It is astonishing to me how so many can make so many comments and claims re: studies they have obviously never read. So abortion rights advocates laud the Beral meta-analysis which reported no link (even though they excluded studies on the basis of such unscientific reasons like "principal investigators... could not be traced". It must be tough to locate the authors of a study published in 1957!),and they trash the meta-analysis of Huang et al., who agreed with our own 1996 meta-analysis that did find a link. (and by the way, for the commenter who was worried about studies being peer-reviewed and published, our 1996 meta-analysis --published in the British Medical Associations's Journal of Epidemiology and Community Health--and that of Huang this year had in common that we included all peer-reviewed, published studies, whereas the majority of studies included by Beral had not been published at all!

And of course, the Beral meta-analysis was published 10 years ago. Since 2007, in addition to the Huang meta-analysis, there have been published in peer-reviewed medical journals, at least 17 studies from the rest of Asia; 12 from the Indian subcontinent. All of them report increased risk (Preponderance, anyone?) As I point out in my article, these are populations in which the effect of abortion stands out prominently precisely because there are few other common risk factors for breast cancer. One of you said that Huang showed that the "best" studies showed no link. Incorrect: the worst studies, i.e., those from Shanghai, where the majority of women have had at least one abortion. As Huang pointed out in his meta-regression analysis (within the meta-analysis, for anyone who actually cares to read it), the evidence of the link disappears when the prevalence of abortion is too high, because there is no population of typical women who have not had an abortion. So, sure, you can do a study that finds no link whenever you want to; just do it in other place where abortion is at least 60% prevalent among the women, and voila! you find no risk increase, except it won't be valid.

Now to answer those who wondered about spontaneous abortions: No, everyone in the field agrees that they generally do not contribute to breast cancer risk. The reason is that they are not the same hormonal interruption as induced abortion. Rather, they are naturally terminated pregnancies (most in the first trimester) that failed in the first place for lack of the usual hormonal surge (which causes a growth spurt in the breasts). No hormonal surge; no growth spurt; no increased cancer risk. On the other hand, the same hormonal blow as a late term abortion happens even in live births that occur before 32 weeks. So very premature birth (before 32 weeks) doubles breast cancer risk, while a delivery after 32 weeks reduces risk.

Finally, suseonline, I quite agree that neither your nor my religious beliefs should impact our scientific judgement. But two can play the sarcasm game:-)

Prof. Brind do you have publicly accessable links to Huang's paper and some of the others you refer to?

It is a difficult space, so many on both sides of the broader debate on abortion show a distinct lack of interest in truth. Also to help the process for those trying to get a better understanding of the claimed link any rebuttals of those findings?

I'm on the pro-choice side of the debate but don't have the level of emotional investment in that precludes a willingness to consider evidence that does not sit well.

As George pointed out a link to an increased risk does not require outlawing an activity, although I do suspect the real issue would be legal liability. There would seem to be plenty of scope for law suits against the government in the future if funding is provided for abortions while a claimed link to cancer exists.

If you wonder about the level of scepticism from my perspective so many on the anti-choice side of the debate cry wolf so often that no claims from those opposed to abortion can be taken at face value.

Do you have any comments on the issue with recall in these studies that Killarney mentioned (I will leave aside her comments on DV, a lot of history there)? Thats a topic I've seen elsewhere in regard to this topic.

R0bert

Well, George I am not really that concerned about Joel Brind’s religion.

What I am concerned about is the fact that Joel Brind has disregarded the largest meta-analysis on the topic covering 83,000 individuals from around the world in favour of a seriously compromised meta-analysis from China.

The fact that he has chosen to prove the biological connection between having an abortion and contracting breast cancer later in life, thereby dissuading countless women from killing their unborn children, rather than assess what the data shows means that he is too biased to be reliable.

Agronomist,

That is a different cup of tea. As I said, I am not a specialist on these matters, maybe you are. But even so, you cannot expect to resolve the problem of whether or not Bird’s research methods are fair - involving a serious accusation concerning falsification and his integrity as a university professor - on this forum, where - I presume - the majority of us are also non-specialists and can have only a non-critical understanding of what he is saying.

Joel Brind's explanation around spontaneous abortions is very obviously wrong. Spontaneous abortions occur for a whole host of reasons, not because of a lack of hormonal surge.