Seasonality of birth for cancer in Northern England, UK

Environmental factors operating around the time of birth may influence the subsequent development of childhood cancer, particularly leukaemia. Certain factors may vary with season (e.g. infections), and we therefore investiga ted whether there was any evidence of seasonality of month of birth, based on data from 4199 children diagnosed with cancer under the age of 15 years. We extracted details of (i) children born 1960-95 and diagnosed 1968-95 fr om two population-based registries, covering the Northern (n = 2053) and Yo rkshire (n = 1977) Regional Health Authority and (ii) children born in Cumb ria 1950-93 and diagnosed anywhere in the UK before 1994 from a birth cohor t database (n = 397). The following diagnostic categories were analysed: 0- 14 years - all cancers, leukaemias, acute lymphoblastic leukaemias, central nervous system tumours, all other solid tumours; 1-6 years - leukaemias, a cute lymphoblastic leukaemias. Seasonal variation was tested using Walter a nd Elwood's test, and logistic regression analysis allowing for cyclical va riation in month of birth. No evidence of seasonality was present for any g roup except acute lymphoblastic leukaemia diagnosed among 1- to 6-year-olds . Seasonal trends varied by region: in the Northern and Cumbrian datasets, seasonality patterns were significant and similar (P < 0.05) with a predict ed peak in early spring, whereas in Yorkshire there was less strong evidenc e of seasonality (P = 0.08) with a peak predicted in late summer. These fin dings suggest that local seasonal environmental factors operating around th e time of birth are not associated with the totality of childhood cancer, b ut possible links with acute lymphoblastic leukaemia are supportive of a hy pothesis of an infectious aetiology.