No, this is not about the Australian Broadcasting Corporation though possibly it will figure in the discussion at some stage because the ABC's views on controversial issues such as abortion are biased: commitment to pro-choice policies and no ABC staffer keen to present a pro-life perspective. However the ABC in the title of this Opinion piece relates to another controversy, the increased risk of breast cancer caused by induced abortion - this is known as the Abortion Breast Cancer (ABC) link.
A stunning new meta-analysis on the ABC link has just been published in a peer-reviewed cancer journal. Described as "Chinese Abortion-Breast Cancer bombshell" the meta-analysis of 36 Chinese studies from 14 provinces in China shows abortion increases breast cancer risk by 44%. This meta-analysis is particularly relevant to abortion legislation in Victoria where doctors are coerced, against their better scientific judgement, to refer women for abortions.
Dr. Joel Brind, Ph.D., professor of biology and endocrinology at Baruch College, City University of New York and cofounder of the Breast Cancer Prevention Institute, USA, reports that the new systematic review and meta-analysis of abortion and breast cancer in China, published in November in the prestigious, peer-reviewed international cancer journal, "Cancer Causes and Control," showed that the overall risk of developing breast cancer among women who had at least one induced abortion was significantly increased by 44%. In this meta-analysis (a review 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.
These results, said the authors, "were consistent with a previously published systematic review" referring to the 1996 review and meta-analysis that Dr. Brind compiled with colleagues from Penn State Medical Center, published in the British Medical Association's epidemiology journal. His study reported an overall significant 30% increased risk of breast cancer in worldwide studies. The new Chinese meta-analysis is a real game changer, not only does it validate the earlier findings from 1996, its findings are even stronger, i.e. shows a 44% increased risk versus the 30% increased risk in Dr. Brind's meta-analysis of 1996.
Dr. Brind comments: "Noteworthy is that the Huang study follows right on the heels of two new studies this year from India and Bangladesh, studies which reported breast cancer risk increases of unprecedented magnitude: over 600% and over 2,000%, respectively, among women who had any induced abortions."
Huang's meta-analysis also shows 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 dose effect have more credibility. Although previous studies of the ABC link were a bit more heterogeneous and the dose effect less clear, it has been shown that the risk increase is greater the longer the pregnancy continues before abortion. Hence, an 18-week abortion increases the risk more than a 12-week abortion, and a 12-week abortion increases the risk more than an 8-week abortion.
In this new meta-analysis Huang et al. put to rest 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 abortion, healthy women are more likely to deny prior abortions in their medical history questionnaire than are women who've developed breast cancer. Hence, the argument goes, it would erroneously appear that breast cancer is more frequent among women who've had an abortion. (Feminists gullibly accept the argument that women routinely lie on medical questionnaires!)
Huang et al. dispatch this canard. They explain, "The lack of a social stigma associated with abortion in China may limit the amount of underreporting and present a more accurate picture of this (abortion-breast cancer) association."
Huang et al. then proceed to explain why two earlier high-profile studies in Shanghai did not find the link. They do so essentially by citing and pursuing the argument Dr. Brind articulated in the "British Journal of Cancer" in 2004, and more importantly, proving the point by performing a "meta-regression" of all the Chinese data.
In Dr. Brind's 2004 published letter, he explained that the Shanghai population was unsuitable for studying the ABC link in the usual manner, because the prevalence of abortion was too high in the general population.
In essence, the value of epidemiology is to identify exposures-like abortion-which may increase the risk of a given disease-like breast cancer-by comparing those exposed to the typical, unexposed population.
But when the prevalence of the exposure becomes the rule rather than the exception-as in the Shanghai studies where the majority of women had had at least one abortion-the unexposed women are not typical.