Childhood leukaemia and non-Hodgkins lymphoma in young people living close to nuclear reprocessing sites.

An increased incidence of leukaemia and NHL has been recorded close to Britain's two nuclear reprocessing sites at Sellafield in West Cumbria and Dounreay in Northern Scotland. Two hypotheses have been advanced to explain the excesses - paternal preconceptional irradiation (PPI) and an infective basis promoted by population mixing. Subsequent studies have provided no support for the PPI hypothesis and have also shown that this was derived from the analysis of a sub-group. In contrast, support for the population mixing hypothesis has come from a series of studies of residential and occupational situations. One of these showed that the excess near Dounreay was part of a wider increase in rural areas of Scotland affected by the unusual mixing associated with away-from-home work in the North Sea oil industry, being more marked in areas of relatively high social class. It is probable that the excess in Seascale is due to related demographic factors, this parish being extreme in its high social class, geographic isolation and its proximity to Sellafield, the largest, most changing industrial site in rural Britain.