Coronary heart disease in seven countries.
Ancel Keys' 1970 report compared five-year coronary heart disease incidence among 12,770 men aged 40–59 across Finland, Greece, Italy, Japan, the Netherlands, the United States and Yugoslavia, examining population differences alongside blood pressure, serum cholesterol, smoking, body size, physical activity and diet.
What the study did and found
Ancel Keys' 1970 article “Coronary heart disease in seven countries.” reported findings from an international cooperative study of 12,770 men aged 40–59 in Finland, Greece, Italy, Japan, the Netherlands, the United States and Yugoslavia, with re-examination after five years. The report describes marked differences in coronary heart disease mortality between countries, with higher proportions of deaths attributed to coronary disease in the United States and Finland than in several other cohorts. Smoking, body fatness and relative body weight did not explain the population differences in this analysis. Higher coronary incidence tended to occur where hypertension and serum cholesterol were more prevalent and diets contained more saturated fatty acids. Habitual physical activity was not significantly related to incidence in this five-year comparison. These were observational associations and did not by themselves establish causation.
Why it is cited
The paper is cited as part of the Seven Countries Study, an early cross-national investigation of coronary disease epidemiology. Later historical and methodological reviews discuss the programme for its contribution to population comparison, cardiovascular survey methods and the development of hypotheses linking diet, serum cholesterol and coronary risk.
Subsequent research has strengthened some of the associations examined in this early work while refining others. High LDL-related cholesterol, elevated blood pressure and cigarette smoking are now established major risk factors for atherosclerotic cardiovascular disease. Dietary evidence is also more specific: reducing saturated fat is most beneficial when it is replaced with unsaturated fats rather than refined carbohydrate. Physical activity, which was not significantly associated with coronary incidence in this particular five-year population comparison, is now recognised as part of cardiovascular prevention. The original report should therefore be read as an influential observational study, not as a complete modern risk model.
The topic today
Modern coronary prevention uses multivariable risk assessment rather than a single population-level factor. Contemporary guidelines consider cholesterol, blood pressure, smoking, diabetes, adiposity and other clinical or social modifiers, while treatment combines lifestyle measures with medication when indicated. The Seven Countries Study also continued for decades, allowing later analyses of long-term mortality and changing risk patterns. Its historical value lies in showing how international differences in coronary disease helped generate questions that were later tested with longer follow-up, clinical trials and mechanistic research.