This study was conducted to investigate the effects of sodium-potassium ratio on insulin resistance and sensitivity in Korean adults.

Subjects were 3,722 adults (1,632 men and 2,090 women) aged 40–69 years participating in the Korean genome and epidemiology study_Ansan and Ansung study. Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HoMA-IR) and fasting insulin, and insulin sensitivity was assessed by using the quantitative insulin sensitivity check index (QUICKI). The 24-h urinary sodium and potassium excretion were estimated from spot urinary samples using the Tanaka formula. The generalized linear model was applied to determine the association between urinary sodium-potassium ratio and insulin resistance.

HoMA-IR ( P -value = 0.029, P -trend = 0.008) and fasting insulin ( P -value = 0.017, P -trend = 0.005) levels were positively associated with 24-h estimated urinary sodium-potassium ratio in the multivariable model. QUICKI was inversely associated with 24-h estimated urinary sodium-potassium ratio in all models ( P -value = 0.0002, P -trend < 0.0001 in the multivariate model).

The present study suggests that high sodium-potassium ratio is related to high insulin resistance and low insulin sensitivity. Decreasing sodium intake and increasing potassium intake are important for maintaining insulin sensitivity. Further studies are needed to confirm these findings in longitudinal studies.