A nationwide study involving more than 1.3 million children in Switzerland has concluded that there is no evidence of an increased risk of cancer for children born near nuclear power plants.
The Federal Office of Public Health (FOPH) and the Swiss Cancer League requested that the Institute of Social and Preventative Medicine (ISPM) at the University of Bern perform a study of the relationship between childhood cancer and nuclear power plants in Switzerland. ISPM then teamed with the Swiss Childhood Cancer Registry and the Swiss Paediatric Oncology Group to conduct the Childhood Cancer and Nuclear Power Plants in Switzerland (CANUPIS) study between September 2008 and December 2010. The results have now been published in the International Journal of Epidemiology.
The researchers computed person-years at risk for over 1.3 million children aged 0-15 years born in Switzerland between 1985 and 2009, based on the Swiss censuses 1990 and 2000. They also identified cancer cases in those children from the Swiss Childhood Cancer Registry. The ISPM then compared the rate of leukaemias and cancers in children born less than five kilometres, 5-10 km, and 10-15 km from the nearest nuclear power plants with the risk in children born further away.
Researchers concluded that the risk in the zone within 5 km of a nuclear power plant was “similar” to the risk in the control group areas over 15 km away, with 8 cases compared to 6.8 expected cases. In the 5-10 km zone there were 12 cases compared to 20.3 expected cases. And in the 10-15 km zone there were 31 cases compared to 28.3 expected cases. “A statistically significant increase or reduction in the risk of childhood cancer was not observed in any of the analyses,” said the ISPM.
The study concluded, “This nationwide cohort study, adjusting for confounders and using exact distances from residence at birth and diagnosis to the nearest nuclear power plants, found little evidence for an association between the risk of leukaemia or any childhood cancer and living near nuclear power plants.”
There are five nuclear power plants in Switzerland (Beznau I and II, Mühleberg, Gösgen and Leibstadt). About 1% of the population lives within 5 km of a plant and 10% live within 15 km.
The radioactive emissions in the vicinity of Swiss nuclear power plants are regularly monitored and the data are published by the Division for Radiation Protection of the FOPH. “The exposure due to emissions from nuclear power plants in the vicinity of these plants is below 0.01 millisieverts per year,” the University of Bern said. “This corresponds to less than 1/500 of the average total radiation residents in Switzerland are exposed to, mainly from radon gas, cosmic and terrestrial radiation and medical investigations and therapies.”
Claudia Kuehni, head of the Swiss Childhood Cancer Registry, commented: “Studies of atomic bomb survivors in Hiroshima and Nagasaki have shown that children are much more sensitive to radiation than adults. For this reason we focused on the place of residence at birth. This focus and the fact that we could include all children in Switzerland in a longitudinal study is a unique study feature of the CANUPIS approach.”
Previous studies on childhood cancer and nuclear power plants have produced conflicting results. For example, a case-control study from Germany published in December 2007 showed that the risk of leukaemia in small children living within 5 km of a plant was more than double that of children living further away, but did not link this to any effect of the power plants. Meanwhile, an extended in-depth study published in May 2011 by the independent Committee on Medical Aspects of Radiation in the Environment (COMARE) found no significant evidence of an increased risk of childhood leukaemia for children living close to the UK’s nuclear power plants.
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