Estimating Usual Sodium Intake and Sodium-to-Potassium Molar Ratios From Urine Excretion Among Canadian Adults: An Analysis of the Canadian Health Measures Survey

Abstract

\n \n \n High dietary sodium is now well established to be a major risk factor for hypertension, cardiovascular disease and mortality. Monitoring population sodium intakes is critical for evaluating progress towards Health Canada s dietary salt reduction targets. Given that approximately 90% of ingested sodium is excreted in the urine, accurate estimations of average daily urinary sodium is critical for determining population sodium intake. However, until recently, nationally representative surveys from Canada have only collected a single “spot” (casual) urine sample which are prone to bias due to large day-to-day variation amongst individuals. The aim of this study was to estimate average population sodium intake using the latest version of the Canadian Heath Measures Survey, Cycle 5 (2016–2017) which, for the first time includes 2 non-consecutive days of spot urine samples from a representative sample of the Canadian population.\n \n \n \n The INTERSALT equations, validated for western populations, was used to estimate 24hr intakes of sodium amongst adults ≥19 years of age, excluding pregnant women (n\xa0=\xa03032). Individual sodium-to-potassium molar ratios (Na: K) were also calculated, given their importance in predicting hypertension risk. The second day of spot urines was used to control for within-person variation in both sodium excretion and NA: K molar ratios, using the National Cancer Institute method for estimating usual dietary intake, adjusting for respondents’ fasting status.\n \n \n \n Mean sodium excretion was 3142\xa0±\xa030\xa0mg/day and 3154\xa0±\xa030\xa0mg/dayin men and women, respectively. In both men and women only 14% of participants consumed less than the recommended 2300\xa0mg of sodium/day. The Na: K was approximately 1.4 in both men and women with only 15–20%, at or below, an optimal Na: K of 1.\n \n \n \n This is the first study from Canada to estimate sodium and NA: K at the population level, using two days of spot urine samples, providing robust baseline data for continued monitoring. Our findings reveal a need for ongoing efforts to reduce population sodium and improve potassium intakes in order to reduce cardiovascular risk.\n \n \n \n Canadian Institutes of Health Research.\n