Human Heritable Effects Of Radiation

Last week I  had this long and difficult "discussion" with someone on YouTube who isn't accepting my claim that there have been no observable human heritable effects of radiation.  Since YouTube comments are limited to 500 characters, that platform doesn't help.

I thought I'd discuss here.

So let's dig in!



My claim is a parrot of BEIR VII, Chapter 4 which is a meta-analysis (top of pyramid is good):

"From the beginning of these efforts, it was obvious that in the absence of direct human data on radiation-induced germ cell mutations, quantitative estimates of genetic risk could be derived only through a knowledge of the prevalence of naturally occurring hereditary ill health in the population, the role of spontaneous mutations in supporting this burden, and plausible assumptions on the rates of induced germ cell mutations in humans." (emphasis mine)

Let's recall the evidence pyramid:

Direct human data is the key here.  We're not talking about effects on cells or tissues (bottom of pyramid) or effects on animals (second from pyramid bottom).

We're talking about cohort studies, near top of pyramid.  We're talking about comparing the offspring of an exposed cohort to the offspring of an unexposed control cohort.  The null hypothesis is that there is no statistical difference between the two, and we want to disprove the null hypothesis with the study at 90+% confidence (only a <10% chance we're statistically wrong).  We're looking for the manifestation of an excess of radiation-induced germ cell mutations in the offspring as congenital abnormalities, cancer, heart disease, Mendelian diseases, and others.

And when we do these sorts of studies, we find no significant excess of heritable effects.  We might do better if we did randomized, double blind studies but that requires intentionally exposing people to radiation, and is unethical.

We don't ignore the cell studies and animal studies, though.  Thanks to them we assume that heritable effects occur, but obviously the risk is very low (or we would statistically observe them in humans directly).  Chapter 4 goes on to describe how the risk is calculated in accordance with the paragraph I copied above.