Space-time clustering of acute lymphoblastic leukaemia in parts of the UK (1984-1993)

Age-related differences in the incidence and immunological subtypes of acut e lymphoblastic leukaemia (ALL) suggest that it may be composed of more tha n one disease entity, each with different aetiologies. Childhood leukaemia (of which the majority of cases are ALL) has been suspected of having an in fectious aetiology, but few studies have systematically examined ALL for cl ustering by age group. The aim of this study was to examine ALL for evidenc e of space-time clustering of date and place of diagnosis by age group. Kno x space-time analysis was carried out separately for three different age gr oups: childhood (0-14 years), young adult (15-34 years) and older adults (3 5-79 years). Data on 968 cases of ALL aged 0-79 years, arising during 1984- 1993 in the areas covered by a specialist population based register of leuk aemias and lymphomas in parts of the U.K., were used in the analysis. Space -time clustering of diagnoses was limited to children aged 0-14 years. It w as more prominent in those diagnosed in the period 1984-1988, than in those diagnosed in 1989-1993. The clustering may indicate an infectious aetiolog y for childhood ALL, or could be the result of episodic exposures to some e nvironmental hazard. (C) 1999 Elsevier Science Ltd. All rights reserved.