IMPACTNCD key assumptions
| Population module | Migration is not considered. |
| Social mobility is not considered. | |
| QIMD is a marker of relative area deprivation with several versions since 2003. We considered all version of QIMD identical. | |
| We assume all salt that is consumed is excreted from urine and all urine sodium comes from salt consumption. | |
| We assume that the surveys used are truly representative of the population. | |
| We assume that the decline in salt consumption observed since 2003 was fully attributable to the implemented policy. | |
| Disease module | We assume multiplicative risk effects. |
| We assume log-linear dose–response for the continuous risk factors. | |
| We assume that the effects of the risk factors on incidence and mortality are equal and risk factors are not modifying survival. | |
| We assume 5-year mean lag time for CVD and 8-year for GCa (except for the cumulative effect of smoking on GCa where lag was assumed similar to CVD one). | |
| We assume 100% risk reversibility. | |
| We assume that trends in disease incidence are attributable only to trends of the relevant modelled risk factors. | |
| Only well-accepted associations between upstream and downstream risk factors that have been observed in longitudinal studies are considered. However, the magnitudes of the associations are extracted from a series of nationally representative cross-sectional surveys (Health Survey for England). | |
| For GCa, we assume that survival of 10 years after diagnosis equals remission. |
CVD, cardiovascular disease; GCa, gastric cancer; QIMD, quantile group of Index of Multiple Deprivation.