A case-control study of non-T cell acute lymphoblastic leukaemia of children in Hokkaido, Japan.

STUDY OBJECTIVE: The purpose of the study was to investigate factors associated with the occurrence of childhood acute lymphoblastic leukaemia in cases identified as of non-T cell type, stage I-IV. DESIGN: The study was a case-control investigation. Data were obtained by interview with parents of cases and controls. SETTING: The study was community based and was carried out in Hokkaido, Japan. SUBJECTS: 63 cases were identified. Controls (two for each case) were matched for sex, age and place of residence. MEASUREMENTS AND MAIN RESULTS: In univariate analysis, BCG vaccination, measles infection, measles vaccination, atopy, hip x ray, and milk intake of mother during pregnancy had significantly low odds ratios (ie, were less likely to be associated with leukaemia), while dental x rays for carious teeth and contact with animals at time of diagnosis had high odds ratios (more likely to be associated with leukaemia). In conditional logistic regression analysis employing these seven factors, measles infection/vaccination, BCG, atopy and dental x ray remained significant. CONCLUSIONS: Leukaemia subtypes are likely to have specific aetiologies. Future epidemiological research in leukaemia should take this into account.