title: Estimation of benchmark dose for renal dysfunction in a cadmium non-polluted area in Japan.
abstract: Previously, the association between urinary cadmium (Cd) concentration and indicators of renal dysfunction, including beta(2)-microglobulin (beta(2)-MG), total protein and N-acetyl-beta-D-glucosaminidase (NAG) were investigated in 1270 inhabitants > or = 50 years of age (547 men, 723 women) in a Cd non-polluted area in Japan and showed that a dose-response relationship existed between renal effects and Cd exposure in the general environment without any known Cd pollution. However, the threshold levels of urinary Cd could not be estimated at that time. In the present study, the threshold levels of urinary Cd were estimated as the benchmark dose low (BMDL) using the benchmark dose (BMD) approach. Urinary Cd excretion was divided into 6-7 categories, and an abnormality rate was calculated for each. Cut-off values for urinary substances were defined as corresponding to the 84% upper limit values, which were calculated from 2034 persons who had been living in the non-polluted areas and did not smoke. Then the BMD and BMDL were calculated using a log-logistic model. The values of BMD and BMDL for all urinary substances could be calculated. The BMDL for the 84% cut-off value of beta(2)-MG, setting an abnormal value at 5%, was 2.0 microg g(-1) creatinine (cr) in men and 1.6 microg g(-1) cr in women. In conclusion, the present study demonstrated that the threshold level of urinary Cd could be estimated in people living in the general environment without any known Cd-pollution in Japan, and the value was inferred to be almost the same as that in Belgium and Sweden.
authors.affiliation: Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, Japan. ekoba@faculty.chiba-u.jp
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Suwazono
authors.forename: Mirei
authors.initials: M
authors.lastname: Uetani
authors.forename: Takeya
authors.initials: T
authors.lastname: Inaba
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Oishi
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Kido
authors.forename: Muneko
authors.initials: M
authors.lastname: Nishijo
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Koji
authors.initials: K
authors.lastname: Nogawa
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine; D019985:Benchmarking; D015415:Biomarkers / Q000652:urine; D002104:Cadmium / Q000009:adverse effects* / Q000652:urine; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007674:Kidney Diseases / Q000453:epidemiology* / Q000209:etiology / Q000652:urine; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011507:Proteinuria / Q000453:epidemiology* / Q000209:etiology / Q000652:urine; D018570:Risk Assessment; D001613:beta 2-Microglobulin / Q000652:urine
chemical_list: D015415:Biomarkers; D001613:beta 2-Microglobulin; D002104:Cadmium; D000118:Acetylglucosaminidase