Background: It has been shown that the prevention of multicausal diseases such as heart attack (at an individual level) should be guided by absolute risks rather than by the level of risk factors. Here, we show that an analogous argument should form the basis of population-level prevention.
Methods: Estimates of age- and sex-specific means and standard deviations for systolic blood pressures and blood cholesterol concentrations and for deaths assigned to all vascular causes in 2002 were obtained from the World Health Organization for 25 current member states of the European Union, for the ages 30-69 years. Predicted effects of 5 mmHg reductions in mean systolic blood pressures and 0.5 mmol l(-1) reductions in mean total blood cholesterol concentrations on deaths and years of life lost (YLL) per 100,000 person-years from vascular diseases were modelled using proportional risk coefficients from meta-analyses of cohort studies and randomized controlled trials.
Results: Potential absolute benefits were strongly positively associated with current levels of absolute mortality risk: in the case of systolic blood pressure, predicted vascular deaths averted in the highest risk populations (Romania, Bulgaria) were over five times higher than in the lowest risk populations (Spain, France). Potential benefits were only weakly related to existing levels of the risk factor of interest.
Conclusions: High-risk populations should give the highest priority to achieving favourable shifts in all modifiable risk factors. Irrespective of the level of any particular risk factor, the rewards will be greatest in these populations.