Leon Jonker, Chris Brewer and Michael Williams
Background: In recent years, incidences of thyroid cancer have increased in developed countries; one of the known risk factors for thyroid cancer is exposure to radioiodine. Previous research by Bowlt and Tiplady  has shown an inverse link between radioactive iodine levels contained in thyroid tissue of deceased inhabitants and the distance they lived from the Sellafield nuclear facility in Cumbria, UK.
Objectives: The present study aimed to determine what thyroid cancer incidences were in the regional localities in Cumbria for the last decade.
Methods: An ethics-approved retrospective cohort study in which age-standardised incidence of thyroid cancer per 100,000 population was compared between localities within Cumbria and with UK average figures.
Conclusions: The present study shows that the apparent lower incidence of thyroid cancer in West Cumbria has persisted, although due to the limited number of thyroid cancers diagnosed, a statistically significant difference was not observed. Further research – potentially involving populations living near sources of radioiodine emission - is indicated to investigate if there are any mechanisms that underlie this apparent trend.