4 ms·

Statistically significant, but slight (~25% increased risk, on average.) Still not great. Obviously, copper IUDs are an alternative for many, though they have

Statistically significant, but slight (~25% increased risk, on average.) Still not great. Obviously, copper IUDs are an alternative for many, though they have their downsides. One of the big uses of hormonal contraception is managing heavy periods, PMDD and other medical conditions. I had a friend who would throw up for days every time she was on her period. It went away pretty completely on birth control.

twawaaay 4y ago
The magnitude of risk increase in percentage has to be understood in context of baseline probability. 25% additional chance of getting hit by lightning and 25% additional chance of getting heart disease are two completely different results -- I don't mind the first but I would be scared by the second. About 13% of women develop breast cancer during their lifetime. 25% increase is then very significant, this is about additional 4% chance of getting cancer.
- jnwatson 4y ago
  Thank you for the context. The net increase in risk is what I was looking for.
- projectazorian 4y ago
  > About 13% of women develop breast cancer during their lifetime. 25% increase is then very significant, this is about additional 4% chance of getting cancer. The study didn’t measure lifetime risk, so your assertion is not correct. It measured risk of acquiring breast cancer before age 49. This is not the age when most women get breast cancer. Average age of onset for breast cancer in the US is 62.
  - twawaaay 4y ago
    While you are partly correct, the study just "didn't measure". It means the study does not say anything about getting cancer after 49. What it does not say is that there isn't any increase after the age women typically stop using contraceptives. In particular, since we don't know the mechanism in which contraceptives cause cancer, we can't say whether trend ends when women stop taking them or will increase their chance of getting cancer for the rest of their lives.
    - projectazorian 4y ago
      Yes, however, we have over a half century of data on hormonal contraception at this point, more than enough to measure the effect on lifetime risk. This very large meta-study showed the increased risk is no longer significant about ten years after stopping use: https://pubmed.ncbi.nlm.nih.gov/8656904/ https://pubmed.ncbi.nlm.nih.gov/8656904/ (btw, got that link from this article about the study in the OP, which points out potential confounders: https://www.statnews.com/2023/03/21/small-rise-breast-cancer-risk-hormonal-birth-control-study/ https://www.statnews.com/2023/03/21/small-rise-breast-cancer...)

twawaaay 4y ago

The magnitude of risk increase in percentage has to be understood in context of baseline probability. 25% additional chance of getting hit by lightning and 25% additional chance of getting heart disease are two completely different results -- I don't mind the first but I would be scared by the second. About 13% of women develop breast cancer during their lifetime. 25% increase is then very significant, this is about additional 4% chance of getting cancer.

jnwatson 4y ago
Thank you for the context. The net increase in risk is what I was looking for.
projectazorian 4y ago
> About 13% of women develop breast cancer during their lifetime. 25% increase is then very significant, this is about additional 4% chance of getting cancer. The study didn’t measure lifetime risk, so your assertion is not correct. It measured risk of acquiring breast cancer before age 49. This is not the age when most women get breast cancer. Average age of onset for breast cancer in the US is 62.
- twawaaay 4y ago
  While you are partly correct, the study just "didn't measure". It means the study does not say anything about getting cancer after 49. What it does not say is that there isn't any increase after the age women typically stop using contraceptives. In particular, since we don't know the mechanism in which contraceptives cause cancer, we can't say whether trend ends when women stop taking them or will increase their chance of getting cancer for the rest of their lives.
  - projectazorian 4y ago
    Yes, however, we have over a half century of data on hormonal contraception at this point, more than enough to measure the effect on lifetime risk. This very large meta-study showed the increased risk is no longer significant about ten years after stopping use: https://pubmed.ncbi.nlm.nih.gov/8656904/ https://pubmed.ncbi.nlm.nih.gov/8656904/ (btw, got that link from this article about the study in the OP, which points out potential confounders: https://www.statnews.com/2023/03/21/small-rise-breast-cancer-risk-hormonal-birth-control-study/ https://www.statnews.com/2023/03/21/small-rise-breast-cancer...)