Incidence of leukaemia and other cancers in birth and schools cohorts in the Dounreay area.

OBJECTIVE To determine whether a raised incidence of leukaemia in the Dounreay area occurred in children born to local mothers (birth cohort) or in those who moved to the area after birth (schools cohort) and also whether any cases of cancer have occurred in children born near Dounreay who may have moved elsewhere. DESIGN Follow up study. SETTING Dounreay area of Caithness, Scotland. SUBJECTS 4144 children born in the area in the period 1969-88 and 1641 children who attended local schools in the same period but who had been born elsewhere. MAIN OUTCOME MEASURES Cancer registration records linked to birth and school records with computerised probability matching methods. RESULTS Five cancer registrations were traced from the birth cohort compared with 5.8 expected on the basis of national rates (observed to expected ratio 0.9, 95% confidence interval 0.3 to 2.0). All five cases were of leukaemia (2.3, 0.7 to 5.4). In the schools cohort three cases were found (2.1, 0.4 to 6.2), all of which were of leukaemia (6.7, 1.4 to 19.5). All eight children were resident in the Dounreay area at the time of diagnosis; thus no cases were found in children who were born in or had attended school in the study area but who subsequently moved away. CONCLUSION The raised incidence of leukaemia in both the birth and schools cohorts suggests that place of birth is not a more important factor than place of residence in the series of cases of leukaemia observed near Dounreay area.