Incidence of childhood leukaemia in The Netherlands (1973-1980).

The childhood leukaemia incidence rate for the Netherlands was estimated at 3.11 per 100.000 children (aged 0-15 year) per year, based on a complete nation-wide childhood leukaemia registry comprising the period 1973-1980. Acute lymphocytic leukaemia (ALL) accounted for 82.4% of the patients, acute non-lymphocytic leukaemia for 13.6% and chronic myeloid leukaemia for 2.9%. ALL occurred more frequently in boys (sex ratio 1.2). The highest ALL rate was observed in the 3-4 year age group. These figures corresponded with the data of the Manchester Children's Tumour Registry. Neither the incidence rates according to year of diagnosis nor the incidence rates according to year of birth showed a significant trend with time. The total leukaemia incidence rate in urban areas was somewhat higher than in rural areas. While the direct comparison of the incidence rate between these areas is not significant, the trend over the three categories of urbanisation is significant.