title: Validation of spot urine in predicting 24-h sodium excretion at the individual level.
abstract: Background:Evidence for the effect of dietary sodium intake on the risk of cardiovascular disease has been controversial. One of the main explanations for the conflicting results lies in the great variability associated with measurement methods for sodium intake. Spot urine collection is a convenient method commonly used for sodium estimation, but its validity for predicting 24-h urinary sodium excretion at the individual level has not been well evaluated among the general population.Objective:The aim of this study was to evaluate the validity of the Kawasaki, the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT), and the Tanaka formulas in predicting 24-h urinary sodium excretion by using spot urine samples in Chinese adults.Design:We analyzed the relative and absolute differences and misclassification at the individual level from 3 commonly used methods for estimating sodium intake among 141 Chinese community residents.Results:The mean measured 24-h sodium excretion was 220.8 mmol/d. The median (95% CIs) differences between measured sodium and those estimated from the Kawasaki, INTERSALT, and Tanaka methods were 6.4 mmol/d (-17.5, 36.8 mmol/d), -67.3 mmol/d (-96.5, -46.9 mmol/d), and -42.9 mmol/d (-59.1, -24.8 mmol/d), respectively. The proportions of relative differences >40% with the Kawasaki, INTERSALT, and Tanaka methods were 31.2%, 41.1%, and 22.0%, respectively; and the absolute difference for the 3 methods was >51.3 mmol/d (3 g salt) in approximately half of the participants. The misclassification rate was 63.1% for the Kawasaki method, 78.7% for the INTERSALT method, and 66.0% for the Tanaka method at the individual level.Conclusion:The results from our study do not support the use of spot urine to estimate 24-h urinary sodium excretion at the individual level because of its poor performance with respect to misclassification. This trial was registered at www.chictr.org.cn as ChiCTR-IOR-16010278.
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.|Division of Preventive Oncology, National Center for Tumor Disease, German Cancer Research Center, Heidelberg, Germany.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Jiangxi Center for Disease Control and Prevention, Nanchang, China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Fu
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; and.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Jiang
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; and.
authors.forename: Ya-Min
authors.initials: YM
authors.lastname: Bai
authors.affiliation: Dexing Center for Disease Control and Prevention, Dexing, China.
authors.forename: Zi-Hua
authors.initials: ZH
authors.lastname: Zhang
authors.affiliation: Dexing Center for Disease Control and Prevention, Dexing, China.
authors.forename: Xiao-He
authors.initials: XH
authors.lastname: Hu
authors.affiliation: Dexing Center for Disease Control and Prevention, Dexing, China.
authors.forename: Hong-Wu
authors.initials: HW
authors.lastname: Lian
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; and zhaolch@163.com zxyang@ilsichina.org.
authors.forename: Zheng-Xiong
authors.initials: ZX
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; zhaolch@163.com zxyang@ilsichina.org.
authors.forename: Lian-Cheng
authors.initials: LC
authors.lastname: Zhao
mesh_terms: D000328:Adult; D044466:Asian People; D001794:Blood Pressure; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012964:Sodium / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000652:urine*; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000652:urine*; D012982:Sodium, Dietary / Q000493:pharmacokinetics / Q000652:urine
chemical_list: D017673:Sodium Chloride, Dietary; D012982:Sodium, Dietary; D012964:Sodium
keywords: 24-hour urine; formula; sodium intake; spot urine; validation