Study Reveals J-Shaped Link Between Sodium Intake and Atrial Fibrillation Risk: Targeting High Sodium Diets for Prevention

In this cohort study of sodium intake and AF risk, the researchers found a J-shaped association between sodium intake and AF risk in patients with CVD or diabetes.

Sodium intakes exceeding 6 grams per day were linked to a 10% increase in risk for every additional gram of sodium consumed, the researchers reported, suggesting that lowering sodium intake for atrial fibrillation prevention is best targeted at individuals who consume high sodium diets exceeding 6 g per day.

Several prospective cohort studies have revealed a J-shaped association of urinary sodium excretion with cardiovascular events and mortality. Linda S. Johnson, Department of Clinical Sciences in Malmö, Lund University in Lund, Sweden, and colleagues aimed to study the association between sodium intake and incident atrial fibrillation.

This cohort study involved participants from the ONTARGET and the TRANSCEND. These multicenter, randomized clinical trials compared the effects of daily doses of 10 mg ramipril, 80 mg telmisartan, or their combination (ONTARGET), as well as 80 mg telmisartan versus placebo (TRANSCEND), on outcomes such as cardiovascular death, myocardial infarction, stroke, and hospitalization for heart failure. ONTARGET and TRANSCEND included 31,546 participants with vascular disease or high-risk diabetes, excluding those without a urine sample for sodium measurement, missing key data, a history of atrial fibrillation, or AF detected within the first year of enrollment. Analyses were conducted from July 2023 to May 2024.

The primary outcome was incident AF. Multivariable adjusted Cox regression and cubic splines modeled the association between estimated sodium intake and incident AF.

The study revealed the following findings:

• 27, 391 participants (mean age, 66.3 years; 70.5% males) were included. The mean estimated sodium intake was 4.8 g/d.
• During a mean follow-up of 4.6 years, 5.7% of participants had incident AF.
• After multivariable adjustment, a J-shaped association between sodium intake and AF risk was observed.
• Sodium intake of 8 g/d or greater (3% of participants) was associated with incident AF (hazard ratio, 1.32) compared with sodium intake of 4 to 5.99 g/d.
• Cubic splines showed that sodium intake greater than 6 g/d (19% of participants) was associated with a 10% increased AF risk per additional 1-g/d sodium intake (hazard ratio, 1.10), but with no further lowering of AF risk at lower levels of sodium intake.

"In the cohort study examining sodium intake and the risk of incident atrial fibrillation (AF), we found a J-shaped relationship between sodium consumption and the incidence of AF," the reach team concluded. "These data suggest that decreasing sodium intake for AF prevention is best targeted at individuals who consume high-sodium diets."

Reference:

Johnson LS, Mente A, Joseph P, et al. Sodium Intake and Incident Atrial Fibrillation in Individuals With Vascular Disease. JAMA Netw Open. 2024;7(7):e2421589. doi:10.1001/jamanetworkopen.2024.21589