Noushin Mohammadifard1, Hamidreza Marateb2, Marjan Mansourian3, Alireza Khosravi4,5, Zahra Abdollahi6, Norman Rc Campbell7, Jacqui Webster8, Kristina Petersen9, Nizal Sarrafzadegan1,10. 1. Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, 3rd Moshtagh St., 81583-88994 Isfahan, Iran. 2. Biomedical Engineering Department, Engineering Faculty, University of Isfahan, Hezar Jerib St., 81746-73441 Isfahan, Iran. 3. Epidemiology and Biostatistics Department, Health School, Isfahan University of Medical Sciences, Isfahan, Iran. 4. Hypertension Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran. 5. Interventional Cardiology Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran. 6. Nutrition Department, The Ministry of Health and Medical Education, Tehran, Iran. 7. Department of Medicine, Physiology and Pharmacology and Community Health Sciences, O'Brien Institute for Public Health and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada. 8. Office of the Chief Scientist, The George Institute for Global Health, The University of New South Wales, Sydney, New South Wales, Australia. 9. Food Policy Division, The George Institute for Global Health, The University of New South Wales, Sydney, New South Wales, Australia. 10. School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
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.
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.
Authors: Lesley F Tinker; Ying Huang; Karen C Johnson; Laura D Carbone; Linda Snetselaar; Linda Van Horn; JoAnn E Manson; Simin Liu; Yasmin Mossavar-Rahmani; Ross L Prentice; Johanna W Lampe; Marian L Neuhouser Journal: Curr Dev Nutr Date: 2021-10-12