Hypothesis: The recent decline in coronary heart disease mortality - Mainly a shift from fatal to non-fatal events?

Objectives-A marked, sequential decline in coronary heart disease (CHD) mor tality is established, but not its causes. Does it reflect modern treatment effects or a spinoff of primary prevention? The aim of this study was to e xplore this issue using a prospective cohort follow-up design. Design-In 1972-1975 and 1980-1982 Cohorts 1 (n = 613) and 2 (n = 667) of id entical age (males, mean 56 years) were examined, and thereafter followed c losely for 14 years. CHD risk- and treatment patterns, incidence of non-fat al myocardial infarctions (MIs) and total-, cardiovascular and CHD mortalit y rates were studied. Results-CHD risk factors were more favourable, medical treatment more aggre ssive and 14-years CHD mortality, as expected, lower in Cohort 2 (7.7%/4.8% , p = 0.032). However, hospital- and prospective ECG data revealed opposite trends in non-fatal cohort CHD incidence, and aggregated numbers of CHD de aths and non-fatal MI cases were 16.7%/16.0% in Cohort 1/2 (p = 0.90). Conclusions-A marked, sequential reduction in CHD mortality was followed by a reciprocal increase in non-fatal MIs. This phenomenon may prevail in low CHD-endemic areas, and may call for altered primary preventive measures fo r reduction in total CHD incidence.