title: A critical appraisal of goiter assessment and the ratio of urinary iodine to creatinine for evaluating iodine status.
abstract: Iodine status can be evaluated by goiter assessment and measurement of urinary iodine concentration in either 24-h urine collections or in casual samples. It is often impossible to make 24-h collections. Therefore, iodine concentration in casual samples is often expressed in terms of urinary creatinine, assuming creatinine excretion to be constant between and within individuals. In this study large inter- and intraindividual variations were observed in the creatinine content of casual samples ranging from 0.6 to 9.87 mmol/L. Further, the urinary iodine-creatinine ratio correlated significantly with the creatinine concentration; Spearman's rank-order correlation coefficient, rs = 0.39 (P < 0.001). If creatinine is a suitable index to correct for variations in iodine excretion, no correlation would be expected. We conclude that the iodine-creatinine ratio in casual urine samples is an unsuitable indicator for evaluating iodine status in areas where large inter- and intraindividual variations in urinary creatinine excretion exist.
authors.affiliation: Department of Human Nutrition, Wageningen Agricultural University, The Netherlands.
authors.forename: C A
authors.initials: CA
authors.lastname: Furnée
authors.forename: F
authors.initials: F
authors.lastname: van der Haar
authors.forename: C E
authors.initials: CE
authors.lastname: West
authors.forename: J G
authors.initials: JG
authors.lastname: Hautvast
mesh_terms: D002648:Child; D003404:Creatinine / Q000652:urine*; D005260:Female; D006042:Goiter / Q000175:diagnosis*; D006801:Humans; D007455:Iodine / Q000172:deficiency / Q000652:urine*; D008297:Male
chemical_list: D007455:Iodine; D003404:Creatinine