Vol.:(0123456789) 1 3 European Journal of Nutrition (2020) 59:3149–3161 https://doi.org/10.1007/s00394-019-02153-8 ORIGINAL CONTRIBUTION Is salt intake reduction a universal intervention for both normotensive and hypertensive people: a case from Iran STEPS survey 2016 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 4,10 Received: 7 March 2019 / Accepted: 20 November 2019 / Published online: 4 December 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 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 efect of salt intake on BP. Results After adjusting for covariates, there was a signifcant 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 signifcant 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 signifcantly increased SBP in both hypertensive and normoten- sive people, though the magnitude of this increase was greater in hypertensive people as compared with normotensive people. Keywords Salt · Blood pressure · Hypertensive · Normotensive · Iran Introduction Excess salt intake is associated with the development of sev- eral non-communicable diseases, including cardiovascular diseases (CVDs), the leading cause of death [1] and stomach cancer, the third leading cause of cancer death worldwide [2, 3]. Diet high in sodium was responsible for 20.32% hyper- tensive heart disease death, 13.47% stroke death, 11.58% ischemic heart diseases death, and 9.83% stomach cancer death worldwide [4]. Excess salt intake exerts its detrimental efect directly or through increasing the blood pressure (BP) [3]. Hypertension (HTN) is one of the main risk factors for CVDs. It has been estimated that HTN is responsible for more than half of deaths from stroke and coronary heart dis- ease in adults worldwide [4]. The role of excess salt intake in increasing BP has been confrmed in the previous epide- miological and clinical studies [5]. However, debates exist over the relationship of salt intake and its efect on BP in the general population [6, 7]. These debates focus on fnd- ings achieved from some clinical trials with the controlled circumstance that it might not be simply generalized to gen- eral populations. In this setting, a high-quality observational study has revealed only a weak association between sodium intake and BP in the general population [8]. * Farshad Farzadfar f-farzadfar@tums.ac.ir Extended author information available on the last page of the article