Systematic Review on the Impact of Salt-Reduction Initiatives by Socioeconomic Position to Address Health Inequalities in Adult Populations.

Context: International evidence shows that individuals from low socioeconomic positions (SEPs) consume a greater amount of salt than those from higher SEPs. This health inequality reflects a disproportionate effect of salt-reduction initiatives, and explains a higher prevalence of cardiovascular disease among the most vulnerable populations. Assessing this impact can help tailor implementation strategies in the future for the benefit of the whole population.

Objective: The aim was to systematically review the literature and assess the impact of salt-reduction initiatives on health and behavioral outcomes of adults by SEP.

Data sources: The search strategy was conducted in 6 databases (CINAHL, Scopus, Embase, MEDLINE, PubMed, and Web of Science) using the terms sodium or salt, social class, policy, intervention or campaign. Peer-reviewed articles assessing salt-reduction interventions in adults reporting dietary or behavioral changes on salt consumption measurements by SEP were considered for inclusion. Articles in which salt intake data were not reported by SEP were excluded.

Data extraction: Two reviewers collected data independently using a predesigned electronic form. The AXIS and RoB 2 tools were used for critical appraisal.

Data analysis: Eight studies containing data from 111 548 adults were interpreted according to study design following a narrative synthesis approach.

Results: Salt-reduction initiatives are effective at reducing the intake of salt and sodium in adults. When reporting the impact of these initiatives, research outcomes are generally not evaluated by SEP, representing a question yet to be explored.

Conclusion: A small number of articles that focused on the impact of salt-reduction interventions reported salt consumption measurements by SEP, indicating a critical gap in research. The limited evidence suggests potentially greater health benefits to be gained from the implementation of population-wide initiatives in adults of low SEP.

Systematic review registration: PROSPERO registration no. CRD42021238055.