Urinary sodium-to-potassium ratio: it may be SMART, but is it easy?

Protocol for a novel sodium and blood pressure reduction intervention targeting online grocery shoppers with hypertension - the SaltSwitch Online Grocery Shopping randomized trial

BACKGROUND

High dietary sodium intake is a leading cause of hypertension. A major source of dietary sodium is salt added to processed food products available in retail food environments. The fast-growing online grocery shopping setting provides new opportunities for salt reduction interventions that support consumers in choosing healthier options.

METHODS

The SaltSwitch Online Grocery Shopping randomized controlled trial is investigating the feasibility, acceptability, and effectiveness of a novel intervention for lowering salt consumption and blood pressure amongst people with hypertension who shop for groceries online. The intervention is based on a bespoke web browser extension that interfaces with a major retailer's online store to highlight and interpret product sodium content and suggest similar but lower-sodium alternatives. The primary outcome of interest is change in mean systolic blood pressure between individuals randomized (1:1) to the intervention and control (usual online shopping) arms at 12 weeks. Secondary outcomes are diastolic blood pressure, spot urinary sodium and sodium:potassium ratio, sodium purchases, and dietary intake. Intervention implementation and lessons for future uptake will be assessed using a mixed methods process evaluation. Participants with hypertension who shop online for groceries and exhibit high sodium purchasing behavior are being recruited across Australia. A target sample size of 1,966 provides 80% power (2-sided alpha = 0.05) to detect a 2 mm Hg difference in systolic blood pressure between groups, assuming a 15 mm Hg standard deviation, after allowing for a 10% dropout rate.

DISCUSSION

This trial will provide evidence on an innovative intervention to potentially reduce salt intake and blood pressure in people with hypertension. The intervention caters to individual preferences by encouraging sustainable switches to similar but lower-salt products. If effective, the intervention will be readily scalable at low cost by interfacing with existing online retail environments.

Micronutrient Adequacy in Preschool Children Attending Family Child Care Homes

Limited data is available on the micronutrient intake and adequacy in preschool children enrolled in family child care homes (FCCH). The goal of this paper is to describe the micronutrient adequacy relative to age-specific recommendations of preschool-aged children (aged 2-5 years) attending FCCH in Rhode Island (RI). Dietary data among younger preschoolers (aged 2-3 years), n = 245) and older preschoolers (aged 4-5 years), n = 121) in 118 RI FCCH (N = 366 children) were analyzed. Nutrient adequacy was assessed as the amount of nutrient per 1000 kcal of the diet that would meet the Institute of Medicine nutrient requirements (critical nutrient density), and it was compared to the observed nutrient densities of the children. The sodium:potassium ratio was also calculated. For most micronutrients, the observed density met or exceeded the recommendation, meaning the children's intake was adequate. However, a high proportion of children had nutrient densities under the recommendation for vitamins D, E, K, and potassium (86.1%, 89.1%, 70.8%, and 99.2% of children, respectively). The mean vitamin B12, potassium, and zinc densities were statistically higher in younger vs. older preschoolers (p < 0.05 for all). Low densities in calcium and vitamins K and B5 were more frequent in older children vs. younger children (p < 0.05). In addition, older preschoolers had a higher sodium:potassium ratio than younger children (p < 0.05). The micronutrient intake density was adequate for most nutrients. However, intake of some nutrients was of concern. Further attention to training and compliance in FCCH may improve the diet quality of those cared for in these settings.

Dietary sodium to potassium ratio and the incidence of hypertension and cardiovascular disease: A population-based longitudinal study

OBJECTIVE

There is an interaction between dietary sodium/potassium intake in the pathogenesis of hypertension (HTN) and cardiovascular disease (CVD). The aim of this study was to investigate the association of dietary sodium to potassium (Na/K) ratio and the risk of HTN and CVD in a general population of Iranian adults.

METHODS

In this prospective cohort study, adults men and women with complete baseline data were selected from among participants of the Tehran Lipid and Glucose Study and were followed up for 6.3 years for incidence of HTN and CVD outcomes. Dietary sodium and potassium were assessed using a valid and reliable 168-item food frequency questionnaire. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between dietary sodium, potassium and their ratio and risk of outcomes.

RESULTS

During the study follow-up, 291 (15.1%) and 79 (5.0%) new cases of HTN and CVD were identified, respectively. No significant association was observed between usual intakes of sodium, potassium and dietary Na/K ratio with the incidence of HTN. There was no significant association between dietary intakes of sodium and potassium per se and the risk of CVD, whereas when dietary sodium to potassium ratio was considered as exposure in the fully-adjusted Cox regression model, and participants in the highest compared to lowest tertile had a significantly increased risk of CVD (HR = 2.19, 95% CI = 1.16-4.14).

CONCLUSIONS

Our findings suggest that high dietary Na/K ratio could contribute to increased risk of CVD events.