App based education programme to reduce salt intake (AppSalt) in schoolchildren and their families in China: parallel, cluster randomised controlled trial

Abstract

Objective To determine whether a smartphone application based education programme can lower salt intake in schoolchildren and their families. Design Parallel, cluster randomised controlled trial, with schools randomly assigned to either intervention or control group (1:1). Setting 54 primary schools from three provinces in northern, central, and southern China, from 15 September 2018 to 27 December 2019. Participants 592 children (308 (52.0%) boys; mean age 8.58 (standard deviation 0.41) years) in grade 3 of primary school (about 11 children per school) and 1184 adult family members (551 (46.5%) men; mean age 45.80 (12.87) years). Intervention Children in the intervention group were taught, with support of the app, about salt reduction and assigned homework to encourage their families to participate in activities to reduce salt consumption. Main outcome measures Primary outcome was the difference in salt intake change (measured by 24 hour urinary sodium excretion) at 12 month follow-up, between the intervention and control groups. Results After baseline assessment, 297 children and 594 adult family members (from 27 schools) were allocated to the intervention group, and 295 children and 590 adult family members (from 27 schools) were allocated to the control group. During the trial, 27 (4.6%) children and 112 (9.5%) adults were lost to follow-up, owing to children having moved to another school or adults unable to attend follow-up assessments. The remaining 287 children and 546 adults (from 27 schools) in the intervention group and 278 children and 526 adults (from 27 schools) in the control group completed the 12 month follow-up assessment. Mean salt intake at baseline was 5.5 g/day (standard deviation 1.9) in children and 10.0 g/day (3.5) in adults in the intervention group, and 5.6 g/day (2.1) in children and 10.0 g/day (3.6) in adults in the control group. During the study, salt intake of the children increased in both intervention and control groups but to a lesser extent in the intervention group (mean effect of intervention after adjusting for confounding factors −0.25 g/day, 95% confidence interval −0.61 to 0.12, P=0.18). In adults, salt intake decreased in both intervention and control groups but to a greater extent in the intervention group (mean effect −0.82 g/day, −1.24 to −0.40, P<0.001). The mean effect on systolic blood pressure was −0.76 mm Hg (−2.37 to 0.86, P=0.36) in children and −1.64 mm Hg (−3.01 to −0.27, P=0.02) in adults. Conclusions The app based education programme delivered through primary school, using a child-to-parent approach, was effective in lowering salt intake and systolic blood pressure in adults, but the effects were not significant in children. Although this novel approach could potentially be scaled up to larger populations, the programme needs further strengthening to reduce salt intake across the whole population, including schoolchildren. Trial registration Chinese Clinical Trial Registry ChiCTR1800017553.

Effect of salt reduction interventions in lowering blood pressure: A comprehensive systematic review and meta-analysis of controlled clinical trials

“…Furthermore, in all the studies, BP measurement was performed by health professionals or trained personnel, with the exception of three studies that relied solely upon self-reported measures [ 34 , 35 , 47 ]. The included studies employed different types of intervention strategies that were categorized into four domains; 21 trials with nutritional education [ 21 , 28 , 31 , 38 , 40 – 42 , 46 , 49 , 50 , 52 , 55 , 56 , 59 – 61 ], 17 used salt substitutes [ 23 , 25 – 27 , 29 – 31 , 33 , 43 – 45 , 54 , 58 ], ten used self-help materials [ 34 – 37 , 39 , 47 , 48 , 51 , 53 , 57 ], and two trials employed food reformulation [ 22 , 24 ]. The control groups of all trials received usual care or no intervention.…”

Process Evaluation of an Application-Based Salt Reduction Intervention in School Children and Their Families (AppSalt) in China: A Mixed-Methods Study

“…The control group was not evaluated as they continued with their usual health education and did not receive any extra intervention activities or materials from the program. The detailed demograhic characteristics of the participants in the AppSalt program could be found in our previous publication ( 12 ).…”

“…The primary outcome for assessing the effectiveness of the trial is measured by the difference between the intervention and control groups in the change of salt intake measured by 24-h urinary sodium from baseline to the end of the trial ( 11 ). The effectiveness evaluation found that the salt intake in intervened adults decreased by 0.82 g/day ( 12 ).…”

Can children play a role in reducing families’ salt intake?

“…Children’s homework was to get the whole family involved in the salt reduction activities following the guide in the app. The study involving 54 primary schools in northern, central, and southern China and demonstrates that this app-based education programme is feasible and effective in lowering the families’ salt intake over one year 6. Importantly, the programme was accepted and perceived as an engaging education tool by most participants and teachers.…”