Background Between 2001 and 2011, UK adult salt-intake fell by 15%, reflecting a comprehensive strategy led by the Food Standards Agency. Yet hypertension remains common in the UK, suggesting that further progress on salt-reduction could bring additional public health benefits. However, it is unclear how the overall effect of such policies might impact socio-economic class (SEC) inequalities in cardiovascular health. Our study therefore aimed to help inform decision making on salt-reduction policies during the next UK parliament, 2015 to 2020.
Methods We extended the IMPACTSEC socially-stratified epidemiological model. We linked policy effects on salt, via systolic blood pressure, to premature CHD deaths (ages 35–74 years) in England 2015 to 2020. We used data from the Health Survey for England, published meta-analyses, and the Office for National Statistics. SEC was quantified by quintiles of the Index of Multiple Deprivation. We assessed the effects of product reformulation (voluntary or mandatory), social marketing and nutrition labelling against a forecast counterfactual of premature CHD deaths. We supplemented the scarce evidence-base on key policy parameters with expert opinion. Ten experts participated; all were scientists or policy experts in the academic or non-governmental sectors. Expert data were obtained using a pre-piloted, one-page questionnaire on the perceived effectiveness and inequality of salt-reduction interventions up to 2020. For each parameter, we elicited best, minimum, and maximum estimates. We estimated each intervention’s impact on inequality by its effect on the mortality gap between the least and most deprived SEC groups. Uncertainty was quantified using probabilistic sensitivity analysis.
Results Our results suggest that, measured cumulatively over our study period, mandatory reformulation might prevent or postpone approximately 8300 premature CHD deaths (95% confidence interval: 5300, 11400) and reduce the inequality gap by some 1800 (1200, 2600) deaths. Voluntary reformulation could prevent or postpone approximately 1000 (200, 3800) deaths and reduce inequality by approximately 200 (0, 900) deaths. The estimated effects of behaviour change policies (social marketing and labelling) appeared much weaker: each might prevent or postpone approximately 100 (0, 400) deaths. They also had negligible effects on inequality: social marketing might change inequality by –6 (–50, 20) deaths and labelling by –4 (–50, 20) deaths.
Conclusion Our model for England suggests that reformulation could be the most effective and equitable intervention against premature CHD deaths, especially if mandatory. By contrast, social marketing and labelling might have relatively little impact on the number of deaths or inequality.
- public health