Authors

Ali Gholami 1 2 3, Shahabeddin Rezaei 4 5, Leila Moosavi Jahromi 6, Hamid Reza Baradaran 3 7, Ali Ghanbari 4 8, Shirin Djalalinia 4 9, Nazila Rezaei 4, Shohreh Naderimagham 4, Mitra Modirian 4, Negar Mahmoudi 4, Zohreh Mahmoudi 4 10, Mohammad Javad Hajipour 4 11, Ahmad Kousha 12, Siamak Mirab Samiee 13, Farshad Farzadfar 14 15

Affiliations

1Noncommunicable Diseases Research Center, Neyshabur University of Medical Sciences, Neyshabur, Iran.

2Department of Epidemiology and Biostatistics, School of Public Health, Neyshabur University of Medical Sciences, Neyshabur, Iran.

3Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.

4Non-Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.

5Students’ Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.

6Health Management and Economics Research Center, Iran University of Medical Sciences, Tehran, Iran.

7Ageing Clinical and Experimental Research Team, Institute of Applied Health Sciences, School of Medicine, Medical Sciences and Nutrition University of Aberdeen, Aberdeen, UK.

8Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

9Deputy of Research and Technology, Ministry of Health and Medical Education, Tehran, Iran.

10Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.

11Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran.

12Department of Health Education and Promotion, Faculty of Health Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.

13Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran.

14Non-Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. f-farzadfar@tums.ac.ir.

15Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. f-farzadfar@tums.ac.ir.

Abstract

Purpose: There is a direct association between salt intake and blood pressure (BP), one of the main risk factors for CVDs. However, yet there has been a debate that how strong is this association in people with and without hypertension. This study was conducted to evaluate the magnitude of the association between salt intake and BP in hypertensive and normotensive population among a nationally representative population.

Methods: The study was conducted on a nationally representative sample of 18,635 Iranian adults aged 25 years and older who participated in the STEPS survey 2016 and provided urine sample. Salt intake was estimated through spot urine sample and Tanaka equation. Multiple linear regression model in survey data analysis was used to assess the independent effect of salt intake on BP.

Results: After adjusting for covariates, there was a significant association between salt intake and SBP in hypertensive (p < 0.001) and normotensive people (p < 0.001). In hypertensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.37 mmHg and 0.07 mmHg, respectively. Whereas in normotensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.26 mmHg and 0.05 mmHg, respectively. Moreover, there was a significant trend toward an increase of SBP across salt intake quartiles in both hypertensive (p < 0.001) and normotensive people (p = 0.002), though the slope was steeper in hypertensive than in normotensive people. Conclusions: The present study demonstrated that salt intake significantly increased SBP in both hypertensive and normotensive people, though the magnitude of this increase was greater in hypertensive people as compared with normotensive people.

Keywords: Blood pressure; Hypertensive; Iran; Normotensive; Salt.