A method to monitor the national salt reduction efforts in Sri Lanka and status of salt, potassium and iodine intake in an adult Sri Lankan community

Abstract

Sri Lanka has initiated a salt reduction strategy in 2019 to reduce salt consumption to 8\xa0g/day by 2025. Recent national level salt consumption data is lacking. Although 24-hour urine (24-hU) collection is the gold standard to assess salt intake, an alternative easy option for monitoring population salt consumption is needed. The objective of this study was to assess the current salt, potassium, and iodine intake of adults based on 24-hU and identify the best prediction equation to estimate these nutrients from spot urine (SU) samples. A cross-sectional study was conducted among adults between 25-64 years of age. 24-hU and SU samples were collected. Several equations were used to estimate salt, potassium, and iodine from SU samples. The agreement between the estimates from 24-hU and SU was assessed through Bland-Altman plots and intraclass correlation coefficients. Among 852 adults recruited, 629 provided complete 24-hU. Measured 24-hU salt, potassium and iodine were: 11.4 (IQR 7.7–17.1) g, 2.1 (95 % CI 1.9–2.2) g and 209.8 (IQR 130.9–310.9) µg, respectively. Comparison of estimates from 24-hU and SU samples showed, Kawasaki equation provided the closest estimate for salt intake [median bias -0.2(-0.4–5.2) g; ICC 0.39; misclassification 13.6 %]; the equations used to estimate potassium intake performed poorly; while the Zimmerman equation provided the closest estimate for iodine [median bias -13.2 (-129.8–92.7) µg; ICC 0.33; misclassification 37.2 %]. The adult population studied in Sri Lanka had high salt, low potassium, and optimum iodine intakes compared to the WHO recommendations. Collection of 24-hU in a subset of SU samples will be important to monitor the salt reduction efforts.