Different ways of attaining the same goal
Different sets of interventions can be used to achieve the same goal and some interventions will reduce the burden associated with multiple risk factors and diseases. Interventions to reduce blood pressure, cigarette smoking and cholesterol all reduce cardiovascular disease, and each has been used separately and together with others at different times and in different settings. The effect of doing two at the same time might be more than would be expected by adding the benefits of doing the two interventions singly, or might be less. Much ischaemic heart disease mortality that has traditionally been attributed to particular risk factors is, in fact, caused by those factors in combination with other risk factors (16). Partly as a result of these interactions, risk reduction strategies are generally based on a combination of interventions rather than just one.
The decision about which combination should be undertaken for the available resources is complex. It is necessary to determine the health gains, and the costs, of doing each possible intervention by itself and in combination with the other ways of reducing the burden for a given risk factor or disease. The analysis undertaken for this chapter followed that process by evaluating what would be achieved by each intervention alone and in combination with other interventions.