Association of Adding Salt to Foods and Potassium Intake with Incident Atrial Fibrillation in the UK Biobank Study

Background: High sodium and low potassium consumption are related to hypertension and cardiovascular disease. We aimed to determine the relationship between the frequency of salt addition and potassium consumption with the risk of new-onset atrial fibrillation (AF). Methods: Our study used the UK Biobank cohort, which included over 500,000 individuals enrolled from the United Kingdom between 2006 and 2010. This study involved 416,868 participants who filled out the dietary recall regarding the frequency of salt addition. Results: During follow-up, 19,164 (4.6%) developed AF. The incidence of new-onset AF was increased based on the frequency of salt addition (never/rarely 3.83; always 4.72 per 1000 person-years). Compared with the group that never/rarely added salt, those adding salt always were at significantly higher risk of incident AF after adjusting for multiple variables (hazard ratio (HR) 1.15; 95% confidence interval (CI) 1.06–1.24), and additional adjustment of dietary and total energy consumption (HR 1.37; 95% CI 1.08–1.73). In the subgroup analysis, the risk of AF incident according to the frequency of salt addition significantly increased in low urine potassium levels compared to high (p for interaction = 0.046). In the subgroup analysis for AF patients, higher salt addition frequency was related to increased all-cause mortality. Conclusions: Our study demonstrated that adding salt to foods more frequently increases the risk of incident AF, even after adjusting for dietary and total energy consumption. In the high urine potassium group, the impact of high sodium consumption on incident AF was attenuated.