A study on children in Fukushima Prefecture has found that nearly 36 per cent have abnormal growths on their thyroids. But doctors say there is no link between the cases and the disaster at the Fukushima Dai-ichi nuclear plant in March last year.
The Sixth Report of Fukushima Prefecture Health Management Survey, released in April, included examinations of 38,114 children.
Of them, 35.3 per cent - some 13,460 youngsters - had cysts or nodules of up to 5mm in their thyroids. A further 186 children had nodules larger than 5.1 mm.
A 2001 study by the Japan Thyroid Association found no children in the city of Nagasaki had nodules. Only 0.8 per cent had cysts on their thyroids.
'Yes, 35.8 per cent of children in the study have lumps or cysts, but this is not the same as cancer,' Naomi Takagi, an associate professor at Fukushima University Medical School Hospital, said.
'We do not know the cause of this, but it's hard to believe that is due to the effects of radiation,' Takagi added. 'This is an early test, and we will only see the effects of radiation exposure after four or five years.'