Dec 3, 2012

Are 36% Thyroid Cysts in Tokyo Children a Good Comparison to Fukushima Thyroid Findings?

On December 1, 2012, the following article was published in Asahi Shimbun.  (Complete translation to follow after this article).

The headline states that 36% of children in Tokyo was found to have thyroid cysts.  Data mentioned is from 2,753 children who had thyroid ultrasound examinations done at a Tokyo thyroid clinic, Ito Hospital, from 2003 to August 2012.  The article concludes that this data, inclusive of data prior to the Fukushima nuclear accident, must mean thyroid ultrasound abnormalities in Fukushima children represent a normal incidence of such abnormalities.  

However, it is not clear how many of the 2,753 children were actually tested in the eight-year period from 2003 up to March 11, 2011, as opposed to the seventeen-month period from the accident up to August 2012.  As thyroid ultrasound examinations are rarely conducted in children under normal, non-radioactive circumstances, due to the rarity of thyroid disease in children, it is difficult to think the 2,753 can be evenly distributed from year to year as in 300 per year.  According to this article, Ito Hospital did not seem to specifically provide pre-accident findings.  Moreover, Ito Hospital is a facility authorized by the Japan Thyroid Association whose president, the infamous Shunichi Yamashita of Fukushima Medical University, sent the following letter to its members in January 2012.

Due to the lack of more detailed information such as the number of children examined in each year showing the change from year to year as well as the number of children actually examined up to March 2011, we can only speculate what the 36% might entail.

The newspaper article mentions that 189 children had multiple ultrasound examinations.  It seems likely that these 189 might belong to the pre-accident group, as anecdotal stories tell us most who got the ultrasound examination after the accident were told to follow up in one year.  

It is beyond our comprehension why this hospital would not provide more accurate data for comparison.  If they did provide it, why wouldn’t the newspaper cover it more accurately?    Does the data provide conclusive evidence of the impact of radiation from the Fukushima nuclear accident?


Complete translation of the newspaper article:

In relation to the many findings of cysts (fluid-filled sac) in thyroid examination of children in Fukushima Prefecture, a similar ratio of about 3,000 children was found to have cysts at a Tokyo hospital.  Dr. Kenji Iwaku at Ito Hospital in Tokyo reported it at the Japan Thyroid Association meeting on November 30.

Specialists say that “This data includes pre-accident data for comparison.  It is not likely that cysts found in Fukushima children are due to radiation exposure.”

According to the report, the data was the compilation of thyroid ultrasound results in 2,753 children under age 15 conducted at Ito Hospital from 2003 up to August 2012.  The result showed that 36% of the children had thyroid cysts.  

189 children had multiple ultrasound examinations: 42% saw an improvement with cysts getting smaller or resolving; 14% had cysts that became larger; and the remaining 44% saw no changes.  No children developed malignant disease such as cancer during the follow-up.

Because there was an increase in pediatric thyroid cancer after the Chernobyl nuclear accident in former USSR, Fukushima Prefecture has been conducting thyroid ultrasound examination in children under age 18.  Cysts were found in 35% of children tested last fiscal year and 42% this fiscal year so far.

The lack of comparative data in children in other areas has raised the voice that the cysts might be due to the effect of Fukushima Dai-ichi nuclear accident.

Shigenobu Nagataki, Nagasaki University emeritus professor in thyroid disease, said, “The data reported is from the study conducted using similar ultrasound equipments to what was used in Fukushima Prefecture.  It also includes data from pre-accident years.  Cysts in Fukushima children cannot be due to radiation.”

As the comparison to the Fukushima examination, the government plans on conducting thyroid ultrasound examinations outside Fukushima Prefecture, such as in Nagasaki Prefecture, for about 4,500 children.

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