New Anthropometry-Based Formulae to Predict 24 h Sodium Excretion from Spot Urine.

Area of Science:

• Cardiovascular Health
• Nutritional Epidemiology
• Clinical Chemistry

Background:

• Cardiovascular diseases are a leading global cause of death.
• Hypertension and high sodium intake are major contributing factors.
• Accurate sodium intake estimation is vital, but traditional 24-hour urine collection is impractical.

Purpose of the Study:

• Develop and validate population-specific formulas for estimating 24-hour urinary sodium excretion from spot urine samples.
• Utilize data from a representative Swiss adult population.
• Improve upon existing spot urine-based prediction formulae.

Main Methods:

• Developed models incorporating age, sex, and anthropometry-based, population-specific, estimated urinary creatinine excretion values.
• Included models with and without urea and potassium.
• Compared model performance against established formulae (INTERSALT, Kawasaki, Tanaka) and timed nocturnal urine collection.

Main Results:

• Models based on first morning urine showed improved accuracy and lower bias compared to existing equations.
• Swiss anthropometric model achieved AUCs of 0.85 (with urea: 0.86).
• Models demonstrated consistent performance across clinically relevant sodium intake thresholds, suitable for clinical settings.

Conclusions:

• New simple and reliable formulae offer a practical tool for estimating sodium intake from first morning urine spot samples.
• These formulae are promising for adult European populations and clinical applications.
• Timed nocturnal urine collection further enhances accuracy.