Did Fukushima cause babies on the US West Coast to be more at risk from hypothyroidism?

Question

A recent paper entitled Elevated airborne beta levels in Pacific/West Coast US States and trends in hypothyroidism among newborns after the Fukushima nuclear meltdown has been published and the abstract says:

The number of congenital hypothyroid cases in these five states from March 17-December 31, 2011 was 16% greater than for the same period in 2010, compared to a 3% decline in 36 other US States (p < 0.03). The greatest divergence in these two groups (+28%) occurred in the period March 17-June 30 (p < 0.04).

This study is the basis for claims in the media such as:

Researchers have discovered that the Fukushima nuclear disaster has had far-reaching health effects more drastic than previously thought: young children born on the US West Coast are 28 percent more likely to develop congenital hyperthyroidism. [Emphasis mine]

I could argue that the authors have form for dodgy data and the publisher is of low quality, and that it doesn't pass my sniff test, namely that if there was such an effect in the US, we'd surely be seeing a massive amount of abnormalities in Tohoku and Tokyo, but I'd like to get an answer more grounded in facts.

Answer 1

There is no clear evidence that this is the case.

From the report itself:

The data presented in this paper, including both exposure levels and CH incidence, should be considered as preliminary. They require confirmation and expansion, including long-term follow-up of infants and other children.

Understanding why CH rates have risen in developed nations such as the US is a complex task, as multiple factors are likely involved. Exposure to radiation, especially the thyroid-seeking radioiodine isotopes, should be considered as one of these factors. The meltdown at Fukushima Dai-ichi presents an opportunity to analyze this factor, and studies such as this one should continue.

The authors themselves don't believe that this report is conclusive.

These authors have a tendency to report "preliminary findings" with misleading titles. a quote from another publication: Because a large number of deaths are involved (37 and 125 in the two periods), the change approaches statistical significance at p<.09 (p<.05 is significant).