Salt Reduction Intervention in Families Investigating Metabolic, Behavioral and Health Effects of Targeted Intake Reductions: Study Protocol for a Four Months Three-Armed, Randomized, Controlled "Real-Life" Trial

Abstract

Reductions in salt intake have the potential to markedly improve population health at low cost. Real life interventions that explore the feasibility and health effects of a gradual salt reduction lasting at least four weeks are required. The randomized controlled SalT Reduction InterVEntion (STRIVE) trial was developed to investigate the metabolic, behavioral and health effects of four months of consuming gradually salt reduced bread alone or in combination with dietary counselling. This paper describes the rationale and methods of STRIVE. Aiming at 120 healthy families, participants were recruited in February 2018 from the Danish Capital Region and randomly allocated into: (A) Salt reduced bread; (B) Salt reduced bread and dietary counseling; (C) Standard bread. Participants were examined before the intervention and at four months follow-up. Primary outcome is change in salt intake measured by 24 h urine. Secondary outcomes are change in urine measures of potassium and sodium/ potassium ratio, blood pressure, plasma lipids, the renin-angiotensin system, the sympathetic nervous response, dietary intake as well as salt taste sensitivity and preferences. The results will qualify mechanisms affected during a gradual reduction in salt intake in compliance with the current public health recommendations.

Keywords: cardiovascular consequences; gradual salt reduction; randomized controlled trial; sodium potassium ratio; statistical analysis plan.

Figure 1

Trial flow diagram. Participants were recruited as families, screened for eligibility and informed about the trial. After informed consent the baseline examination was completed followed by allocation to trial group. Then dietary record and urine was collected for one week, while consuming own bread before intervention start. Depending on when collection of dietary data and 24 h urine ended the run-in period with standard bread varied from one to two weeks. Participants consumed intervention bread the following 13–16 weeks, depending on the date of the follow-up visit. The follow-up visit included one week of 7-day dietary record + three 24 h urine collections while consuming intervention bread. Hereafter, the intervention ended.