"Nuclear plants 'do not raise child cancer risk'" says BBC News – a headline which addresses a controversy that has been around since the 1980s. The headlines are based on a study looking at more than 20,000 children in Great Britain...
“Nuclear plants 'do not raise child cancer risk',” says BBC News – a headline which addresses a controversy that has been around since the 1980s.
The headlines are based on a study looking at more than 20,000 children in Great Britain who developed childhood leukaemia or non-Hodgkin lymphoma before the age of 15, between 1962 and 2007. It compared how close they lived to nuclear power plants when they were born with the same information in similar children who were cancer-free.
What’s the UK position on leukaemia and nuclear power?
In May 2011, the government’s advisory panel, COMARE, published their most recent report on childhood cancer risk and nuclear power plants. It analysed data from Great Britain and also gave its view on a recent German study that suggested a link.
The panel concluded that there was no evidence to support an increased risk of childhood leukaemia or other cancers in the vicinity of nuclear power plants in Great Britain.
COMARE recommended that the UK government keep a “watching brief” on health effects of living near nuclear power plants. To find out more read the Behind the Headlines report, Nuclear power 'not source of leukaemia'.
The researchers found no link between how close the children lived to the plants at birth and their risk of childhood leukaemia or non-Hodgkin lymphoma
The study benefits from using data on a large number of cases from across Great Britain over a long period. This increases the chance that they would be able to identify a link if one existed.
However, the results may be influenced by factors the researchers could not measure or take into account in their analyses. And while the number of cases analysed was large, not many people live near to nuclear power plants in the UK, which would make it more difficult to detect an effect if there was one.
This new UK evidence is in agreement with the most recent report from the UK’s Committee on Medical Aspects of Radiation in the Environment (COMARE) – see box above right.
The study authors and other sources have reasonably concluded that although the new UK findings are reassuring, it makes sense to continue monitoring to ensure that, if there is any risk, it will be detected.
Where did the story come from?
The study was carried out by researchers from University of Oxford and the University of Manchester. The work of the Childhood Cancer Research Group (CCRG) has been supported by the charity CHILDREN with CANCER (UK), the Scottish Government, and the Department of Health for England. One of the study authors was supported on the project by a legacy left in a will. The study was published in the peer-reviewed British Journal of Cancer.
The BBC News site covers this story in a balanced way.
What kind of research was this?
This was a case-control study which looked at whether there is a link between living near a nuclear power plant and leukaemia in young children.
A possible link between childhood cancer and nuclear power first came to public attention following a television report in the 1980s. This report suggested that there were more cases of cancer than expected in young people in the vicinity of what is now known as the Sellafield nuclear power plant. This led to the setting up of the Committee on Medical Aspects of Radiation in the Environment (COMARE), which analyses data on rates of cancer in children in the areas around nuclear plants in Great Britain.
A report from COMARE in 2005 found that although a number of excess cases of some kinds of childhood cancer were found for nuclear sites whose main function was not the generation of electricity they “found no evidence of excess numbers of cases in any local 25 km area” for 13 nuclear power stations. A 2011 COMARE report assessing published research and analysing British data concluded that “in spite of its limitations, the geographical analysis of British data is suggestive of a risk estimate for childhood leukaemia associated with proximity to an nuclear power plant that is extremely small, if not actually zero.”
There has been criticism that the UK research has so far specifically looked at geographical areas and the incidence of cancer in these areas. Results of this type of study are limited by the fact that childhood cancers are so uncommon that each area is likely to only have a few cases, and differences between areas may be hard to detect. Results may also be influenced by the fact that people move in and out of the areas and may be lost to the study.
In the current study, researchers used a case-control approach to assess the possibility of a link. This type of study is good for assessing potential causes of rare diseases, such as the childhood cancers. This is because the case-control approach allows researchers to gather together a larger group of individuals with the disease (cases) than would be found in a single area, and compare their past exposures with those of individuals without the disease (controls).
A recent case-control study from Germany found that young children living within 5km of a nuclear power plant were at increased risk of developing leukaemia by age five when compared to other areas, but no difference was found for other cancers.
What did the research involve?
The researchers identified all children diagnosed with childhood leukaemia or non-Hodgkin lymphoma in Great Britain between 1962 and 2007 (cases) and matched them to children who did not have cancer (controls). They compared how close the cases and controls lived to nuclear power plants at birth. They also compared where children with childhood leukaemia or non-Hodgkin lymphoma lived at diagnosis with children who had other types of cancer.
To identify cases, researchers used data from the National Registry of Childhood Tumours. This registry records diagnoses of malignant disease and non-malignant tumours in the brain or spinal cord in children aged under 15 living in Great Britain. It is estimated to contain over 97% of all of these diagnoses in Great Britain since 1970, and to contain at least 99% of the leukaemia diagnoses for the period assessed by the study. This information was linked with birth data for children born in Great Britain.
The researchers selected a ‘control’ child of the same gender and approximate age (two weeks to six months’ difference) for each ‘case’ child from the same birth registry. These controls had to be cancer-free at the age at which their matched case had been diagnosed. The children’s home addresses at birth and diagnosis were obtained from the registries.
Thirteen nuclear power plants in mainland Britain were considered in the analysis. These were: