Dietary sodium and potassium intake and risk of diabetes in the Million Veteran Program

Studies show an association between elevated blood pressure, obesity, and insulin resistance with a higher risk of developing diabetes. As sodium is closely linked to elevated blood pressure and hypertension, and potassium is a counterbalancing nutrient to sodium, this study examines the association between intake of sodium, potassium, and sodium: potassium (Na:K) ratio and the incidence of diabetes.

Retrospective data analysis of dietary intake measured by a validated food frequency questionnaire in a prospective cohort of veterans participating in the Million Veteran Program (MVP) between 2011 and 2020, who were free of diabetes at baseline.

The main outcome is clinically diagnosed diabetes defined by phenotyping algorithms applied to electronic health records.

In this study of 198,049 veterans (mean age: 63.8 ± 13.1 years, 89 % male), 7260 were diagnosed with diabetes over a mean follow-up of 4.3 years. The mean sodium intake was 1218 mg/day. A higher sodium intake was associated with an 11 % higher rate of developing diabetes (hazard ratio, HR) comparing extreme quintiles: 1.11, 95 % CI: 1.03-1.20). The average daily potassium intake was 2589 mg and the highest quintile of potassium intake was associated with a 13 % lower rate of diabetes (HR: 0.87, 95 % CI: 0.81, 0.94) compared to the lowest quintile of potassium. Highest quintile of Na:K ratio was associated with a 21 % higher rate for diabetes (HR: 1.21, 95% CI: 1.12, 1.30). The pattern of associations between Na:K ratio and diabetes closely followed the pattern of dietary sodium intake and diabetes associations.

A higher sodium intake and a higher Na:K ratio were associated with a higher risk of diabetes in this large cohort of veterans. These findings may be applied in future work to identify personalized lifestyle and dietary supports to prevent and treat T2DM.