Danish children who have lived in buildings with high levels of radon are at an increased risk of developing so-called acute lymphatic leukaemia, which is the most common type of leukaemia in children. Risø DTU has contributed to the new scientific study. Risø scientists have in the past measured and analysed radon in Danish homes, and the data have now been used in connection with a new study of the correlation between radon and childhood cancer headed by the Danish Cancer Society’s Institute of Cancer Epidemiology.
The study comprised 2,400 Danish children below the age of 15 who in the period 1968-1994 were diagnosed with leukaemia, brain tumours or malignant lymphomas. By means of the CPR register and the local registration offices, researchers succeeded in finding the addresses where the children had lived.
Radon levels were determined by Risø DTU by means of a new statistical model. The model is based on knowledge about the correlation between radon and geological factors and building characteristics accumulated in connection with a nationwide study of radon in Danish homes conducted in 2001 by Risø and the National Institute of Radiation Hygiene (SIS) and the Geological Survey of Denmark and Greenland (GEUS).
The soil type was determined at each of the addresses by means of digital soil maps. Information was obtained about basements, building materials and other factors which affect radon levels, and by means of the newly developed model, these data were converted into calculated radon levels in the children’s homes. The model was then tested against an independent set of data covering 758 buildings with known radon levels.
“Looking at our earlier measurements and our knowledge about the conditions where the children had lived provided us with a sound statistical basis on which to assess the radon levels to which the children with cancer had been exposed. We were able to include virtually all the buildings without having to ask anybody whether they wanted to be part of the study. In this way, we avoided creating unnecessary worry among the affected families,” says Senior Scientist Claus E. Andersen.
Findings
The study showed a so-called statistically significant correlation between radon exposure and acute lymphatic leukaemia, and if correct, this means that approx. 9 per cent of all cases of acute lymphatic leukaemia diagnosed in children in Denmark a year are caused by radon in the home, corresponding to approx. 3-4 cases a year.
It is known already that radon in the home increases the risk of lung cancer so the new findings on childhood leukaemia is yet another good reason for reducing radon levels in Danish homes.
Read more at the Danish Cancer Society website.
Make a simple assessment of radon levels in your own home
Radon is a breakdown product of uranium, which is one of the radioactive elements. Uranium is everywhere in the ground so people cannot avoid coming into contact with radon. Radon is also present in buildings in different levels, depending among other things on the type of soil and the building characteristics.
On the basis of information about 8 factors, you yourself can make a simple assessment of the radon level in your home. The calculations can be made at the Risø website.
Facts about radon
The following factors increase the probability of increased radon levels in the home:
- Rocks and moraine clay in the subsoil
- Foundations sitting directly on the ground, i.e. no basement
- Permeable foundations
- Little air circulation (airless building, poor ventilation)
- Location on Zealand, the islands or Bornholm
Radon is odourless, colourless and tasteless.
The average radon level in Danish homes is approx. double the level in Britain and the Netherlands, slightly higher than in the USA and Canada, but only half the average level measured in Sweden and Finland.
The study was carried out by:
- The Institute of Cancer Epidemiology, Danish Cancer Society
- Radiation Research Department, Risø DTU
- National Institute of Radiation Hygiene, National Board of Health
- National Survey and Cadastre Denmark, Danish Ministry of the Environment
- Geological Survey of Denmark and Greenland, Danish Ministry of Climate and Energy
The study has received funding from:
- Danish Ministry of the Interior and Health’s Research Centre for Environmental Health (ISMF)
- Nykredit
- Østifternes fond
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