Space-time clustering of glioma cannot be attributed to specific histological subgroups.
We previously showed that infectious exposures may be involved in the aetiology of adult glioma, by analysing for space-time clustering using population-based data from the South of the Netherlands. Here we extended these analyses and describe in detail the space-time clustering patterns in glioma subgroups, gender and age-categories. 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. We used the spatial coordinates of the addresses at diagnosis in the analyses. 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 analysed by a second order procedure based on K-functions. There was only statistically significant space-time clustering for oligodendroglioma. Clustering was present for adults aged 30-54 years and was more pronounced among males. Given the low prior probability of an infectious aetiology for this specific subgroup, these results should probably be interpreted as false-positive. We conclude that space-time clustering of glioma cannot be attributed to a specific glioma subgroup. The observed clustering in our previous study is therefore probably an overall effect within and between glioma subgroups.
Department of Neurology, St. Elisabeth Hospital, Tilburg, The Netherlands.
M P W A
MP
Houben
J W W
JW
Coebergh
J M
JM
Birch
C C
CC
Tijssen
C M
CM
van Duijn
R J Q
RJ
McNally
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001254:Astrocytoma / Q000145:classification / Q000453:epidemiology; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000382:microbiology; D004806:Ependymoma / Q000453:epidemiology; D005260:Female; D040362:Geographic Information Systems; D005843:Geography; D005910:Glioma / Q000145:classification / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D009837:Oligodendroglioma / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors; D017678:Sex Distribution; D013029:Space-Time Clustering