Analysis of 24-hour urine samples from a large sample of US adults provides important baseline data on estimated sodium and potassium intake, reports a study in The Journal of the American Medical Association.
The cross-sectional study included 24-hour urine collections from 827 men and women aged 20 to 69 years. The subjects were drawn from the examination component of the National Health and Nutrition Examination Survey (NHANES) in 2014. The researchers estimated 24-hour urinary sodium and potassium excretion and their molar ratios.
Nearly two-thirds of the study population were white; Hispanic, black, and Asian racial/ethnic groups were represented as well. Hypertension was present in 43.5% of individuals, while 10.0% said they had been diagnosed with diabetes.
Mean 24-hour sodium excretion was 3608 mg, with a median of 3320 mg. Mean sodium excretion was higher in men than women, 4205 versus 3039 mg; and somewhat higher in subjects aged 20 to 44 compared to older ages, 3699 versus 3507 mg.
The mean value for 24-hour urine potassium excretion was 2155 mg overall, 2399 mg in men, and 1922 mg in women. Mean potassium excretion was 2155 mg in subjects aged 20 to 44 and 2343 mg in those aged 45 to 69. Overall mean sodium-to-potassium molar ratio was 3.17, with a median of 2.87.
Twenty-four-hour urine collection is recommended for more accurate estimation of US sodium intake. Based on previous studies suggesting that about 90% of consumed sodium is excreted in urine, the cross-sectional data suggest a mean sodium intake of approximately 4000 mg/d in US adults. Mean potassium intake appears to be below currently recommended levels. The authors discuss the cross-sectional findings in light of previous studies and suggest their data will provide a useful benchmark for future research [Cogswell ME, et al. Estimated 24-hour urinary sodium and potassium excretion in US adults. JAMA 2018; 319:1209−1220].