title: An infectious aetiology for childhood brain tumours? Evidence from space-time clustering and seasonality analyses.
abstract: To investigate whether infections or other environmental exposures may be involved in the aetiology of childhood central nervous system tumours, we have analysed for space-time clustering and seasonality using population-based data from the North West of England for the period 1954 to 1998. Knox tests for space-time interactions between cases were applied with fixed thresholds of close in space, <5 km, and close in time, <1 year apart. Addresses at birth and diagnosis were used. Tests were repeated replacing geographical distance with distance to the Nth nearest neighbour. N was chosen such that the mean distance was 5 km. Data were also examined by a second order procedure based on K-functions. Tests for heterogeneity and Edwards' test for sinusoidal variation were applied to examine changes of incidence with month of birth or diagnosis. There was strong evidence of space-time clustering, particularly involving cases of astrocytoma and ependymoma. Analyses of seasonal variation showed excesses of cases born in the late Autumn or Winter. Results are consistent with a role for infections in a proportion of cases from these diagnostic groups. Further studies are needed to identify putative infectious agents.
authors.affiliation: Cancer Research UK Paediatric & Familial Cancer Research Group, Central Manchester and Manchester Children's University Hospitals NHS Trust, Manchester M27 4HA, UK. richard.mcnally@man.ac.uk
authors.forename: R J Q
authors.initials: RJ
authors.lastname: McNally
authors.forename: D P
authors.initials: DP
authors.lastname: Cairns
authors.forename: O B
authors.initials: OB
authors.lastname: Eden
authors.forename: F E
authors.initials: FE
authors.lastname: Alexander
authors.forename: G M
authors.initials: GM
authors.lastname: Taylor
authors.forename: A M
authors.initials: AM
authors.lastname: Kelsey
authors.forename: J M
authors.initials: JM
authors.lastname: Birch
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology; D001719:Birth Certificates; D001932:Brain Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007239:Infections / Q000150:complications*; D008297:Male; D012621:Seasons