In 1978, the US National Heart Lung and Blood Institute held a conference to clarify what was known about mortality from coronary heart disease. Reinforcing existing surveillance, the report also inspired new initiatives: the Atherosclerosis Risk in Communities (ARIC) study in the US; and the World Health Organization MONICA project (MONItoring trends and determinants in CArdiovascular disease). Observing that mortality in the population was the product of coronary event rates and their case fatality, MONICA hypothesised:

A decrease in event rates was driven by a commensurate change in cardiovascular risk factors

Case fatality was reduced by improvements in coronary care. 

Its protocol was followed across 37 populations in 21 countries. Collaborators monitored 10-year population trends in non-fatal myocardial infarction (MI), coronary mortality, coronary care, and risk factors. MONICA’s final results were reported at the turn of the century. On average, two-thirds of the decline in mortality was attributed to falling event rates and one-third to falling case fatality. Across populations case fatality, mortality, and event rates all decreased greatly as coronary care improved. In contrast, ARIC showed that the recent US decline in mortality went with a minimal change in event rates and a greater fall in case fatality. 

Reports since MONICA extend into the new millennium of medical interventions. A Danish study shows a 25-year decline (1984-2008) in both the incidence of those first episodes of MI that involved hospital admission and the associated mortality, even though mortality was exacerbated by comorbidities. Another study by Bandosz showed how changes in treatments and risk factors have contributed to the decline in mortality in Poland since adoption of a market economy. The third study by Smolina and colleagues (see Editor’s Research Choice on page 29) shows a continuing decline in MI and case fatality in England, with a hint of levelling off in the youngest age group. All three studies suggest that the recent decline is associated with the effects of evidence-based treatments in primary prevention, coronary care, and secondary prevention.

Are other factors contributing to the decline? In prevention, coronary risk is multiplicative, so interventions that affect one or two modifiable risk factors disproportionately benefit overall risk. Other and unknown factors are of secondary importance but difficult to dismiss. For example, diet does not operate exclusively through blood cholesterol. 

Similarly, it is difficult to believe that an increase in reductions in coronary case fatalities over three decades, is determined exclusively by drugs. Perhaps patients are now fitter and coronary episodes less severe. Are prevention policies correct and governments in control? Many countries did not have prevention policies until after their decline in mortality from coronary heart disease began. 

In the early 1980s, the then European common market had no mandate to consider human health when subsidising production of animal fats and tobacco. Britain had no coronary prevention policies. Now the European Commission and British health departments have relevant policies in place.

The decline in coronary mortality is predominantly in rich nations, while rates are increasing in other countries. Can these countries learn from us, or must they repeat our mistakes? Standardisation of population risk factor measurements, led by the former MONICA Data Centre in Helsinki, facilitates comparison, prediction, and possible action. Better data from countries where coronary disease is increasing are needed, but motivation and resources may be scarce.