title: A longitudinal study of urinary creatinine and creatinine clearance in normal subjects. Race, sex, and age differences.
abstract: The purpose of this study was to examine the variability of 24-hour urinary and serum creatinine levels and creatinine clearance in normal subjects and to develop nomograms for assessing the adequacy of 24-hour urine collections. The data were from a longitudinal research program examining biochemical, hormonal, and hemodynamic parameters in normal subjects. Bloods and 24-hour urine specimens were collected at yearly intervals from 144 people over 9 years, and from an additional 110 over 4 years. The subjects were originally distributed equally by sex, race (black, white), blood pressure (three groups within the normal range), and age (three groups). Men had 33% higher urine creatinines per weight than females (P less than 0.001). Because they only had 8% higher creatinine clearance per weight they also exhibited 21% higher serum creatinine. Blacks had 5% higher urine creatinine per weight than whites, perhaps reflecting greater muscle mass, but their serum creatinines were not different from those of whites, reflecting a 5% higher creatinine clearance by weight than whites (P less than 0.01). Interestingly, older black men (age greater than 60 years) had 12% lower urine creatinine/weight than younger black men (P less than 0.001). They also had 13% lower creatinine clearance by weight, resulting in no net difference in serum creatinine. The intraindividual variability in urine creatinine excretion averaged 15% and did not differ between blacks and whites and men and women. The within individual variability in serum creatinine and creatinine clearance averaged 14 and 20%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Cardiovascular Center, New York Hospital-Cornell University Medical College, NY 10021.
authors.forename: G D
authors.initials: GD
authors.lastname: James
authors.forename: J E
authors.initials: JE
authors.lastname: Sealey
authors.forename: M
authors.initials: M
authors.lastname: Alderman
authors.forename: S
authors.initials: S
authors.lastname: Ljungman
authors.forename: F B
authors.initials: FB
authors.lastname: Mueller
authors.forename: M S
authors.initials: MS
authors.lastname: Pecker
authors.forename: J H
authors.initials: JH
authors.lastname: Laragh
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000378:metabolism*; D003404:Creatinine / Q000097:blood / Q000378:metabolism / Q000652:urine*; D006801:Humans; D007206:Individuality; D008137:Longitudinal Studies; D008875:Middle Aged; D044469:Racial Groups; D012016:Reference Values; D012727:Sex Characteristics; D013997:Time Factors
chemical_list: D003404:Creatinine