Estimated sodium intake and premature ventricular complexes: data from the population-based Swedish CArdioPulmonary bioImage Study.

Background: Premature ventricular complexes (PVCs) predict coronary heart disease, heart failure, atrial fibrillation and death, all of which are also related to sodium intake. We studied estimated sodium intake and PVC frequency in the randomly selected population-based Swedish CArdioPulmonary bioImage Study cohort.

Methods: In our cross-sectional study, we included 5636 individuals with 24-hour ECG registration and fasting morning urine sampling. Sodium intake was estimated using the Kawasaki formula, and the association between sodium intake and PVC frequency was modelled using multivariable negative binomial regression, adjusted for age, sex, body mass index, level of education, height, physical activity and smoking status, across prespecified strata of sodium intake: <2 g/day, 2-2.99 g/day, 3-3.99 g/day (reference category), 4-4.99 g/day and ≥5 g/day.

Results: The median age was 57.6 years, and 51.9% were female. The median daily PVC count was 8 (IQR 3-41); 5.9% had ≥500 PVCs/24 hours. The mean estimated sodium intake was 3.3 g/day. There was a U-shaped association between sodium intake and PVCs. Compared with the reference of 3-3.99 g/day (28% of participants), sodium intakes <2 g/day (15% of participants) and ≥5 g/day (10% of participants) were associated with 26% (95% CI 6% to 49%) and 52% (95% CI 26% to 84%, p<0.01) increases in PVC frequency, respectively, but intakes of 2-2.99 g/day and 4-4.99 g/day were not (5% (95% CI -8% to 20%) and 4% (95% CI -11% to 22%) increase, respectively).

Conclusion: There was a U-shaped association between sodium intake and PVC frequency, with both low and high sodium intake associated with higher PVC frequency.