title: Biological half-life of cadmium in the urine of inhabitants after cessation of cadmium exposure.
abstract: We investigated the biological half-life of the urinary cadmium concentration (U-Cd) based on a 24-year follow-up study after cessation of cadmium exposure in a cadmium-polluted area. Spot urine samples were obtained from all inhabitants in this area in 1979, 1986, 1991, 1999 and 2003. Biological half-life was calculated in the inhabitants whose U-Cd was more than 5 microg l(-1) (9 men and 12 women) or 5 microg g(-1) creatinine (9 men and 19 women) using a one-compartment model. The estimated half-life and 95% confidence intervals were 13.6 years (9.0-28.2 years) and 13.9 years (9.6-25.6 years) for unadjusted U-Cd in men and women, respectively. For creatinine-adjusted U-Cd, they were 14.2 years (11.2-19.4 years) and 23.5 years (17.7-35.0 years) in men and women, respectively. The biological half-lives of U-Cd obtained in this study were identical with the values of total body burden determined by a different method.
authors.affiliation: Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan. suwa@faculty.chiba-u.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Suwazono
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Kido
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Muneko
authors.initials: M
authors.lastname: Nishijo
authors.forename: Ryumon
authors.initials: R
authors.lastname: Honda
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Mirei
authors.initials: M
authors.lastname: Dochi
authors.forename: Koji
authors.initials: K
authors.lastname: Nogawa