title: Restricted intraindividual urinary iodine concentration variability in nonfasting subjects.
abstract: OBJECTIVE
  Individual urinary iodine concentration (UIC) reflects iodine intake over a short time prior to sampling. Since eating habits are relatively constant in single subjects, UIC should be relatively constant in a given individual. The aim of our study was to verify this hypothesis by assessing UIC in repeated single urine samples from a group of healthy subjects.
  
  
  METHODS
  A prospective sequential investigation was performed in 131 volunteer health workers or students recruited in our University hospital.
  
  
  METHODS
  Single urine samples were taken in a nonfasting state, between 0900 and 1100 hours. Group 1 was composed by 131 subjects who collected one urine sample. Group 2 was composed by 11 subjects of the group 1, who collected multiple repeated urine samples (as a whole 158 urine samples, mean 14 samples each). UIC mean+/-s.d., median and coefficient of variation (CV%) was measured in both groups.
  
  
  RESULTS
  Interindividual UIC variation was wide, UIC ranging from 21 to 382 microg/l, mean 136+/-84 microg/l, median 124 microg/l, CV 62%. Also in the 11 subjects repeatedly sampling there were considerable differences among individual UIC average levels (ranging from 37+/-15 to 221+/-91 microg/l). However, in this second group, the intraindividual variation was considerably restricted (CV% 36).
  
  
  CONCLUSIONS
  The present study shows that in a nonfasting state in mid-morning UIC is more stable from day to day in a single subject, depending on his eating habits, than in various subjects. Thus, a single urine sample even in nonfasting state may give some rough information about the individual's iodine status.
authors.affiliation: Endocrinology Unit, Department of Medical and Surgical Sciences, University of Padua, Padua, Italy. benedetto.busnardo@unipd.it
authors.forename: B
authors.initials: B
authors.lastname: Busnardo
authors.forename: D
authors.initials: D
authors.lastname: Nacamulli
authors.forename: L
authors.initials: L
authors.lastname: Zambonin
authors.forename: C
authors.initials: C
authors.lastname: Mian
authors.forename: M
authors.initials: M
authors.lastname: Piccolo
authors.forename: M E
authors.initials: ME
authors.lastname: Girelli
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D006042:Goiter / Q000175:diagnosis / Q000652:urine; D006304:Health Status; D006801:Humans; D007455:Iodine / Q000172:deficiency / Q000652:urine*; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D007455:Iodine