Accepted for/Published in: JMIR Public Health and Surveillance
Date Submitted: Nov 24, 2025
Open Peer Review Period: Nov 24, 2025 - Jan 19, 2026
Date Accepted: Mar 31, 2026
(closed for review but you can still tweet)
Urinary Sodium Excretion and the Risk of Prevalent Anemia: A Nationwide Population-Based Cross-Sectional Study from the KNHANES
ABSTRACT
Background:
While excessive dietary sodium intake is an established risk factor for cardiovascular and renal complications, its potential association with anemia remains unexplored.
Objective:
We hypothesized that, based on the benefit of sodium-glucose cotransporter 2 inhibitors on anemia correction through alterations in renal tubular metabolism and oxygen homeostasis, elevated urinary sodium excretion may increase the risk of prevalent anemia.
Methods:
This nationwide cross-sectional study analyzed 54,802 adults from the Korea National Health and Nutrition Examination Survey (2014-2023). Participants were stratified by spot urine sodium-to-creatinine ratio (Na+/Cr) quartiles (Q1, Q2, Q3 and Q4). Anemia was defined as hemoglobin < 13 g/dL for men and < 12 g/dL for women, respectively.
Results:
Anemia prevalence increased progressively across spot urine Na+/Cr quartiles (Q1: 5.5%, Q2: 7.1%, Q3: 8.8%, Q4: 12.9%). Multivariable logistic regression demonstrated that the participants in the highest quartile demonstrated 43% higher odds of anemia compared to the lowest quartile (adjusted odds ratio (OR) 1.429, 95% CI 1.269-1.610, P <0.001). Each one-unit log increase in spot urine Na+/Cr conferred 67% elevated odds of anemia (adjusted OR 1.674, 95% CI 1.452-1.930, P < 0.001). Sensitivity analyses using tertiles, quintiles, estimated 24-hour sodium excretion, and restriction to preserved kidney function consistently confirmed these associations.
Conclusions:
Higher urinary sodium excretion exhibits a robust, graded association with increased anemia prevalence in the general population. These findings suggest dietary sodium restriction may provide additional benefits beyond cardiovascular protection.
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