The Children of Fukushima: When Excessive Screening Creates Disease

March 30, 2016

By Greg Vachon, MD, MPH


Five years ago, a nuclear power plant in Fukushima, Japan, released deadly radiation into the environment. Survivors were of course worried about their future health, particularly their children’s. To answer these fears, the government decided to aggressively screen children for early thyroid cancer, a known effect of radioactive iodine.


Screening children for thyroid cancer after a massive nuclear accident like Fukushima makes a lot of sense, right? Testing exposed children early ought to provide a better chance for early detection and recovery. That’s what public health officials thought too. So, they tested as many children as possible. The results showed exactly what the public feared and officials predicted: Fukushima children had an alarming 30 times higher rate of early thyroid cancer than children elsewhere in Japan. There it was—proof that the Fukushima reactor accident caused thyroid cancer in children, right?


Wrong, actually. A follow-up analysis revealed that if the test were replicated elsewhere in Japan with the same methods, the 30-fold increase would disappear. The reason for the huge difference was that children outside of Fukushima simply were not screened. If they were screened, they too would have the same high rate. The Fukushima children who had concerning thyroids during screening underwent biopsies and thyroid removal, resulting in a lifetime of taking thyroid pills. Without the screening, the children would have been spared invasive medical procedures, and their parents would have been spared a lot of unnecessary worry. In this case, screening did not reveal dangerous disease. In fact, screening created disease.


The takeaway: careful what you screen for!


But how is a person to know whether a screening test is good or bad? Thankfully a smart, unbiased group of doctors and public health officials have already created a list of all the screening tests that make sense. You might be surprised by what was found to cause actual harm: PSAs (blog post here), artery scans of the neck, screens for lung disease. Despite tens of millions of thyroid tests, there isn’t clarity if they cause more harm than good. However, it is completely clear that they cost consumers and employers a lot of money. Bottom line: focus your screening efforts on the most beneficial A-rated tests. You’ll live longer (and happier!).

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