An infectious aetiology for childhood brain tumours? Evidence from space-time clustering and seasonality analyses.
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.
McNally
R J Q
RJ
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
Cairns
D P
DP
Eden
O B
OB
Alexander
F E
FE
Taylor
G M
GM
Kelsey
A M
AM
Birch
J M
JM
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