
Johnson and Johnson just lost another talcum powder cancer lawsuit ($72 million) - davidf18
https://consumerist.com/2016/02/24/jury-awards-72-million-in-johnson-johnson-talcum-powder-cancer-lawsuit/
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nkurz
The UK National Health Service has a recent overview of the study that was
used as evidence associating talc with ovarian cancer. They come to the
conclusion that while there is some evidence of an association, there is as
yet no firm evidence proving causation:
[http://www.nhs.uk/news/2016/03March/Pages/Talc-and-
ovarian-c...](http://www.nhs.uk/news/2016/03March/Pages/Talc-and-ovarian-
cancer-what-the-most-recent-evidence-shows.aspx)

That article helpfully links the paper itself, which is happily is available
to read in full:
[http://journals.lww.com/epidem/Citation/2016/05000/The_Assoc...](http://journals.lww.com/epidem/Citation/2016/05000/The_Association_Between_Talc_Use_and_Ovarian.6.aspx)

Glancing at it, it seems like a very professional writeup, with many
appropriate disclaimers about possible confounders. The key statistic that I
have not been able to find in the paper (although I presume it's in there
somewhere) is the incidence rate of ovarian cancer among the 1000 control
subjects. SEER says
([http://seer.cancer.gov/statfacts/html/ovary.html](http://seer.cancer.gov/statfacts/html/ovary.html))
that 1.3% of women will be diagnosed with ovary cancer during their lives.

Since the control subjects haven't lived their entire lives, and since
diagnosis is mostly in older women (age 63), I'd guess that they'd have only
something like fewer than 10 subjects on the control side with ovarian cancer.
I think this means that if by chance there happened to 2 or 3 more subjects
with cancer on the control side, the 1.3 increase in risk would be reversed,
and thus the evidence is extremely weak! Or am I wrong, and there is some way
of determining the odds ratio without knowing the true incidence rate among
the controls?

