High sodium intake can lead to hypertension and increase the risk for heart disease and stroke. ^{(1, 2)}. In 2014, U.S. adults between the ages of 20 and 69 consumed sodium at an average of 3,608 mg/day⁽³⁾. The 2020–2025 Dietary Guidelines for Americans⁽⁴⁾ and the Dietary Reference Intakes for Sodium and Potassium⁽⁵⁾ recommend adults consume no more than 2,300 mg/day of sodium for adults each day. It has been estimated that every 1000 mg/day increase from this recommendation increases the risk of cardiovascular disease events by 17%.⁽²⁾ A large proportion of the sodium consumed in the United States comes from processed foods and foods prepared in restaurants and cafeteria settings—sources over which consumers have little control⁽⁶⁾. Accordingly, this gap between recommended intake and actual intake among U.S. adults requires a public health approach that expands beyond a focus on individual behavior change. Public health approaches to sodium reduction should include strategies that focus on reducing the sodium content in prepackaged and pre-prepared foods^{(7, 8)}.

The Sodium Reduction in Communities Program (SRCP) began as a demonstration project in the U.S. in 2010 to address this growing public health concern. As part of the 2016–2021 round of SRCP, the Centers for Disease Control and Prevention (CDC) funded eight recipients, including local and state health departments and a research university, to work with food service organizations in eight settings to increase the availability and purchase of lower-sodium food options, with the goal of reducing sodium intake to within the recommendation of the 2015–2020 Dietary Guidelines for Americans. The program focuses on four distinct sodium strategies: (1) implementation of food service guidelines and nutritional standards that include sodium; (2) introduction of meal and menu item modifications; (3) integration of lower-sodium food procurement practices; and (4) implementation of behavioral economic strategies to promote lower-sodium items (e.g., placement interventions).

Early outcome data suggest that partnering with local food service organizations to provide consumers with lower-sodium options is an effective strategy to lower population-level sodium consumption.⁽⁹⁾ However, little is known about the cost-effectiveness of strategies implemented in SRCP, which is important for public health policy and planning decisions. In this study, we aimed to provide this information by estimating the cost of achieving implementation outcomes and the cost-effectiveness of strategies implemented in SRCP. First, we estimated the cost per unit of improvement in implementation outcomes, such as persons reached, and food items affected by sodium reduction efforts. This approach provides evidence of the cost of achieving implementation objectives. Second, we estimated the long-term cost-effectiveness of SRCP by integrating the estimates of short-term implementation outcomes and costs with a simulation model, the Prevention Intervention Simulation Model (PRISM)^(10–12). These estimates of cost-effectiveness can be used to support decision making about future sodium reduction efforts.

The average total implementation cost of SRCP recipients was $1,264,609, with low variation (standard deviation = $204,819) (Table 4). The most cost-intensive activity for recipients on average was conducting evaluation but implementing sodium reduction interventions was nearly as costly. There was low variation across all cost categories for recipients with all standard deviations being less than half of the mean. Total monthly costs incurred by SRCP food service organizations averaged $4,282 but varied substantially, ranging from $88 to $28,747 (Table 5). Most of this variation was eliminated when considering the cost per person served at the food service organization. After constructing this measure, only one outlier (more than 3 standard deviations above the mean) remained, and the rest of the values were within a consistent range. This organization was implementing major recipe changes. The most cost-intensive activity for food service organizations on average was additional food preparation, but only six of the food service organizations reported conducting this activity, and their costs varied widely ($27 to $7,886). The next most-costly activities were nutritional analysis and recipe development ($1,648) and healthy food promotion ($1,126), both of which were common activities among partners (conducted by 15 and 12 partners, respectively).

Table 6 shows estimates of the cost of implementation achievements at both the recipient and food service organization levels. At the recipient level, cost per person reached averaged $10, and cost per food service organization reached averaged $42,917. Both metrics had moderate variation, with standard deviations near the mean estimates. Median values were $6 and $36,623, respectively. At the food service organization level, monthly cost per item affected by recipe modification or product substitution averaged $22,869, but this average was driven by one outlier ($183,979); the median was only $684. This outlier was an organization that had incurred substantial implementation costs but had not yet impacted many menu items.

