TY - JOUR
TI - Space-time clustering of childhood leukaemia in Greece: Evidence
supporting a viral aetiology
AU - Petridou, E
AU - Revinthi, K
AU - Alexander, FE
AU - Haidas, S and
AU - Koliouskas, D
AU - Kosmidis, H
AU - Piperopoulou, F
AU - Tzortzatou, F and
AU - Trichopoulos, D
JO - British Journal of Cancer
PY - 1996
VL - 73
TODO - 10
SP - 1278-1283
PB - STOCKTON PRESS
SN - 0007-0920, 1532-1827
TODO - 10.1038/bjc.1996.245
TODO - space-time clustering; childhood leukaemia; viral aetiology
TODO - The method introduced by Knox for evaluation of space-time clustering
has been applied to 872 cases of childhood (0-14 year old) leukaemia
diagnosed in Greece over the 10 year period 1980-89. Greek towns are
characterised by substantial population mixing due to internal
migration, whereas there is relative isolation in mountainous rural
areas. Predetermined space (5 km) and time (1 year) limits were used on
the basis of previous reports in order to define the clustering cell.
There is highly significant evidence for clustering of childhood
leukaemia in Greece as a whole, the observed number of pairs that are
close in both space and time exceeding the expected number by 5.2%
(P=0.004). The excess is particularly evident for leukaemia cases in 0
to 4-year-old children, among whom the observed number of pairs that are
close in both space acid time exceeded the expected number by 9.4%
(P=0.004). There is no evidence of space-time clustering for leukaemia
cases older than 5 years. The overall pattern is descriptively similar
in urban and semiurban areas and is especially marked for acute
lymphoblastic leukaemia at the childhood peak ages (2-4 years) with an
excess of 19% (P=0.0006). In the rural population there is evidence for
clustering of cases belonging to older and broader age groups, a
phenomenon compatible a with a delay in the development of herd immunity
against putative infectious aetiological agents. The findings of the
present study provide support For the hypothesis that a substantial
proportion of cases of childhood leukaemia may arise as a rare sequel to
exposure to an agent or agents, most probably viral in nature.
ER -