Note: This post (and the underlying report) was updated in October 2023 after additional research and analysis.

Summary:

• We find that advocacy for top sodium control policies to control hypertension to be highly-cost effective (~36,620 DALYs per USD 100,000, which is at least 10x as cost-effective as giving to a GiveWell top charity).
• Beyond raw cost-effectiveness estimates (which are highly uncertain), the cause looks highly promising, given the high quality of evidence underlying the theory of change.
• Reinforcing this, the expert consensus supports the fact that this is an effective solution for a growing problem.
• Further support comes from the fact the harder-to-quantify downsides to the intervention (e.g. lower freedom of choice) are comparatively low.

Our detailed cost-effectiveness analysis can be found here, as can the full report can be read here.

• Introduction: This report on hypertension is the culmination of three iterative rounds of research: (i) an initial shallow research round involving 1 week of desktop research; (ii) a subsequent intermediate research round involving 2 weeks of desktop research and expert interviews; and (iii) a final deep research round involving 3 weeks of desktop research, expert interviews, and the commissioning of surveys and quantitative modelling. Note also that an initial version of this report was published in July 2023, before being updated with further research in October 2023.
   
• Importance: Globally, hypertension is certainly a problem, and causes a significant health burden of 248 million disability-adjusted life years (DALYs) in 2024, as well as an accompanying net economic burden equivalent to 748 million foregone doublings of GDP per capita, each of which people typically value at around 1/5th of a year of healthy life. And the problem is only expected to grow between 2024 and 2100, as a result of factors like high sodium consumption, ageing, and population growth.
   
• Neglectedness: Government policy is far from adequate, with only 4% of countries currently implementing the top WHO-recommended ideas on sodium reduction, and this not expected to change much going forward – based on the historical track record, any individual country has only a 1% chance per annum of introducing such policies. At the same time, while there are NGOs working on hypertension and sodium reduction (e.g. in China, India and Latin America) – and while some are impact-oriented in focusing on poorer countries where the disease is growing far more rapidly than in wealthier countries – fundamentally, not enough is being done.
   
• Tractability: There are many potential solutions to the problem of hypertension (e.g. reducing dietary sodium, increasing potassium consumption, and pharmacological agents); however, we find that the most cost-effective solution is likely to be advocacy for top sodium reduction policies – specifically: a sodium tax; mandatory food reformulation; a strategic location intervention to change food availability in public institutions like hospitals, schools, workplaces and nursing homes; a public education campaign; and front-of-pack labelling. The theory of change behind this intervention package is as such:
  
  
  • Step 1: Lobby a government to implement top sodium reduction policies.
  • Step 2a: Sodium tax reduces sodium consumption.
  • Step 2b: Mandatory food reformulation reduces sodium consumption.
  • Step 2c: Strategic location intervention reduces sodium consumption.
  • Step 2d: Public education reduces sodium consumption.
  • Step 2e: Mandatory front-of-pack labelling reduces sodium consumption.
  • Step 3: Lower sodium consumption in a single country reduces blood pressure and hence the global disease burden of hypertension
     
• Using the track record of past sodium control and sugar tax advocacy efforts and of general lobbying attempts (i.e. an "outside view"), and combining this with reasoning through the particulars of the case (i.e. an "inside view"), our best guess is that policy advocacy for top sodium reduction policies has a 6% chance of success. Meanwhile, based on various systematic reviews and meta-analyses, and after robust discounts and checks (e.g. for a conservative theoretical prior of a null hypothesis; for endogeneity; or for publication bias), we expect that top sodium reductions policies to significantly reduce sodium consumption: (a) sodium tax (-77 mg/person/day); (b) mandatory food reformulation (-226 mg/person/day); (c) strategic location intervention (-23 mg/day); (d) public education campaign (-35 mg/day); and (e) mandatory front-of-pack labelling (-53 mg/day). Finally, based on a quantitative model we commissioned an external expert epidemiologist – itself using parameters from meta-analyses and other empirical data – we expect that lower sodium consumption of 1mg/person/day in a single country will lead to a 0.000008% reduction in the global disease burden of hypertension.
   
• There are externalities to the top sodium reduction interventions – both positive, like a reduced disease burden of stomach cancer; or negative, like reduced freedom of choice as a result of a sodium tax. However, the impact of these externalities are marginal relative to the burden of hypertension itself (0.7% for stomach cancer) or low (-10% for freedom of choice). What is significant is the gain in cost-effectiveness (around 300%) from implementing the intervention in the most promising countries rather than the average one – that is, those countries suffering from some combination of a higher national disease burden, greater neglect by their governments and NGOs, and state fragility.
   
• Implementation Issues: From our interviews with NGOs working in the space, we find that there is a lack of funding; and this is backed up by observations from the academic literature. However, on the talent side of things, the NGOs we interviewed were more optimistic; they tended to believe that there is not a talent gap.
   
• Outstanding Uncertainties: There are a number of outstanding uncertainties, of which the three most important involve: (a) our use of point estimations (n.b. relying on them is reasonable given that we are ultimately interested in mean estimates, but caution is also warranted, as significant variance is possible); (b) the very simplified methodology we use to project the future disease burden of hypertension; and (c) the highly uncertain estimates of the probability of advocacy success.
   
• Conclusion: Overall, our view is that advocacy for top sodium reduction policies to control hypertension is an extremely cost-effective cause area, and we recommend that nonprofits, grantmakers, policy advocacy organizations, and indeed government themselves, implement the highly-impactful ideas detailed in this report.