Community lifestyle characteristics and lymphoid malignancies in young people in the UK.

Data from a specialist registry of haematopoietic malignancies in England and Wales (1984-1988) have been analysed to investigate variations of incidence by age and diagnostic subtype of lymphoid malignancies in young people (aged 0-24 years). Attention has been focussed on the role of community lifestyle indicators for small areas, derived from routine sources, in an ecological analysis. The predominant conditions were acute lymphoblastic leukaemia (ALL)--42.4%, and Hodgkin's disease (HD)--37.5%. Lowest overall incidence at approximately 8 years of age corresponded to the termination of the childhood peak for ALL. Opposite trends of incidence rates with distance from urban centres (urban distance) were observed for the two age groups: odds ratios (OR) for areas greater than 20 km from towns and cities were 1.46 (95% confidence interval 1.01-2.12) for ages 0-7 and 0.75 (95% confidence interval 0.56-0.99) for ages 8-24. For the younger group this was entirely attributable to ALL. HD, which was dominant in the older group, had highest incidence in connurbations but the gradient of risk for older onset ALL followed the overall pattern for this age group. A positive relationship with socioeconomic status was evident for both age groups but this was considerably stronger for the older cases (OR = 1.16, 95% confidence interval 1.01-1.33) than for the younger for whom it was not independent of urban distance. These results display an association between expression of lymphoid malignancies in young people and urban distance which is not attributable to socioeconomic status; for urban distances the distribution is shifted towards ALL and towards younger age at onset.