title: Reproducibility of urinary beta 2-microglobulin and cadmium excretion among residents in a cadmium-polluted area during a 3-year period.
abstract: To assess the measurement error by using single exposure measurement in epidemiologic studies, reproducibility of urinary beta 2-microglobulin and cadmium excretion was evaluated among persons exposed to environmental cadmium. We measured urinary beta 2-microglobulin concentrations in 47 subjects four times and urinary cadmium concentrations in 48 subjects twice, during a 3-year period. Between-person and within-person variance components of these variables were estimated using a random-effects one-way analysis of variance model. The intraclass correlation coefficient (ICC) for urinary beta 2-microglobulin concentration, when expressed as microg/g creatinine and microg/l, was 0.92 and 0.89, respectively. The ICC for standardized urinary cadmium concentration (expressed as microg/g creatinine) was 0.81, while it decreased to 0.33 without standardization. The findings suggest that single measurement of urinary beta 2-microglobulin and cadmium, when expressed as a function of creatinine, can reliably estimate average levels over at least a 3-year period. Standardization of concentration using urinary creatinine improved reproducibility especially for urinary cadmium excretion.
authors.affiliation: Department of Preventive Medicine and Health Promotion, Nagasaki University School of Medicine, Sakamoto, Japan. k-iwata@net.nagasaki-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Arisawa
authors.forename: A
authors.initials: A
authors.lastname: Nakano
authors.forename: S
authors.initials: S
authors.lastname: Honda
authors.forename: H
authors.initials: H
authors.lastname: Saito
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002104:Cadmium / Q000009:adverse effects / Q000592:standards / Q000652:urine*; D003404:Creatinine / Q000592:standards / Q000652:urine; D004785:Environmental Pollutants / Q000009:adverse effects / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012015:Reference Standards; D015203:Reproducibility of Results; D001613:beta 2-Microglobulin / Q000652:urine*
chemical_list: D004785:Environmental Pollutants; D001613:beta 2-Microglobulin; D002104:Cadmium; D003404:Creatinine