Dietary sodium to potassium ratio is an independent predictor of cardiovascular events: a longitudinal follow-up study

BACKGROUND: The current prospective cohort study aimed to explore the potential associations between dietary sodium (Na), potassium (K), and sodium-to-potassium (Na-to-K) ratio with an incidence risk of cardiovascular disease (CVD) among Iranian adults. METHODS: The participants of the Tehran Lipid and Glucose Study (men and women aged 30–84 years, n = 2050), free of CVD at baseline (2006–2008) were included. Dietary intakes were assessed using a validated food frequency questionnaire (FFQ), and incident CVD (i.e., coronary heart disease, stroke, and CVD mortality) were documented up to March 2018. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence interval (CI) regarding the association between dietary Na, K, and Na-to-K ratio with CVD events. RESULTS: During a median follow-up of 10.6 years, 10.14% of participants experienced CVD outcomes. A 41% increased risk of CVD in relation to each increase in 1000 mg/d of Na intake. In the fully-adjusted model, higher Na intake (> 4143 versus < 3049 mg/d) was significantly related to the increased risk of CVD (HR = 1.99, 95% CI = 1.06–3.74). Independent of the well-known risk factors, a 56% reduced risk of CVD was observed in the participants with a higher dietary K intake (HR = 0.44, 95% CI = 0.20–0.94). A Higher Na-to-K ratio was associated with an increased risk of CVD (HR = 1.99, 95% CI = 1.13–3.52). CONCLUSION: Our study showed that the Na-to-K ratio might independently predict future risk of CVD events in adults. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-023-15618-7.