Changes in confirmed plus borderline cases of congenital hypothyroidism in California as a function of environmental fallout from the Fukushima nuclear meltdown

Abstract

Radiation exposure has been linked to increased risk of congenital hypothyroidism (CH) for decades. CH is a relatively uncommon condition, occurring in about 1 of 2000 US births. Thyroid Stimulating Hormone (TSH) levels for each child born in California permitted an analysis of combined confirmed and borderline CH cases. Borderline/confirmed CH cases are more than seven times greater than just confirmed cases. Airborne levels of gross beta nuclear radiation in the US were elevated in the period starting several days after the Fukushima nuclear meltdown, especially in west coast states like California. The borderline/confirmed CH rate for newborns during the last 9.5 months in 2011 (exposed to Fukushima in utero) vs. births during other periods in 2011 and 2012 (not exposed) was significantly elevated, suggesting that adverse health effects to the newborn thyroid were not restricted to just a small number of confirmed CH cases. The sensitivity of the fetus to radiation exposure, plus the presence of thyroid-seeking radioiodine, suggest further analysis of Fukushima’s potential to cause adverse health effects in newborns is needed.