24 Hour Urinary Sodium Excretion Survey: The PURE Sodium Sentinel Sites Study (24USE)

Project Background

Sodium intake is related to the development of hypertension a frequent major risk factor for cardiovascular disease, and to other morbidities. A population preventative approach to reducing salt intake should be based upon sound data on sodium levels from urinary excretion in a large sample. Such a study does not exist in Canada but has been conducted successfully in the UK and Finland.

Study Design and Purpose

Using a cross-sectional design, 400 consecutive participants coming for their annual visit at each PURE study site (200 rural and 200 urban) will collect their 240hour urine sample. During the 240hour collection, 50 consecutive participants at each site will take a urine sample before the evening meal (PDU) and a first morning urine (FMU) at the end of the 24 hour collection. Fifteen to 45 days after the 24-hour collection, 100 participants from each site will repeat 24-hour collection to estimate the measurement variability. Participants aged 37 to 64 years will also take 3 PABA tablets with meals as a marker for verifying completeness of the urine collection, according to standard HPLC lab methods. The collected 24-hour urines will also be used to gauge iodine nutritional status in Canada. 

Significance of the Research

Sodium intake is reported to be a key modifiable determinant of hypertension, which is a principal risk factor for CVD, the leading cause of death, disability, and health spending in Canada. Consequently, population-wide reduction of dietary sodium consumption has been recommended by major scientific organizations as an important population-health approach to prevent and reduce the impact of hypertension. Despite the importance of monitoring sodium intake in populations, historical and current data on sodium consumption in Canada is very limited. Therefore a priority for population health research is to measure the current level of sodium and potassium intake in the general population within Canada, and to determine the optimum range of sodium within the population at large, based on a precise and objective method to measure sodium intake.