A Koushik1, W D King, J R McLaughlin. 1. Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada.
Abstract
OBJECTIVE: To examine the association between population mixing and the incidence of childhood leukemia, specifically the acute lymphocytic leukemia (ALL) subtype among young children. METHODS: This ecologic study was based on incidence rates of leukemia in children aged 0-14 years. The Ontario Cancer Registry was used to identify the residence of 1394 leukemia cases between 1978 and 1992. Ecologic units were composed of census subdivisions in a 5-year period. Percent population change, determined from the Census of Canada, was employed as a measure of population mixing. The relationship between population mixing and childhood leukemia was examined separately after stratifying by the level of geographic isolation, defined according to urban-rural status. Analyses were also conducted separately in specific age groups and for the ALL subtype. RESULTS: Population growth in rural areas was associated with an increased incidence of leukemia, particularly for the ALL subtype in children aged 0-4 years (rate ratio = 1.8, 95% confidence interval 1.1-2.8, for a greater than 20% population change relative to no increase in population). In contrast, an elevated risk due to population mixing was not observed in urban areas. CONCLUSIONS: Results from this study are consistent with results from similar studies conducted in the United Kingdom, which are suggestive of a role for an infectious agent in the etiology of childhood leukemia, as proposed in the Kinlen hypothesis.
OBJECTIVE: To examine the association between population mixing and the incidence of childhood leukemia, specifically the acute lymphocytic leukemia (ALL) subtype among young children. METHODS: This ecologic study was based on incidence rates of leukemia in children aged 0-14 years. The Ontario Cancer Registry was used to identify the residence of 1394 leukemia cases between 1978 and 1992. Ecologic units were composed of census subdivisions in a 5-year period. Percent population change, determined from the Census of Canada, was employed as a measure of population mixing. The relationship between population mixing and childhood leukemia was examined separately after stratifying by the level of geographic isolation, defined according to urban-rural status. Analyses were also conducted separately in specific age groups and for the ALL subtype. RESULTS: Population growth in rural areas was associated with an increased incidence of leukemia, particularly for the ALL subtype in children aged 0-4 years (rate ratio = 1.8, 95% confidence interval 1.1-2.8, for a greater than 20% population change relative to no increase in population). In contrast, an elevated risk due to population mixing was not observed in urban areas. CONCLUSIONS: Results from this study are consistent with results from similar studies conducted in the United Kingdom, which are suggestive of a role for an infectious agent in the etiology of childhood leukemia, as proposed in the Kinlen hypothesis.
Authors: Judith E Lupatsch; Claudia E Kuehni; Felix Niggli; Roland A Ammann; Matthias Egger; Ben D Spycher Journal: Eur J Epidemiol Date: 2015-05-26 Impact factor: 8.082
Authors: Judith E Lupatsch; Christian Kreis; Marcel Zwahlen; Felix Niggli; Roland A Ammann; Claudia E Kuehni; Ben D Spycher Journal: Eur J Epidemiol Date: 2016-06-01 Impact factor: 8.082