Heart Diseases of Uncertain Etiology: A New Definition of Heart Failure for Epidemiological Studies

In Search of Risk Factors: The Origin and Early Stages of Cardiovascular Epidemiology

Based mainly on their personal experience, the authors try to describe the origin of cardiovascular disease (CVD) epidemiology and the problems and difficulties practitioners attempted to tackle and solve during the first few decades of this discipline, which started around the middle of the last century. Beyond identifying the characteristics of those who became CVD epidemiologists, a description is given of the initial structures of the involved studies, participation rates, risk factors measurements and standardization, clinical measurements and diagnostic criteria, mortality data collection and coding, data loading and analysis, plus a number of problems still unsolved at the beginning of the 2000s. Despite many obstacles, and the initial hostility of the medical-scientific establishment, CVD epidemiology represented a revolution in researching in the bio-medical field. In the end, it also affected clinical research introducing the use of the quantitative approach bound to mathematical-statistical procedures. After decades of hard work and the development of a number of innovative tools, CVD epidemiology received its deserved recognition, eventually being accepted as a reputable and independent scientific discipline. Yet, in several countries, especially those from Southern Europe, an academic recognition of CVD epidemiology is still lacking.

Cardiovascular Mortality in 10 Cohorts of Middle-Aged Men Followed-Up 60 Years until Extinction: The Seven Countries Study

OBJECTIVES

To investigate mortalities from three major groups of cardiovascular diseases (CVDs) in a pooled cohort and followed up until extinction.

MATERIALS AND METHODS

Ten cohorts of men (N = 9063) initially aged 40-59, in six countries, were examined and followed-up for 60 years. The major CVD groups were coronary heart disease (CHD), cerebrovascular diseases (STROKE) and other heart diseases of uncertain etiology (HDUE).

RESULTS

Death rates from CHD were higher in countries with high serum cholesterol levels (USA, Finland and The Netherlands) and lower in countries with low cholesterol levels (Italy, Greece and Japan), but the opposite was observed for STROKE and HDUE, which became the most common CVD mortalities in all countries during the last 20 years of follow-up. Systolic blood pressure and smoking habits were, at an individual level, the common risk factors for the three groups of CVD conditions, while serum cholesterol level was the most common risk factor only for CHD. Overall, death rates for the pooled CVDs were 18% higher in North American and Northern European countries, while CHD rates were 57% higher in the same countries.

CONCLUSIONS

Differences in lifelong CVD mortalities across different countries were smaller than expected due to the different rates of the three groups of CVD, and the indirect determinant of this seemed to be baseline serum cholesterol levels.