An ongoing study on the impact of radiation on Fukushima residents from the crippled atomic power plant has found 12 minors with confirmed thyroid cancer diagnoses, up from three in a report in February, with 15 other suspected cases, up from seven, researchers announced Wednesday.

The figures were taken from about 174,000 people aged 18 or younger whose initial thyroid screening results have been confirmed.

Researchers at Fukushima Medical University, which has been taking the leading role in the study, have said they do not believe the most recent cases are related to the nuclear crisis.