title: Evaluation of spot urine as an alternative to 24h urine collection for determination of biomarkers of exposure to cigarette smoke in adult smokers.
abstract: OBJECTIVE
  Exposure to cigarette smoke in adult smokers (SM) can be determined by measuring urinary excretion of selected smoke constituents or metabolites. Complete 24h urine collections are difficult to achieve in ambulatory clinical studies; therefore spot urine (SU) might be a useful alternative. The objective of this study was to evaluate the optimum time for SU collections, and to predict 24h urine biomarker excretion from SU collections.
  
  
  METHODS
  SU samples were collected at three time points (early morning, post-lunch and evening) along with 24h collections in 37 healthy adult smokers. Nicotine and its five metabolites (nicotine equivalents, NE), metabolites of NNK (NNAL), pyrene (1-OHP), acrolein (HPMA), benzene (S-PMA) and butadiene (MHBMA) were measured in 24h and SU samples. Correlation and agreement between creatinine-adjusted SU and 24h urine collections were determined from the Pearson product-moment correlation, Bland-Altman and Lin's concordance correlation analyses. A random effect regression model was used to calculate the 24h biomarker excretion from SU collections.
  
  
  RESULTS
  There were no significant differences (p>0.05) between the three SU collections for the selected biomarkers of exposure except for 3-HPMA, which showed a diurnal variation. Good correlation and statistical agreements were observed for creatinine-adjusted SU (all three time points) and 24h for most of the selected biomarkers. 24h biomarker excretion could be estimated for most of the biomarkers based on the regression model, with the early morning SU collections giving the best results for tobacco specific biomarkers NE (R(2)=0.66) and NNAL (R(2)=0.6).
  
  
  CONCLUSIONS
  SU is a useful alternative to 24h urine collections for most of the selected biomarkers of exposure to cigarette smoke. The early morning SU appears to be the most feasible and practical option as an alternative to 24h collections.
authors.affiliation: Altria Client Services Inc., Center for Research and Technology, Richmond, VA 23219, USA. mohamadi.Sarkar@altria.com
authors.forename: Mohamadi
authors.initials: M
authors.lastname: Sarkar
authors.forename: Raheema
authors.initials: R
authors.lastname: Muhammad-Kah
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Liang
authors.forename: Sunil
authors.initials: S
authors.lastname: Kapur
authors.forename: Shixia
authors.initials: S
authors.lastname: Feng
authors.forename: Hans
authors.initials: H
authors.lastname: Roethig
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D012907:Smoking / Q000652:urine*; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D059349:Urine Specimen Collection / Q000379:methods*; D055815:Young Adult
chemical_list: D015415:Biomarkers