title: Threshold limit values of the cadmium concentration in rice in the development of itai-itai disease using benchmark dose analysis.
abstract: The aim of this study was to estimate the benchmark dose (BMD) as the threshold limit level of the cadmium (Cd) concentration in rice for itai-itai disease and/or suspected disease; it was based on the data that previously evaluated the association for such diseases with the Cd concentration in rice by using a logistic regression model. From 1971 to 1976, a total of 2446 rice samples were analyzed across the 88 hamlets in the Jinzu river basin. The mean Cd concentration in rice in each hamlet was used as the index of external Cd exposure of the entire population of the hamlet. We employed the incidence of itai-itai disease and/or suspected disease obtained from the available 55 hamlets. As the threshold, the lower limit of the BMD (BMDL) of the Cd concentration in rice for itai-itai disease and/or suspected disease was estimated using a logistic model, setting the benchmark response at 1% or 2%. The estimated BMDLs of the Cd concentration in rice for itai-itai disease and/or suspected disease were 0.62-0.76 and 0.27-0.56 mg kg-1in men and women, respectively. The lowest BMDL was 0.27 mg kg-1in women. In the present study, the threshold limit level of the Cd concentration in rice for itai-itai disease, which is the most severe form of chronic Cd poisoning, was estimated for the first time. This result provides important information about the worldwide standard for the Cd concentration in rice. Copyright © 2017 John Wiley & Sons, Ltd.
authors.affiliation: Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nogawa
authors.affiliation: Department of Social and Environmental Medicine, Kanazawa Medical University, Ishikawa, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Sakurai
authors.affiliation: Department of Social and Environmental Medicine, Kanazawa Medical University, Ishikawa, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Ishizaki
authors.affiliation: Department of Community Health Nursing, Kanazawa University School of Health Sciences, Ishikawa, Japan.
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Kido
authors.affiliation: Department of Epidemiology and Public Health, Kanazawa Medical University, Ishikawa, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nakagawa
authors.affiliation: Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasushi
authors.identifier: 0000-0003-3612-2395
authors.initials: Y
authors.lastname: Suwazono
mesh_terms: D019985:Benchmarking; D002104:Cadmium / Q000032:analysis*; D002105:Cadmium Poisoning / Q000453:epidemiology / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D002523:Edible Grain / Q000737:chemistry*; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male; D012275:Oryza / Q000737:chemistry*; D015995:Prevalence; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium
keywords: benchmark dose; itai-itai disease; rice cadmium concentration; risk assessment; threshold limit value