Table 7 presents estimates of the potential long-term cost-effectiveness of SRCP through 2025 and 2040. If changes made are sustained through 2025, the activities implemented under SRCP are projected to decrease premature deaths by 0.17% and medical costs by 0.12% and increase QALYs by 0.77% cumulatively over the entire period among the populations targeted by SRCP recipients. When examining the cost-effectiveness of these impacts, the program is cost saving, indicating that cumulative medical cost savings through 2025 are greater than cumulative program costs. If sustained through 2040, the activities implemented under SRCP are projected to decrease deaths by 0.19% and medical costs by 0.14% and increase QALYs by 0.91% cumulatively over the entire period among the populations targeted by SRCP recipients. When examining the cost-effectiveness of these impacts, the program is cost saving, indicating that cumulative medical cost savings through 2040 are greater than cumulative program costs.

Table 8 presents one way sensitivity analysis testing the impact of changes in assumptions on the projected impact on per capita net costs through 2025 and 2040. A 50% reduction in program effectiveness was estimated to reduce the cost savings of the program, but net costs were still negative indicating the program is still projected to be cost saving. After increasing maintenance cost of the program to 50% and 100% of startup implementation cost, the program is still projected to be cost saving, although the amount saved per capita was reduced.

We evaluated the costs and outcomes of the first three years of the 2016–2021 round of SRCP (September 2016 – September 2019). We estimated the costs of achieving program implementation goals and found that at the recipient level, cost per person reached averaged $10, and cost per food service organization reached averaged $42,917. At the food service organization level, monthly cost per item affected by recipe modification or product substitution had a median of $684. We also estimated the cost-effectiveness of SRCP through 2025 and 2040. Results demonstrate that SRCP strategies are projected to be cost saving through 2025 and 2040 if the sodium reduction observed in program performance measures are sustained. The health impacts were not large, but the program costs are projected to be offset by medical cost savings over time. Furthermore, the health impact could be greater if scaled across a larger population (e.g. the population reached by SRCP was 3.9 million and 20% reduced sodium consumption). The simulated reduction in sodium intake represented 6% of the reduction needed to reach the recommended daily intake of 2300 mg⁽⁵⁾. This average population level reduction is in line with the average reduction across studies identified in a recent systematic review.⁽¹⁴⁾ Understanding the cost of public health programs and the long-term impacts are key to include in a larger framework for public health decisions and chronic disease prevention⁽²²⁾. The results highlight how sodium reduction strategies can impact health and healthcare cost over time. Program implementation costs are primarily incurred at the outset, and once changes are in place (e.g., lower-sodium options available), the impact can compound over time with potential cost savings by 2025. However, it is important to note that program costs are born by public health agencies while the medical cost savings accrue to individuals, payers, and health systems.

Previous studies have used simulation models to examine the potential impact of hypothetical changes in sodium intake with no consideration of strategies to achieve the hypothetical changes^(23–26). One study examined hypothetical strategies for achieving sodium reduction in the United States, estimating that a government-led collaboration with food manufacturers to reduce sodium content would increase life-years by 1.3 million and save $32.1 billion in lifetime medical costs and a sodium tax would increase life-years by 840,113 and save $22.4 billion in lifetime medical costs⁽²⁷⁾. However, the assumptions about the efficacy of strategies used in the study are not drawn from practice-based evidence in the United States and implementation costs are not considered. Other studies have simulated the cost-effectiveness of strategies implemented in other countries, such as the United Kingdom and New Zealand, and estimated approaches to be either cost-effective or cost-saving^{(28, 29)}. The results of this study add to the evidence base by demonstrating what a public health intervention can achieve and incorporating implementation costs for a small set of sodium reduction strategies.

Analysis of the cost of achieving implementation outcomes provides insight into the return on program inputs, demonstrating how much was achieved for investments, and assists in planning for other organizations seeking to implement similar sodium reduction strategies. There was moderate variation in the recipient cost per person and food service organization reached, which may be driven by differences in venues that may be more likely to serve more people less frequently (e.g., hospitals) or fewer people more frequently (e.g., congregate meals). This variation is an important consideration for planners seeking to budget sufficiently to achieve program goals in targeted venues.

