Estimated 24-hour urinary sodium and potassium excretion in US Adults

IMPORTANCE In 2010, the Institute of Medicine (now the National Academy of Medicine) recommended collecting 24-hour urine to estimate US sodium intake because previous studies indicated 90% of sodium consumed was excreted in urine. OBJECTIVE To estimate mean population sodium intake and describe urinary potassium excretion among US adults. DESIGN, SETTING, AND PARTICIPANTS In a nationally representative cross-sectional survey of the US noninstitutionalized population, 827 of 1103 (75%) randomly selected, nonpregnant participants aged 20 to 69 years in the examination component of the National Health and Nutrition Examination Survey (NHANES) collected at least one 24-hour urine specimen in 2014. The overall survey response rate for the 24-hour urine collection was approximately 50% (75%[24-hour urine component response rate] × 66%[examination component response rate]). EXPOSURES 24-hour collection of urine. MAIN OUTCOMES AND MEASURES Mean 24-hour urinary sodium and potassium excretion. Weighted national estimates of demographic and health characteristics and mean electrolyte excretion accounting for the complex survey design, selection probabilities, and nonresponse. RESULTS The study sample (n = 827) represented a population of whom 48.8% were men; 63.7%were non-Hispanic white, 15.8% Hispanic, 11.9% non-Hispanic black, and 5.6% non-Hispanic Asian; 43.5%had hypertension (according to 2017 hypertension guidelines); and 10.0%reported a diagnosis of diabetes. Overall mean 24-hour urinary sodium excretion was 3608mg (95%CI, 3414-3803). The overall median was 3320mg (interquartile range, 2308-4524). In secondary analyses by sex, mean sodium excretion was 4205mg (95%CI, 3959-4452) in men (n = 421) and 3039mg (95%CI, 2844-3234) in women (n = 406). By age group, mean sodium excretion was 3699mg (95%CI, 3449-3949) in adults aged 20 to 44 years (n = 432) and 3507mg (95%CI, 3266-3748) in adults aged 45 to 69 years (n = 395). Overall mean 24-hour urinary potassium excretion was 2155mg (95%CI, 2030-2280); by sex, 2399mg (95%CI, 2253-2545) in men and 1922mg (95%CI, 1757-2086) in women; and by age, 1986mg (95%CI, 1878-2094) in adults aged 20 to 44 years and 2343mg (95%CI, 2151-2534) in adults aged 45 to 69 years. CONCLUSIONS AND RELEVANCE In cross-sectional data from a 2014 sample of US adults, estimated mean sodium intake was 3608mg per day. The findings provide a benchmark for future studies.