JMIR Publications

ABSTRACT

Background:

Nowadays mHealth technology have been increasingly used for treatment and prevention at all levels of healthcare. Associating this technology with the promotion of healthy salt consumption - both cost-effective and cost-saving public health strategies - can reduce this risk factor that contributes expressively to the increase of non-communicable diseases worldwide.

Objective:

To assess the usability and the efficacy of a mobile app intervention - ‘Sal na Medida App’-, on the promotion of a healthy salt intake among adults, based on the Behaviour Change Wheel framework. And, to investigate if Intention, Self-efficacy and Habit variables mediated the effect of intervention on salt intake.

Methods:

An experimental, randomized and longitudinal study that evaluated the intervention effect with assessments at baseline, post intervention (1 month), and at follow-up (2 months). Sociodemographic and clinical data were collected from participants recruited at primary health care centers. Behavior of salt intake and per capita salt consumption were the primary outcomes. Psychosocial variables of Intention, Self-efficacy and Habit were assessed as possible mediators. Usability was evaluated after 1 month and 2 months of using the App.

Results:

Eighty-six participants were randomized in Intervention Group - IG (43) or Control Group - CG (43). The majority of participants were female (IG = 83.7%; CG = 86%). Usability of App intervention scored 77.8 points (on a scale of 0 to 100) among IG participants. There was a significant reduction in salt intake in IG according to the variables of per capita salt and behavior of salt intake. Furthermore, at the end of the follow-up, individuals in IG were 67% more likely to have a lower salt intake than those in the CG. The regression analysis showed an increase of Intention and the perception of Self-efficacy, and a more pronounced reduction in the Habit of using more than 3g of salt/day in preparing meals in IG when compared to CG. Habit and Self-efficacy were identified as mediators of the intervention's effect.

Conclusions:

The theory-based mobile app intervention for reducing salt intake has shown promise both in terms of usability and efficacy among adults. Conducting further studies to assess its potential for implementation on a larger scale would be valuable for determining its real-world impact and feasibility. Clinical Trial: The Brazilian Clinical Trials Registry (ReBEC) RBR-4s8qyyq; https://ensaiosclinicos.gov.br/rg/RBR-4s8qyyq.