Can methods based on spot urine samples be used to estimate average population 24 h sodium excretion? Results from the Isfahan Salt Study

Noushin Mohammadifard, Hamidreza Marateb, Marjan Mansourian, Alireza Khosravi, Zahra Abdollahi, Norman R.C. Campbell, Jacqui Webster, Kristina Petersen, Nizal Sarrafzadegan

Research output: Contribution to journalArticle

Abstract

Objective: To assess agreement between established methods of estimating salt intake from spot urine collections and 24 h urinary Na (24hUNa) and then to develop a valid formula that can be used in the Iranian population to estimate salt intake from spot urine samples.Design: A validation study. Three spot urine samples were collected (fasting second-void morning; afternoon; evening) on the same day as a 24 h urine collection. We estimated 24hUNa from spot specimens using the Kawasaki, Tanaka and INTERSALT equations. Two new formulas were developed, the Iran formula 1 (Iran 1) and Iran formula 2 (Iran 2), based on our population characteristics.Setting: Iranian adults recruited in 2014-2015.Participants: Healthy volunteer adults aged ≥18 years.Results: With all three spot urine specimens, predicted population 24hUNa was underestimated based on the INTERSALT equation (-469 to -708 mg/d; all P < 0·05) and conversely overestimation occurred with the Kawasaki equation (926 to 1080 mg/d; all P < 0·01). The Tanaka equation produced comparable estimates to measured 24hUNa (-151 to 86 mg/d; all P > 0·49). The newly derived formulas, Iran 1 and Iran 2, showed less mean bias than the established equations (Iran 1: 43 to 80 mg/d, all P > 0·55; Iran 2: 22 to 90 mg/d, all P > 0·50).Conclusions: In this Iranian sample, the Tanaka equation and newly derived formulas produced group-level estimates comparable to measured 24hUNa. The newly developed formulas showed less mean bias than established equations; however, they need to be tested for generalization in a larger sample.

Original languageEnglish (US)
Pages (from-to)202-213
Number of pages12
JournalPublic Health Nutrition
Volume23
Issue number2
DOIs
StatePublished - Feb 1 2020

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health

Fingerprint Dive into the research topics of 'Can methods based on spot urine samples be used to estimate average population 24 h sodium excretion? Results from the Isfahan Salt Study'. Together they form a unique fingerprint.

  • Cite this

    Mohammadifard, N., Marateb, H., Mansourian, M., Khosravi, A., Abdollahi, Z., Campbell, N. R. C., Webster, J., Petersen, K., & Sarrafzadegan, N. (2020). Can methods based on spot urine samples be used to estimate average population 24 h sodium excretion? Results from the Isfahan Salt Study. Public Health Nutrition, 23(2), 202-213. https://doi.org/10.1017/S136898001900257X