title: Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?
abstract: One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (131I) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the 131I-related risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiation-related risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer.
authors.affiliation: The International fund "Help for patients with radiation-induced thyroid cancer "Arnica", Minsk, Belarus; Department of Endocrinology, Belarusian Medical Academy for Postgraduate Education, Minsk, Belarus.
authors.forename: Valentina M
authors.initials: VM
authors.lastname: Drozd
authors.affiliation: Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University, Sakamoto, Nagasaki, Japan.
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Saenko
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, United States Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Alina V
authors.initials: AV
authors.lastname: Brenner
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, United States Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Drozdovitch
authors.affiliation: Laboratory of Hydrogeology and Hydroecology, Institute for Nature Management of the National Academy of Sciences, Minsk, Belarus.
authors.forename: Vasilii I
authors.initials: VI
authors.lastname: Pashkevich
authors.affiliation: Laboratory of Hydrogeology and Hydroecology, Institute for Nature Management of the National Academy of Sciences, Minsk, Belarus.
authors.forename: Anatoliy V
authors.initials: AV
authors.lastname: Kudelsky
authors.affiliation: Department of Oncology, Belarusian Medical Academy for Postgraduate Education, Minsk, Belarus.
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Demidchik
authors.affiliation: Project Chernobyl, Brooklyn, New York, United States of America.
authors.forename: Igor
authors.initials: I
authors.lastname: Branovan
authors.affiliation: Project Chernobyl, Brooklyn, New York, United States of America.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Shiglik
authors.affiliation: Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Sakamoto, Nagasaki, Japan.
authors.forename: Tatiana I
authors.initials: TI
authors.lastname: Rogounovitch
authors.affiliation: Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University, Sakamoto, Nagasaki, Japan; Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Sakamoto, Nagasaki, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Yamashita
authors.affiliation: The International fund "Help for patients with radiation-induced thyroid cancer "Arnica", Minsk, Belarus; Clinic and Polyclinic of Nuclear Medicine, University of Wuerzburg, Wuerzburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Biko
authors.affiliation: The International fund "Help for patients with radiation-induced thyroid cancer "Arnica", Minsk, Belarus; Clinic and Polyclinic of Nuclear Medicine, University of Wuerzburg, Wuerzburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Reiners
mesh_terms: D000293:Adolescent; D047852:Chernobyl Nuclear Accident; D002648:Child; D002675:Child, Preschool; D055088:Early Detection of Cancer; D004781:Environmental Exposure; D060587:Groundwater / Q000032:analysis; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D017613:Iodine Compounds / Q000032:analysis / Q000633:toxicity*; D007457:Iodine Radioisotopes / Q000032:analysis / Q000633:toxicity*; D009381:Neoplasms, Radiation-Induced / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D009566:Nitrates / Q000032:analysis / Q000633:toxicity*; D002094:Republic of Belarus / Q000453:epidemiology; D012307:Risk Factors; D012990:Soil Pollutants, Radioactive / Q000032:analysis; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D014463:Ultrasonography; D014875:Water Pollutants, Radioactive / Q000032:analysis / Q000633:toxicity*
chemical_list: D017613:Iodine Compounds; D007457:Iodine Radioisotopes; D009566:Nitrates; D012990:Soil Pollutants, Radioactive; D014875:Water Pollutants, Radioactive