You may have a leg to stand on if these were small groups being studied. Those underlying studies have ns of between 5000-100,000 with significant concurrency in results. You can’t just hand wave that away.
It is _not_ the tobacco story all over again, because the health effect of long-term tobacco use "as directed," and as occurs normally in real-life, results in an extremely massive increase in the risk of death from lung cancer, with a staggering 1 out of 4 long-term smokers (using more than 5 cigarettes a day) dying of lung cancer - something like a 5000% increase.
The health linkage between regular tobbaco use and negative health outcomes is overwhelming.
It is not the same thing here. These are small effects and difficult to notice, and there could be other confounding factors. (Maybe people in environments with lots of PFAS chemicals are exposed to other chemicals common in polluted water sources).
"A doubling of perfluorooctane sulfonate (PFOS) in maternal serum was associated with a 39% (p < 0.001) reduction in diphtheria antibody concentration in children (age 5 yr), with increased odds of falling below clinically protective values against diphtheria and tetanus at age 7 yr."
> A study of heavily exposed workers (n = 462, geometric mean serum PFOA of 4048 ng/mL) detected significantly increased incident mortality for cirrhosis (relative risk = 3.87, 95% CI 1.18–12.7) and liver cancer (relative risk = 6.69, 95% CI 1.71–26.2)
These are NOT small effects. These are strong p-values with large hazard ratios over and over again throughout the entire review.
I have no domain knowledge here but those CIs are quite large and both get close to 1 at the lower edge.
Yes, it shows that with 5% probability the risk is only 1.18 - why choose to focus on those 5%? According to the study there is an equal chance that the relative risk is 12.7 times normal, why should we ignore that?
Your reading of the CIs is off. It isn't telling you that there's a 5% chance that the real risk is 1.18. It's saying there's a 5% chance the real risk doesn't lie in the CI, and could be anywhere outside the CI, including 1 (no effect).
Here's the main point. Increase the significance level slightly, say to 97% (if this is a 95% CI, or 92% if this is a 90%, etc). Then a CI that large and that close to 1 at the left edge will turn into a CI that includes 1. The effect is not significant at all at that level. It wouldn't be saying the true effect is significant with some probability or whatever you seemed to be interpreting CIs to say. It would be saying there's no effect.
This is markedly different from the case of cigarettes, where the p-values are astronomically small. Since earlier comments seem to compare these chemical to cigarettes.
But again, I haven’t read the paper! Just chiming in with some half-forgotten epidemiology. :-)
Those are a very small part of the affected ones, probably firefighters or 3M production workers. Remember that the dosage makes the poison.
Or are you going to argue about how antibodies work?
Again, the headline figure you're quoting sounds alarming, but if it's accurate and applicable to the broader population, then we should be seeing that effect outside the lab as well.
Should we wait for that to happen if the risk is obvious?
There's loads of things I use in every day life that I wouldn't want to ingest in odd quantities. I handle gasoline and paint thinner and dishwashing detergents and hand soap every now and then but if you tried to get me to even drink a teaspoon of it I'd probably turn you down. Is the rule now if you wouldn't drink a glass of it you should never handle it in any way?
By the way, please do not drink that 26% salt brine. It will do very terrible things to your body and probably significantly hurt you.
> Is the rule now if you wouldn't drink a glass of it you should never handle it in any way?
Some things are not safe at any level. Lead (Pb) for example. So what about PFAS? Does it accumulate in the body? What are the effects of long-term ingestion?
My question was intended to see just how serious people were, who were making the argument that PFAS weren't a thing to be concerned about.
I'd avoid drinking a glass of motor oil as well, but I still prefer having my car lubricated at the end of the day.
feel free to develop a formula, if you so desire