Can we still learn from the Seven Countries Study?

Abstract

The Seven Countries Study (SCS) of Cardiovascular Diseases started midway last century and was the pioneer investigation of coronary heart disease (CHD) at international level. The 16 cohorts of middle-aged men enrolled in eight nations of seven countries allowed to show large differences of CHD incidence and mortality across different cultures, partly explained by average levels of serum cholesterol and dietary habits, that is, Western type patterns in the high-risk populations, and Mediterranean or Oriental type in Southern Europe and Japan. Later, critics to the validity of the study were largely based on fake news, wrong or distorted information uncritically transmitted in a cascade of media. Recent analyses based on 45-50 years of follow-up showed and confirmed that diet patterns were associated with all-cause mortality and age at death; that multivariate coefficients of major risk factors of CHD were not heterogeneous across different populations and cultures; that analysis of competing risks of CHD versus other conditions identified serum cholesterol as the critical determinant; that true CHD manifestations had different determinants compared with Heart Diseases of Uncertain Etiology frequently confused with CHD. The SCS can still teach investigators and scholars of cardiovascular epidemiology, if old contributions are carefully read and interpreted; it is still recognized as the seminal study in this area at international level although it had limits as any other study but represented the first step into the identification of the relationship of diet with CHD and mortality across populations, and of the Mediterranean diet.