No Significant Difference
from Other Regions of Japan
In December 2011, there was a great piece by Michael Moyer, writing in a Scientific American blog, exposing the erroneous reasoning that was leading some anti-nuclear activists to claim that "the plume [from Fukushima] arrived on U.S. shores, spread everywhere, instantly, and started killing people immediately."
Today, an article appeared in The Mainichi in Japan showing that there is no significant gap between thyroid conditions in the Fukushima area and elsewhere in Japan. Most of us who follow nuclear issues closely have long realized that, just like the allegations about health effects on US shores, the logic of the claims about thyroid problems was faulty--the supposed effects were occurring too soon, and the radiation exposures weren't sufficient to cause such effects anyway.
The Mainichi article reports on a study comparing a population of young people in the Fukushima area with similar populations outside the Fukushima area and concluded that the percentages of small lumps and other anomalies detected in the surveyed population were "almost equal to or slightly lower in Fukushima."
The study was conducted by the Japanese Environment Ministry, which is the parent agency to the new Japanese Nuclear Regulation Authority. The Vice President of Fukushima Medical University, Shunichi Yamashita, noted that this survey demonstrates that "small cysts and lumps naturally exist in children when they are examined with the same precision level as in Fukushima."
One problem we sometimes face in modern times is that the precision with which we can measure things can exacerbate concerns. This has been true of radiation measurements themselves--very small increases over background can be measured, resulting in a level of anxiety that is disproportionate to the dose. We now see that it is also true of possible biological effects. The health industry has been discovering this phenomena in recent years with respect to a number of diseases. Now, it appears that we can add minor thyroid anomalies to that list.
The positive findings do not eliminate the need for continued follow up in the population that was exposed during the course of the accident. Although little or no effect may be expected, the circumstances mandate continued close monitoring. Such efforts should take a lesson from this recent study and should be sure to conduct comparisons with the population outside the affected area.