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.