By Dr Jonathan Shurlock
Edited by Dr Ahmed El-Medany
Previous evidence has suggested an association between increased salt intake and carotid artery atherosclerosis, with less data available for the relationship with coronary atherosclerosis. Dr Jonas Wuopio and colleagues have sought to further explore this relationship through a sub-analysis of the Swedish CArdioPulmonary bioImage Study (SCAPIS). SCAPIS is an open-access, population-based cohort study, with the aim of studying both cardiovascular and chronic obstructive pulmonary disease. The study has recruited 30,154 Swedish participants aged from 50 to 64 years old. Participants undergo detailed imaging and functional analysis of their cardiovascular and pulmonary systems.
Dr Wuopio’s study identified a subset of 10,778 SCAPIS participants, with an average age of 58 (52% Female). Participants underwent computed tomography coronary angiography (CTCA, n = 9623) and coronary artery calcium scoring (CACS, n = 10,289). These individuals also underwent carotid ultrasound. In order to identify salt intake the authors used the Kawasaki formula for estimation of 24 hour sodium excretion (est24hNa).
Ordered logistic regression was used in an attempt to calculate the odds ratio for both coronary and carotid atherosclerosis, per stepwise increase in est24hNa (1000mg increments). Increasing salt intake was associated with an increase in both coronary artery stenosis (OR: 1.17, P < 0.001, CI: 1.13–1.20) and carotid artery plaque [OR: 1.09, P < 0.001, confidence interval (CI): 1.06–1.12]. There was also an association with increased salt intake and higher CAC (OR: 1.16, P < 0.001, CI: 1.12–1.19)
The authors suggest that their study demonstrated a linear association between salt intake and atherosclerosis in both the coronary and carotid arteries and suggest that these effects are present even prior to the onset of hypertension. One strength of the study includes the use of 24-hour urinary sodium excretion as a reliable measure of salt intake. However, the limits of the Kawasaki formula have been previously explored; and other limitations including the unknown generalisability to other populations, residual confounding, and the cross-sectional design of the study, should be considered when interpreting these findings.
Read the full study here: https://academic.oup.com/ehjopen/article/3/2/oead024/7093096