Nuclear Radiation Risk Impacts One Group Far More Than Any Other

Young girls could be up to 10 times more vulnerable to nuclear radiation than other members of society, with girls aged up to five twice as likely to develop cancer as boys of the same age.

Understanding the risk posed by radiation exposure has been catapulted into public consciousness since February, when Russia invaded Ukraine. Talk of nuclear war has simmered ever since, with rhetoric ramping up on October 6 when President Joe Biden warned of "Armageddon," despite the U.S. having no new intelligence that Russian President Vladimir Putin was planning a nuclear strike.

"In Hiroshima and Nagasaki, many many people were vaporized immediately," biologist Mary Olson, founder of the Gender and Radiation Impact Project, told Newsweek, referring to the dropping of U.S. atomic bombs on the Japanese cities in 1945.

"But there were places where people did survive. Those are the people who are being studied now."

Data compiled from the long-term study of survivors of the Hiroshima and Nagasaki bombings are widely used by regulatory bodies and researchers across the world to assess the long-term impacts of radiation exposure on the human body.

Today, the U.S. Nuclear Regulatory Commission bases its evaluations of the impact of ionizing radiation on the public, and thus its decisions on nuclear licensing and regulation, on a subset of data which describes the "Reference Man."

The Reference Man, as defined by the International Commission on Radiological Protection, is 20 to 30 years old, weighs 154 pounds, is 5 foot and 6 inches tall, and is Caucasian with a Western European or North American lifestyle. This one-size-fits-all approach describes only a small subset of society.

In her research, Olson compared the effects of radiation on different demographic groups with the impact of this same level of radiation on the Reference Man.

"To me it seems natural to take those who were most impacted in that dataset and then compare it to where the regulatory agencies center their regulations," she said. The most severely impacted group in the dataset were young girls aged 0 to five at the time of exposure. "And what was the difference?," she said. "A factor of ten."

The second most impacted group were young males in that same age group. Even so, the young girls were twice as likely to develop cancer during the study period than their male counterparts. Across all age groups, women were more likely to develop cancer from radiation than men, although the sex difference became less marked in older age groups.

There is a clear explanation for why young people are more at risk of radiation: children's bodies are constantly growing which means their cells are dividing more quickly. As a result, their DNA is more vulnerable to tumor-inducing damage.

But why are young girls twice as vulnerable as young boys?

It is possible that the young girls in the study may have simply received more radiation than their male counterparts, but the consistency and significance of the correlation suggests that there is something else at play.

More research is needed, but Olson believes this discrepancy may be down to physiological differences in the male and female body. "Female bodies have a higher relative concentration of stem cells [than males]," she said. "These stem cells are much more sensitive to being hurt by the radiation."

While this is still a theory, it would explain the pattern seen in Olson's data: "The difference in stem cell concentration changes with puberty," Olson said. "The onset of menstruation results in a real tapering off of stem cells in the female body compared to the males." As we age, the concentration of stem cells in our bodies go down, and this decrease mirrors the near convergence of radiation risk for men and women in older age groups.

Assessing radiation risk with a one-size-fits-all approach is likely to open young women up to dangerous levels of radiation exposure, not just from nuclear warfare but also from more routine radiation exposures like CT scans, air travel and medical x-rays. As a result, the risk and harm of ionizing radiation on society is likely under-estimated.