Risk Factors for Childhood Leukemia
Radiation Protection Dosimetry 132(2):107-274; 2008.
Content: Childhood leukemia is a heterogeneous disease and the most common malignancy in children accounting for around one third of all childhood cancer cases below the age of 15 years. The causes of most leukemias are still unknown, but both genetic and environmental factors have been implicated in the aetiology of the disease.
Ionizing radiation is regarded as an established environmental risk factor, found in epidemiological studies and confirmed by experimental data. At the same time data on an increased incidence of childhood leukemia near nuclear facilities are puzzling experts, because the exposures in relation to the case numbers are too low to be considered causal.
Non-ionizing radiation has been studied as a possible risk factor since more than 30 years. No carcinogenic potential of low-level fields (levels below ICNIRP recommendations) has been revealed in experimental studies. However, a consistent pattern of a two-fold increase in childhood leukemia is observed in epidemiological studies associated with average exposure to residential low-frequency magnetic fields above 0,3-0,4 µT. The epidemiological evidence is weakened by methodological limitations and no accepted or even plausible biophysical mechanism challenging the crucial question of causal relationship are currently available.
The apparent inconsistencies between empirical findings and the lack of supportive experimental data have to be considered in the light of other possible risk factors and of new data on the complex origin of childhood leukemia. A number of recent studies supports the hypothesis that initiation of the disease arises prenatally and that exposures before birth or early in life and/or an abnormal immune response play an important role in its further manifestation.
The international workshop brought together experts from different disciplines and backgrounds in order to summarize the current knowledge on all known risk factors and the recent hypothesis on the aetiology of childhood leukemia. The workshop serves the organizers and other experts in radiation protection to assess the statistical associations observed frequently or consistently at low dose/low level areas in epidemiological studies.
Table of Contents
Childhood leukemia
Peter Kaatsch and Andreas Mergenthaler
Incidence, time trends and regional variation of childhood leukaemia in Germany and Europe
Claudia Rossig and Heribert Juergens
Aetiology of childhood acute leukaemias: current status of knowledge
Anand P. Chokkalingam and Patricia A. Buffler
Genetic susceptibility to childhood leukaemia
Martin Schrappe
Risk-adapted stratification and treatment of childhood acute lymphoblastic leukaemia
Uncertainties and challenges
Colin R. Muirhead
Exposure assessment: implications for epidemiological studies of ionizing radiation
L. Kheifets and S. Oksuzyan
Exposure assessment and other challenges in non-ionizing radiation studies of childhood leukaemia
Beate Ritz and Rudolph P. Rull
Assessment of environmental exposures from agricultural pesticides in childhood leukaemia studies: challenges and opportunities
Environmental risk factors: Ionizing radiation
Epidemiological studies - high (single) doses
M. P. Little
Leukaemia following childhood radiation exposure in the Japanese atomic bomb survivors and in medically exposed groups
Richard Wakeford
Childhood leukaemia following medical diagnostic exposure to ionizing radiation in utero or after birth
Epidemiological studies - chronic exposure at low doses
Ole Raaschou-Nielsen
Indoor radon and childhood leukaemia
D. Laurier S. Jacob, M. O. Bernier, K. Leuraud, C. Metz, E. Samson, and P. Laloi
Epidemiological studies of leukaemia in children and young adults around nuclear facilities: a critical review
J. F. Bithell T. J. Keegan, M. E. Kroll, M. F. G. Murphy, and T. J. Vincent
Childhood leukaemia near British nuclear installations: methodological issues and recent results
Bernd Grosche
The “Kinderkrebs in der Umgebung von Kernkraftwerken” study: results put into perspective
Environmental risk factors: Non-ionizing radiation
J. Schüz and A. Ahlbom
Exposure to electromagnetic fields and the risk of childhood leukaemia: a review
Environmental risk factors: Pesticides, other chemicals
Catherine Metayer and Patricia A. Buffler
Residential exposures to pesticides and childhood leukaemia
Claire Infante-Rivard
Chemical risk factors and childhood leukaemia: a review of recent studies
Jukka Juutilainen
Do electromagnetic fields enhance the effects of environmental carcinogens?