Results also highlight the important contributions of partner food service organizations. Past studies have assumed that food service organizations would not incur any additional costs to make recipe modifications or product substitutions because it is part of normal reformulation operations⁽²⁷⁾. However, the results of this study provide contradictory evidence, demonstrating that food service organizations do incur costs on a range of activities, including recipe modification, procurement changes, and overall coordination. This finding is important when considering the feasibility of these sodium reduction strategies because food service organizations may be reluctant to partner given the costs. Other studies of SRCP have shown the importance of external and internal factors to generate buy-in for sodium reduction efforts⁽³⁰⁾, which are important for overcoming potential cost concerns. Cost per menu item affected was relatively consistent across food service organizations after accounting for one large outlier that had incurred substantial cost but had yet to achieve any impact, indicating that results may be useful across a range of organizations implementing sodium reduction strategies. Partners from 7 of the 8 venues submitted cost data, but the highest participation rate was from congregate meals and there was not a clear pattern across the other venues. This may impact results if the probability of response was correlated with lower or higher costs.

This study has several limitations. First, we assumed that we are reducing sodium consumption daily in a consistent population, meaning all of the consumers frequenting these food service organizations eat at these venues daily. We tested this assumption in sensitivity analysis where we reduced the effectiveness measure by 50%. In this analysis, the impact was reduced, but the net effect was still cost saving. Simulations were cost saving up to a 75% reduction in the effectiveness input. This assumption allows us to estimate a population-level effect. However, we know that at least some of these food service organizations do not have consistent patrons. Similarly, reach is likely not representative of community populations, and we do not have information on how populations at a higher risk for cardiovascular disease (e.g. those with high blood pressure or other risk factors) were affected. Second, we assume that changes are sustained through 2025 and 2040, which may not be reasonable because organizations might revert to using higher-sodium recipes or products. Third, PRISM uses a nationally representative population to produce estimates of percentage changes in outcomes. The SRCP target population may not reflect this same population mix, which would impact results. implementation and effectiveness measures reported by recipients were not reported by all organizations for all venues, so we assumed that measures of the percentage of people reducing sodium intake and the average sodium content of foods was generalizable to all organizations and venues. Further they are only performance measures and may not represent the causal impact of the program. Fourth, cost data were collected retrospectively and may be subject to recall bias. Fifth, the partner food service organizations that participated in the cost study were a convenience sample, subject to non-response, and our findings may not be generalizable to all SRCP partner food service organizations. Finally, simulation modeling results are limited by the availability and quality of evidence in the literature. PRISM is based on the latest evidence and has been tested and validated extensively but it is subject to these standard model limitations.

By providing evidence of the cost-effectiveness of a public health sodium reduction initiative, this study is an important advance in the literature on the cost-effectiveness of sodium reduction strategies. Community-level nutrition interventions that augment the amounts of micro- and macro-nutrients in foods that people consume without having to change their behavior have been show to play a key role in improving population health (e.g., folic acid fortification of foods⁽³¹⁾). Community-level change is not easy to achieve, but the success can be substantial and takes the onus off consumers who may not be tracking the nutrient content or who may have constrained options. In food fortification examples, success happened after food fortification policies and standards were set by the U.S. Food and Drug Administration. However, similar to SRCP, food fortification started as a voluntary opt-in by food producers. Sodium reduction strategies at the food service organization level provide an opportunity to make changes to the amount of a nutrient the population consumes and can affect real health outcomes.⁽³²⁾ The findings here represent the current state of implementation but if these efforts could be scaled up, the average daily amount of sodium consumed by U.S. adults could be brought closer to the recommended amount in the dietary guidelines. The results of this study demonstrate the long-term cost-effectiveness of SRCP, which can catalyze future work in sodium reduction and promote scale-up to achieve this impact. Furthermore, the results demonstrate the costs of achieving implementation goals that can support effective planning for future programs, ensuring that budgets are sufficient to achieve impact.