Association between 24-hour urine sodium and potassium excretion and diet quality in six-year-old children: a cross sectional study

BACKGROUND Limited data is available on sodium (Na) and potassium (K) intake in young children estimated by 24 hour (24h) excretion in urine. The aim was to assess 24h urinary excretion of Na and K in six-year-old children and its relationship with diet quality. METHODS The study population was a subsample of a national dietary survey, including six-year-old children living in the greater Reykjavik area (n=76). Three day weighed food records were used to estimate diet quality. Diet quality was defined as adherence to the Icelandic food based dietary guidelines. Na and K excretion was analyzed from 24h urine collections. PABA check was used to validate completeness of urine collections. The associations between Na and K excretion and diet quality were estimated by linear regression, adjusting for gender and energy intake. RESULTS Valid urine collections and diet registrations were provided by 58 children. Na and K excretion was, mean (SD), 1.64 (0.54) g Na/24h (approx. 4.1 g salt/24h) and 1.22 (0.43) g K/24h. In covariate adjusted models Na excretion decreased by 0.16 g Na/24h (95% CI: 0.31, 0.06) per 1-unit increase in diet quality score (score range: 1-4) while K excretion was increased by 0.18 g K/24h (95% CI: 0.06, 0.29). CONCLUSIONS Na intake, estimated by 24h urinary excretion was on average higher than recommended. Increased diet quality was associated with lower Na excretion and higher K excretion in six-year-old children.