Epidemiology of Decline in Heart Disease Mortality
To continue a study of premature coronary heart disease mortality among men and women aged 35-54 in Allegheny County, Pennsylvania.
|Study Design:||Observational Model: Natural History|
|Study Start Date:||August 1983|
|Estimated Study Completion Date:||November 1996|
The decline in coronary heart disease mortality apparently began around 1963 in the United States and increased in intensity in later years. In the 35-44 age groups the decline began somewhat later, perhaps around 1968. The decline has been found in all four race sex groups and in all age groups including the very old. This decline has also been noted in many other countries besides the United States. The decline of coronary heart disease mortality could obviously be a function of either a change in incidence or in case fatality or both. During the time of this decline in coronary heart disease mortality a great many changes were occurring both in the care of the cardiac patients and changes in risk factors. The fact that the decline occurred across all age as well as race, and sex groups as well as in many other countries suggested that one single factor may not have accounted for the decline.
It was very unlikely that the decline of sudden death was due to improved out-of-hospital care or an early recognition of symptoms. The three percent per year decline suggested that acute precipitating factors other than the underlying atherosclerosis were the most likely factors to account for the decline, especially in the younger age groups of men.
The study was designed to evaluate whether the decrease in coronary heart disease mortality was real or due to an artifact of certification practices or accuracy of diagnosis. The design was based on the fact that the best opportunity to study the decline was in the 35-44 age group.
A retrospective review was made of all death certificates certified to coronary heart disease, all other cardiovascular deaths, and all non-traumatic but possibly sudden deaths certified by the coroner. The review included autopsy records, coroner's reports, hospital records, information from certifying physicians, and interviews with next-of-kin or witnesses. A determination was made of the contribution to the decline of out-of-hospital sudden death and prior history of heart disease, other diseases, and possibly cigarette smoking. The changing mode of death for in-hospital deaths was also evaluated.