue.
Where a woman suffers a miscarriage well into a pregnancy - in a motor accident, for example - she would face the same risk, the proponents say. However, when a spontaneous, early miscarriage occurs, the woman would not have had the surge in estrogen in the first place and therefore would not face the additional cancer risk.
"Even the National Cancer Institute agrees that increased childbearing, starting at an early age, protects women from breast cancer," said Malec. "Legislators have a moral obligation to require abortion providers to inform expectant mothers that if they have an abortion, their breast cancer risk will be higher than it would be if they have a baby.
"That's settled science," she added.
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