title: Acute lymphoblastic leukemia incidence during socioeconomic transition: selective increase in children from 1 to 4 years.
abstract: Pre-school acute lymphoblastic leukemia (ALL) peak is consistent in developed but not in developing countries and its magnitude apparently correlates with the socioeconomic status. A population-based study describing ALL incidence during socioeconomic transition has been lacking. Central European post-communist countries (with very low foreign migration and centralized statistics) offer reliable data for the period before and during major socioeconomic changes. Population-based data on Czech ALL patients younger than 18 years were taken from two independent Czech national registries partially overlapping in time (1980-1998, n = 1236 and 1991-1999, n = 570). During the 1980s and 1990s, ALL incidence among children 1-4 years increased 1.5 times (P = 0.01). This increase was more prominent in females than in males (slopes 0.13 and 0.09, P values 0.03 and >0.05, respectively). No significant change was observed in other age groups (0, 5-9, 10-14, 15-17 years or all others combined). We discuss possible underlying socioeconomic factors including infant care and breast-feeding, hygiene, birth order, industry and pollution. Moreover, we try to pinpoint the immunophenotypic/molecular-genetic subsets of ALL that might be socioeconomically affected. Selective increase of ALL in children 1-4 years old provides epidemiological evidence that etiology and/or trigger mechanisms are different for a considerable proportion of these children and that these mechanisms are exogenous.
authors.affiliation: Institute of Immunology, 2nd Medical School, Charles University, Prague, Czech Republic.
authors.forename: O
authors.initials: O
authors.lastname: Hrusák
authors.forename: J
authors.initials: J
authors.lastname: Trka
authors.forename: J
authors.initials: J
authors.lastname: Zuna
authors.forename: A
authors.initials: A
authors.lastname: Poloucková
authors.forename: T
authors.initials: T
authors.lastname: Kalina
authors.forename: J
authors.initials: J
authors.lastname: Starý
mesh_terms: D017668:Age of Onset; D002675:Child, Preschool; D050676:Core Binding Factor Alpha 2 Subunit; D018153:Czech Republic / Q000453:epidemiology; D003710:Demography; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism; D011003:Ploidies; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012959:Socioeconomic Factors; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D016044:Fusion Proteins, bcr-abl; D051788:Myeloid-Lymphoid Leukemia Protein; D015514:Oncogene Proteins, Fusion; C113855:MLL-AF4 fusion protein, human; C102421:TEL-AML1 fusion protein; D000097764:ETS Translocation Variant 6 Protein