Table 1 Health economic modelling studies of population-level dietary salt reduction interventions in high-income countries which use the health metric of QALYs or DALYs and have cost implications (ordered by publication date^a)

26 European countries^b, Murray et al 2003 [52]

(i) Cooperation between government and the food industry for a stepwise decrease in salt content of processed foods and for labelling; (ii) Legislation to decrease sodium content in processed foods and appropriate labelling (a combined package); (iii) Health education focusing on body mass index and cholesterol concentrations; (iv) A combined package of (ii) and (iii).

0.7-1.3 million DALYs averted per year (in European countries group). Very cost-effective at US$14-37 per DALY averted (DR = 3 %). Legislation reported to be more cost-effective than voluntary agreements.

This study did not consider cost-savings from preventing CVD. It was reliant on the relatively simplistic WHO Choice methodology for costing intervention programmes.

US, Palar & Sturm 2009 [53]

Reducing average population sodium intake to 1200-2300 mg/day [d].

Large annual QALY gains (312,000) and large annual savings in health costs (US$18 billion).

QALYs were also valued as part of a societal perspective. No specific intervention or intervention costs.

US, Smith-Spangler et al 2010 [54]

(i) Collaboration with industry to reduce sodium by 9.5 %, and (ii) a sodium tax to reduce sodium by 6 %.

Both interventions achieved large QALY gains (2.1 million and 1.3 million respectively over the cohort’s lifetime). Cost-savings at $US32.1 and 22.4 billion respectively.

A high quality study but the cost of implementing the tax intervention was not considered.

US, Bibbins-Domingo et al 2010 [18]

A regulatory intervention to reduce the level of salt intake by 3 g/d.

Large annual QALY gains (194,000 to 392,000) and annual cost-savings at $US10 to 24 billion. Salt reduction was more cost-effective than treating hypertension with medications. The anticipated relative benefits in blacks were greater than those for non-blacks across all age and sex groups.

A high quality study but no specific intervention or intervention costs detailed. This is only one of two studies in this table to consider ethnic inequalities.

Australia, Cobiac et al 2010 [55]

Voluntary and mandatory reduction of salt content in breads, margarine, and cereals; dietary advice; and labelling programme.

Both salt content interventions were cost-saving (e.g., $A3.3 billion for the mandatory one over the cohorts lifetime) but health gain was much greater for the mandatory vs voluntary intervention (e.g., 110,000 vs 5300 lifetime DALYs averted). The labelling programme was cost-effective but not the dietary advice.

Included a useful comparison between a voluntary and mandatory intervention. Used WHO Choice methods rather than more country-specific intervention costing data.

England & Wales, Barton et al 2011 [56]

Legislative means (unspecified) to reduce salt intake by 3 g/d

Any salt-reduction intervention costing up to £40 million a year was estimated to be cost-saving. For a 3 g/d reduction over 10 years the total QALY gain was 131,000.

No specific intervention was modelled. See also comments in a review [57].

Finland, Martikainen et al 2011 [17]

A population-wide 1 g/d salt reduction (by unspecified means).

Large QALY gains (26,100 by the year 2030). Cost-savings were 150–225 million Euros by 2030 (but when combined with the saturated fat reduction intervention).

Also considered reductions in productivity losses. No specific intervention was modelled. See also comments in a review [57].

Australia, Cobiac et al 2012 [58]

Mandatory reduction of salt content in breads, margarine, and cereals; and Community Heart Health Programme (CHHP).

Large number of DALYs averted per year (80,000) for the mandatory intervention (vs 3000 in the CHHP) and cost-saving. (See also a similar study listed above by these authors).

This study allowed for a comparison of the mandatory salt reduction with various CVD treatment interventions (the former being more cost-effective).

England, Dodhia et al 2012 [59]

Included: (i) reductions of salt leading to 2 mmHg and (ii) 5 mmHg reductions in blood pressure; (iii) reduced intake down to 6 g/d via assumed food industry agreement; (iv) advice for DASH-sodium diets.

Large number of DALYs averted for (i) to (iv) in the 200,000 to 900,000 range (DR = 3.5 %). Salt reduction in the population was always reported to be cost-saving except for dietary advice in some age-groups (but here it was still cost-effective). The maximum saving for an intervention was £1.9 billion (over 10y).

High quality study which allowed comparisons with CVD treatment interventions.

New Zealand, Nghiem et al 2015 [5]

Eight interventions (mix of mandatory and voluntary interventions – see Table 5 for findings combined with the results of this particular study).

All interventions (except dietary counselling) were cost-saving. The largest gain was from a “sinking lid” intervention (211,000 QALYs over the cohort’s lifetime; $US0.7 billion in savings). The interventions were estimated to produce relatively greater health gain for indigenous people (Māori).

The study had some limitations including around price elasticity data (for the salt tax) and the hypothetical nature of some interventions (e.g., sinking lid). See the Discussion where we compare these results with the current analysis.