Thursday, 9 January 2014

BAD Science Debunked: Abortion Does NOT Cause Breast Cancer

Back in early December, when Babs Kay hitched her anti-feminism agenda again to yet another BAD (biased, agenda-driven) study purporting to link abortion and breast cancer again, DJ! took her on.

Joyce Arthur of Abortion Rights Coalition of Canada weighed in on the comments, promising a fuller analysis of the study.

Here it is. It is excellent.

The anti-choice movement has been making a lot of noise over a new study out of China, published in the journal Cancer Causes & Control, that purports to show a 44 percent increase in breast cancer risk for women who have had an abortion, with the risk increasing after each subsequent abortion. The study claims this may help explain the “alarming” rise in breast cancer in China over the past 20 years, which parallels the one-child policy introduced in 1979.
She proceeds to demolish its methodology, explaining the various kinds of known biases associated with this sort of study, including recall bias. Simply put, recall bias occurs when the two groups (the "cases," women who have or have had breast cancer, vs. the "controls", women who haven't) recall their medical histories differently. The "cases" are more likely to offer full details, while the "controls" may downplay their own abortion history. The problem is exacerbated by the level of abortion stigma associated in a culture.

She highlights this doozie.
Anti-choice activist Dr. Joel Brind has been promoting the ABC [abortion/breast cancer] association for over two decades. He claims that the Chinese study “neutralized” the recall bias argument. But Brind missed—or chose not to mention—that the journal article contained a confusing error, one that helped to hide the study’s own recall bias shortcomings. Early on, the study authors say:
The lack of a social stigma associated with induced abortion in China may limit the amount of underreporting.
But later in the study, the authors say:
[T]he self-reported number of IA [induced abortions] will probably be underestimated, as the stigma of abortion still exists in China, especially when a woman has more than two IAs. Therefore, this underestimation will inevitably create spurious associations between IA and breast cancer, especially for more IAs.
These two contradictory statements should never have gotten past the peer reviewers.
There are other fatal methodological flaws in the study and Joyce's article also links to other interesting work over the years and from several countries with widely differing abortion and breast cancer rates and attitudes towards abortion.

In short, many researchers have looked into the ABC link and it simply does not bear up under scrutiny.

As I've said many times before, this kind of bullshit needs to be called out every time it appears. It is unconscionable and irresponsible to appear to be using objective science to, as Joyce says, "to reinforce abortion stigma and frighten women."

And, of course, it's laughably hypocritical for fetus fetishists to wring their hands in pious concern for the well-being of women who have abortions when in other contexts, they delight in calling us "sluts" and "baby murderers".

So, while splendid analyses like this will change no anti minds, it should reassure women who have had or are contemplating having an abortion.



choice joyce said...

Thank you so much fern! :-) I've tweeted my article to Barbara Kay and Joel Brind, so we'll see what happens if anything.

There's also another new and even more ridiculously weak study out of India that the anti's are jumping all over:;year=2013;volume=50;issue=4;spage=316;epage=321;aulast=Bhadoria

It's another case-control study, so recall bias again. And all the associations found between cancer and other factors do not equal causation, which is not supported in this particular study for any association (even though a few of the factors have been previously established as causal). Perhaps most fatally of all for the ABC link, the Indian researchers did not even distinguish between induced abortion and miscarriage. Major FAIL for the anti-choice side.

fern hill said...

Joyce's link.

choice joyce said...

Now in a Twitter war with "Babs". It's just become apparent she hadn't bothered to even read my article before attacking it! Lol.

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