A quest for seasonality in presentation of leukaemia and non-Hodgkin's lymphoma.

The literature on presentation of seasonality of leukaemia fails to provide clear conclusions. Using the Data Collection Study organised by the Leukaemia Research Fund (LRF) Centre for Clinical Epidemiology, University of Leeds, this question was re-examined. This data has a high level of ascertainment and is population based. The results were mainly negative, there being no fit to a sinusoidal curve (Cosinor analysis) in any part of the data. Using normal approximation to Poisson there were individual months with positive findings. Such a method could not be specifically depended on to provide reliable conclusions, nevertheless, further work in this area is justified. Non-Hodgkin's lymphoma was also examined but again with mainly negative findings.