Reduction of population sodium intake has been identified as a key initiative for reduction of Non-Communicable Disease. Monitoring of population sodium intake must accompany public health initiatives aimed at sodium reduction. A number of different methods for estimating dietary sodium intake are currently in use. Dietary assessment is time consuming and often under-estimates intake due to under-reporting and difficulties quantifying sodium concentration in recipes, and discretionary salt. Twenty-four hour urinary collection (widely considered to be the most accurate method) is also burdensome and is limited by under-collection and lack of suitable methodology to accurately identify incomplete samples. Spot urine sampling has recently been identified as a convenient and affordable alternative, but remains highly controversial as a means of monitoring population intake. Studies suggest that while spot urinary sodium is a poor predictor of 24-h excretion in individuals, it may provide population estimates adequate for monitoring. Further research is needed into the accuracy and suitability of spot urine collection in different populations as a means of monitoring sodium intake.

Background: Estimating equations based on spot urine samples have been identified as a possible alternative approach to 24-h urine collections for determining mean population salt intake. This review compares estimates of mean population salt intake based upon spot and 24-h urine samples. Methods: We systematically searched for all studies that reported estimates of daily salt intake based upon both spot and 24-h urine samples for the same population. The associations between the two were quantified and compared overall and in subsets of studies. Results: A total of 538 records were identified, 108 were assessed as full text and 29 were included. The included studies involved 10 414 participants from 34 countries and made 71 comparisons available for the primary analysis. Overall average population salt intake estimated from 24-h urine samples was 9.3 g/day compared with 9.0 g/day estimated from the spot urine samples. Estimates based upon spot urine samples had excellent sensitivity (97%) and specificity (100%) at classifying mean population salt intake as above or below the World Health Organization maximum target of 5 g/day. Compared with the 24-h samples, estimates based upon spot urine overestimated intake at lower levels of consumption and underestimated intake at higher levels of consumption. Conclusions: Estimates of mean population salt intake based upon spot urine samples can provide countries with a good indication of mean population salt intake and whether action on salt consumption is required.

The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) is a coalition of intentional and national health and scientific organizations formed because of concerns low‐quality research methods were creating controversy regarding dietary salt reduction. One of the main sources of controversy is believed related to errors in estimating sodium intake with urine studies. The recommendations and positions in this manuscript were generated following a series of systematic reviews and analyses by experts in hypertension, nutrition, statistics, and dietary sodium. To assess the population's current 24‐hour dietary sodium ingestion, single complete 24‐hour urine samples, collected over a series of days from a representative population sample, were recommended. To accurately estimate usual dietary sodium at the individual level, at least 3 non‐consecutive complete 24‐hour urine collections obtained over a series of days that reflect the usual short‐term variations in dietary pattern were recommended. Multiple 24‐hour urine collections over several years were recommended to estimate an individual's usual long‐term sodium intake. The role of single spot or short duration timed urine collections in assessing population average sodium intake requires more research. Single or multiple spot or short duration timed urine collections are not recommended for assessing an individual's sodium intake especially in relationship to health outcomes. The recommendations should be applied by scientific review committees, granting agencies, editors and journal reviewers, investigators, policymakers, and those developing and creating dietary sodium recommendations. Low‐quality research on dietary sodium/salt should not be funded, conducted, or published.

The Global Burden of Disease (GBD) 2010 study estimated national salt intake for 187 countries based on data available up to 2010. The purpose of this review was to identify studies that have measured salt intake in a nationally representative population using the 24‐hour urine collection method since 2010, with a view to updating evidence on population salt intake globally. Studies published from January 2011 to September 2018 were searched for from MEDLINE, Scopus, and Embase databases using relevant terms. Studies that provided nationally representative estimates of salt intake among the healthy adult population based on the 24‐hour urine collection were included. Measured salt intake was extracted and compared with the GBD estimates. Of the 115 identified studies assessed for eligibility, 13 studies were included: Four studies were from Europe, and one each from the United States, Canada, Benin, India, Samoa, Fiji, Barbados, Australia, and New Zealand. Mean daily salt intake ranged from 6.75 g/d in Barbados to 10.66 g/d in Portugal. Measured mean population salt intake in Italy, England, Canada, and Barbados was lower, and in Fiji, Samoa, and Benin was higher, in recent surveys compared to the GBD 2010 estimates. Despite global targets to reduce population salt intake, only 13 countries have published nationally representative salt intake data since the GBD 2010 study. In all countries, salt intake levels remain higher than the World Health Organization's recommendation, highlighting the need for additional global efforts to lower salt intake and monitor salt reduction strategies.

Subscription and open access journals from SAGE Publishing, the world's leading independent academic publisher.