title: Temporal variability of urinary cadmium in spot urine samples and first morning voids.
abstract: Cadmium is a carcinogenic heavy metal. Urinary levels of cadmium are considered to be an indicator of long-term body burden, as cadmium accumulates in the kidneys and has a half-life of at least 10 years. However, the temporal stability of the biomarker in urine samples from a non-occupationally exposed population has not been rigorously established. We used repeated measurements of urinary cadmium (U-Cd) in spot urine samples and first morning voids from two separate cohorts, to assess the temporal stability of the samples. Urine samples from two cohorts including individuals of both sexes were measured for cadmium and creatinine. The first cohort (Home Observation of Perinatal Exposure (HOPE)) consisted of 21 never-smokers, who provided four first morning urine samples 2-5 days apart, and one additional sample roughly 1 month later. The second cohort (World Trade Center-Health Program (WTC-HP)) consisted of 78 individuals, including 52 never-smokers, 22 former smokers and 4 current smokers, who provided 2 spot urine samples 6 months apart, on average. Intra-class correlation was computed for groups of replicates from each individual to assess temporal variability. The median creatinine-adjusted U-Cd level (0.19 and 0.21 μg/g in the HOPE and WTC-HP, respectively) was similar to levels recorded in the United States by the National Health and Nutrition Examination Survey. The intra-class correlation (ICC) was high (0.76 and 0.78 for HOPE and WTC-HP, respectively) and similar between cohorts, irrespective of whether samples were collected days or months apart. Both single spot or first morning urine cadmium samples show good to excellent reproducibility in low-exposure populations.
authors.affiliation: Program in Public Health, Department of Family, Population and Preventive Medicine, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Caterina
authors.initials: C
authors.lastname: Vacchi-Suzzi
authors.affiliation: Department of Family and Preventive Medicine, University of Utah, Salt Lake City, Utah 84108, USA.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Porucznik
authors.affiliation: Department of Family and Preventive Medicine, University of Utah, Salt Lake City, Utah 84108, USA.
authors.forename: Kyley J
authors.initials: KJ
authors.lastname: Cox
authors.affiliation: Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Hongshik
authors.initials: H
authors.lastname: Ahn
authors.affiliation: Analytical Sciences Department, Innovation, Technology and Development, RTI International, Research Triangle Park, North Carolina 27709, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Harrington
authors.affiliation: Analytical Sciences Department, Innovation, Technology and Development, RTI International, Research Triangle Park, North Carolina 27709, USA.
authors.forename: Keith E
authors.initials: KE
authors.lastname: Levine
authors.affiliation: Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Demple
authors.affiliation: Department of Pharmacology and Toxicology, Norris Cotton Cancer Center, Dartmouth Medical School, New Hampshire 03755, USA.|Department of Family and Community Medicine, Norris Cotton Cancer Center, Dartmouth Medical School, New Hampshire 03755, USA.
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Marsit
authors.affiliation: Department of Psychiatry, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Gonzalez
authors.affiliation: Department of Medicine, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Luft
authors.affiliation: Program in Public Health, Department of Family, Population and Preventive Medicine, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Jaymie R
authors.initials: JR
authors.lastname: Meliker
mesh_terms: D015415:Biomarkers / Q000652:urine*; D015992:Body Mass Index; D002104:Cadmium / Q000652:urine*; D015331:Cohort Studies; D003404:Creatinine / Q000652:urine*; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D008297:Male; D012044:Regression Analysis; D015203:Reproducibility of Results; D047851:September 11 Terrorist Attacks; D012907:Smoking / Q000652:urine*; D014481:United States; D014589:Utah
chemical_list: D015415:Biomarkers; D002104:Cadmium; D003404:Creatinine