by Joel Brind, Ph.D.

A new systematic review and meta-analysis of abortion and breast cancer (ABC link) in China, was just published in November, 2013 in the prestigious, peer-reviewed international cancer journal, “Cancer Causes and Control”. It showed that the overall risk of developing breast cancer among women who had one or more induced abortions was significantly increased by 44%. In this meta-analysis (a study of studies in which results from many studies are pooled), Dr. Yubei Huang et al. combined all 36 studies that have been published through 2012 on the ABC link in China.

Also in peer-reviewed journals in 2013, Dr. Ramchandra Kamath et al. reported an odds ratio (a measure of relative risk) of 6.38 and Dr. A.S. Bhadoria et al. reported a relative risk of 5.03, i.e., a 5-fold—or 403%--increased risk of getting breast cancer among Indian women who have had any abortions. Not only are these relative risks much stronger than had been reported anywhere before (e.g., the 1.44 reported by Huang et al. in China and the 1.3 reported by my colleagues and I in our worldwide meta-analysis of 1996), but also in 2013, Dr. S. Jabeen and colleagues reported a relative risk of 20.62 among women in Bangladesh!

These new Asian studies change the game in ABC link research, and should completely abolish any credibility of the "politically correct" dictum of the US National Cancer Institute (NCI; a federal agency like the IRS and the NSA) that the ABC link is nonexistent.

Several reasons for this can be enumerated:

1. The Huang meta-analysis reproduces and validates our findings from 1996, even showing a slightly stronger link (1.44 v. 1.3, respectively), and on entirely different populations of women (Chinese women since 1988 v. worldwide women from 1957-1996, respectively).
2. The Huang meta-analysis also demonstrated what is called a "dose effect", i.e., two abortions increase the risk more than one abortion (76% risk increase with two or more abortions), and three abortions increase the risk even more (89% risk increase with three or more abortions). Risk factors that show such a clear dose effect have more credibility.
3. The new Asian studies—especially those from the subcontinent—put the final nail in the coffin of the main argument used to discredit the ABC link, variously called the "response bias" or "recall bias" or "reporting bias" argument. The argument goes like this. Due to social stigma that is attached to having an induced abortion, healthy women are more likely to deny prior abortions in their medical history study questionnaire than are women who've developed breast cancer. Hence, the argument goes, it would erroneously appear that abortion is more frequent among women who have had breast cancer.

Although no credible evidence for this response bias hypothesis has ever been presented (and plenty of good evidence against it) in ABC link research, the NCI and others have continually cited it as if it were a matter of fact, to deny the reality of the ABC link. The fact is that such response bias is only even plausible when the relative risk is relatively low, such as around 1.5. But such bias becomes extremely implausible when the relative risk is strong—e.g. 5 or 6 or more. Thus, while one might attempt to explain how some women with breast cancer might be more or less inclined to report their history of induced abortion, the numbers from India and Bangladesh are just too overwhelming: In the Jabeen study, 262 breast cancer patients were compared to 262 healthy (control) women. It was found that 231 of the patients (88%) had had any abortions, whereas only 70 out of the 262 healthy women (27%) had had any abortions!

It is important to note that the Jabeen data does raise the question as to why there should be such a strong link in Bangladesh, if abortion should have the same effect on women everywhere The answer is straightforward: In Bangladesh, breast cancer is still rare because a)early marriage and childbearing—the best known protection against breast cancer—is nearly universal; b) breastfeeding (also a protective factor against breast cancer) is also nearly universal, as is c) the lack of alcohol consumption (a known risk factor). Consequently, there's not much in Bangladesh besides abortion to cause breast cancer, so it really stands out.

It is really frightening when you start doing the math on the impact of abortion on a population of over a billion women—in India and China alone: Just a 2% lifetime risk of breast cancer due to abortion—a very conservative estimate—means upwards of 10 million women getting breast cancer, and millions dying from it. Welcome to the real war on women.

Joel Brind, Ph.D. is a Professor of Human Biology and Endocrinology at Baruch College, City University of New York; Co-founder of the Breast Cancer Prevention Institute, Somerville, NJ; and member of the Heartbeat International Medical Advisory Council.