Prenatal parental exposures
Patricia A. McKinney, Olaide Y. Raji, Martie van Tongeren, and Richard G. Feltbower
The UK Childhood Cancer Study: maternal occupational exposures and childhood leukaemia and lymphoma
Geral Draper
Preconception exposures to potential germ-cell mutagens
Martin Adam, Cornelia E. Rebholz, Matthias Egger, Marcel Zwahlen, and Claudia E. Kuehni
Childhood leukaemia and socioeconomic status: what is the evidence?
Nicholas de Klerk and Elizabeth Milne
Overview of recent studies on childhood leukaemia, intra-uterine growth and diet
Hypotheses on dysregulated immune responses to common infections
Kevin Y. Urayama, Xiaomei Ma, and Patricia A. Buffler
Exposure to infections through day-care attendance and risk of childhood leukaemia
Graham Richard Law
Host, family and community proxies for infections potentially associated with leukaemia
Christopher Portier
Discussion and summary
Peter Kaatsch and Andreas Mergenthaler
Incidence, time trends and regional variation of childhood leukaemia in Germany and Europe
Claudia Rossig and Heribert Juergens
Aetiology of childhood acute leukaemias: current status of knowledge
Anand P. Chokkalingam and Patricia A. Buffler
Genetic susceptibility to childhood leukaemia
Martin Schrappe
Risk-adapted stratification and treatment of childhood acute lymphoblastic leukaemia
Uncertainties and challenges
Colin R. Muirhead
Exposure assessment: implications for epidemiological studies of ionizing radiation
L. Kheifets and S. Oksuzyan
Exposure assessment and other challenges in non-ionizing radiation studies of childhood leukaemia
Beate Ritz and Rudolph P. Rull
Assessment of environmental exposures from agricultural pesticides in childhood leukaemia studies: challenges and opportunities
Environmental risk factors: Ionizing radiation
Epidemiological studies - high (single) doses
M. P. Little
Leukaemia following childhood radiation exposure in the Japanese atomic bomb survivors and in medically exposed groups
Richard Wakeford
Childhood leukaemia following medical diagnostic exposure to ionizing radiation in utero or after birth
Epidemiological studies - chronic exposure at low doses
Ole Raaschou-Nielsen
Indoor radon and childhood leukaemia
D. Laurier S. Jacob, M. O. Bernier, K. Leuraud, C. Metz, E. Samson, and P. Laloi
Epidemiological studies of leukaemia in children and young adults around nuclear facilities: a critical review
J. F. Bithell T. J. Keegan, M. E. Kroll, M. F. G. Murphy, and T. J. Vincent
Childhood leukaemia near British nuclear installations: methodological issues and recent results
Bernd Grosche
The “Kinderkrebs in der Umgebung von Kernkraftwerken” study: results put into perspective
Environmental risk factors: Non-ionizing radiation
J. Schüz and A. Ahlbom
Exposure to electromagnetic fields and the risk of childhood leukaemia: a review
Environmental risk factors: Pesticides, other chemicals
Catherine Metayer and Patricia A. Buffler
Residential exposures to pesticides and childhood leukaemia
Claire Infante-Rivard
Chemical risk factors and childhood leukaemia: a review of recent studies
Jukka Juutilainen
Do electromagnetic fields enhance the effects of environmental carcinogens?
Prenatal parental exposures
Patricia A. McKinney, Olaide Y. Raji, Martie van Tongeren, and Richard G. Feltbower
The UK Childhood Cancer Study: maternal occupational exposures and childhood leukaemia and lymphoma
Geral Draper
Preconception exposures to potential germ-cell mutagens
Martin Adam, Cornelia E. Rebholz, Matthias Egger, Marcel Zwahlen, and Claudia E. Kuehni
Childhood leukaemia and socioeconomic status: what is the evidence?
Nicholas de Klerk and Elizabeth Milne
Overview of recent studies on childhood leukaemia, intra-uterine growth and diet
Hypotheses on dysregulated immune responses to common infections
Kevin Y. Urayama, Xiaomei Ma, and Patricia A. Buffler
Exposure to infections through day-care attendance and risk of childhood leukaemia
Graham Richard Law
Host, family and community proxies for infections potentially associated with leukaemia
Christopher Portier
Discussion and summary