Comparing Three Approaches to Salt Intake Assessment Among Lactating Women in Rural Cambodia

Abstract Objectives Monitoring population salt intake is a critical component of implementing salt fortification programs. In Cambodia, salt is being considered as a vehicle for thiamine fortification to prevent infantile beriberi among breastfed infants. However, salt intake among lactating mothers is not known. The gold standard for assessing sodium intake is repeat 24-hr urinary sodium concentrations. This method has logistical barriers, especially in low-resource settings, and other methods have not been trialed in this population. Here we compare three methods of assessing salt intake in lactating Cambodian women: repeat 24-hr urinary sodium concentrations (USC), repeat 12-hr observed weighed intake records (OWIR), and household salt disappearance (HSD). Methods Data from trial: NCT03616288. Salt intake was assessed using the three methods in a subsample of lactating women (n = 104) between 8 and 22 weeks postpartum. Women were asked to collect two 24-hour urine samples within 7 days. Repeat 12-hr OWIR were collected from women. Household salt disappearance was recorded fortnightly, and was divided by the number of household members to estimate individual intakes. Descriptive household salt use was also recorded. Differences in estimated salt intake from each method were compared using a Kruskal-Wallis test. Results Mean (95%CI) estimated salt intakes from repeat 24-hr USC, repeat 12-hr OWIR, and HSD were: 9.0 (8.3, 9.8) g/day, 9.1 (7.9, 10.3) g/day, and 10.9 (9.8, 11.9) g/day, respectively. Estimated intakes from HSD were significantly higher than both 24-hr USC (p = 0.009) and 12-hr OWIR (p = 0.002). Estimated intakes from 24-hr USC and 12-hr OWIR were not statistically different (p = 0.6). Salt was being used for purposes other than consumption, such as cleaning fish and vegetables, in 26% of fortnightly visits. Conclusions Repeat 24-hr USC and 12-hr OWIR are both acceptable and logistically feasible methods of salt intake assessment among lactating women in rural Cambodia. While HSD is a less resource-intensive approach, this method over-estimated salt intake. Salt being used for purposes other than consumption may contribute to over-estimation using this method. Funding Sources Bill & Melinda Gates Foundation, New York Academy of Sciences, Canadian Institutes of Health Research, Research Nova Scotia.