Fukushima report sheds light on future health risks

By Helen Albert, Senior medwireNews Reporter

A detailed report carried out by the World Health Organization (WHO) estimates that the risk to the general public inside and outside Japan from the Fukushima nuclear accident is minimal with no anticipated increases in cancer rates.

However, for those living in the most contaminated areas (12-25 mSv effective doses for first year after incident), rates of several cancers are expected to increase significantly.

In these areas, the authors of the report predict that the rate of all solid cancers, breast cancer, and thyroid cancer will increase significantly above current rates in females exposed as infants, by 4%, 6%, and 70%, respectively. In males exposed as infants, leukemia is likely to increase by a significant 7% over current levels, they add.

In the second most contaminated area of the Fukushima prefecture (3-5 mSv effective doses for first year after incident), the WHO team estimates that increases in cancer risk are likely to be approximately one-quarter to one-third of those observed in the most contaminated areas.

"The primary concern identified in this report is related to specific cancer risks linked to particular locations and demographic factors," said Maria Neira, WHO Director for Public Health and Environment, in a press statement.

"A breakdown of data, based on age, gender and proximity to the nuclear plant, does show a higher cancer risk for those located in the most contaminated parts. Outside these parts - even in locations inside Fukushima Prefecture - no observable increases in cancer incidence are expected," she added.

The authors of the report note that levels of exposure were too low to affect fetal development or pregnancy outcome, and therefore state that no increases in spontaneous abortion, miscarriage, or congenital defects, among other adverse pregnancy outcomes commonly associated with radiation exposure, are expected to occur.

The WHO team also assessed the risks for nuclear power plant emergency workers and estimate that lifetime risks for leukemia, thyroid cancer, and all solid cancers are increased in this group. But, they note that more detailed estimates for this group are currently based on several possible exposure scenarios, and that "the collection and reconstruction of data regarding workers' dosimetry are ongoing processes," due to the very complex situation after the earthquake, tsunami, and nuclear accident.

"The WHO report underlines the need for long-term health monitoring of those who are at high risk, along with the provision of necessary medical follow-up and support services," said Neira.

"This will remain an important element in the public health response to the disaster for decades."

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