Sodium intake of a city population in Korea estimated by 24-h urine collection method

Accurate estimation of sodium intake by a precise and reproducible method is crucial in sodium intake reduction policy. This study tested the feasibility of 24-h urine (24HU) collection method and estimated sodium intake of a major city population from a representative adult sample.

A representative population (aged 20-65 years) was selected by list-assisted random-digit dialing method from a city with a population of one million. Sodium and potassium intakes (24HUNa and 24HUK, respectively) were measured with 24HU collection.

Of those 496 individuals recruited, 24HU samples from 368 participants were determined to be properly collected and analyzed. The weighted mean of 24HUNa was 166.4 ± 68.1 mmol per day, much lower than 208.2 mmol of 24HUNa measured in Pusan (Korea; 1988 INTERSALT). The 24HUNa was highest in population aged 40-49 years, with a decrease after 50 years. Men had higher 24HUNa than women (182.0 ± 77.6 vs 151.4 ± 55.0 mmol per day). The sodium intake is higher than that found in survey conducted in the United Kingdom/Scotland and Finland, similar to that of Spain and lower than that of Portugal, Slovenia and Turkey. In contrast to 24HUNa, 24HUK increased continuously as age increased.

This study enables us to compare sodium intake with the results of other surveys even from other countries, and reinforce the recommended introduction of the 24HU collection method in Korea. Sodium intake of the studied population was higher than the World Health Organization recommendation, suggesting the needs for further efforts to reduce sodium intake.