The Seven Countries Study has shown that population mortality rates for various chronic diseases are related to diet and smoking. This paper addresses the associations between diet, smoking and 25-year all-cause mortality.
Baseline surveys were carried out between 1958 and 1964 on 12,763 middle-aged men constituting 16 cohorts in seven countries. In 1987/88 equivalent food composites representing the average food intake of each cohort at baseline were collected and chemically analysed in one central laboratory. During 25 years of follow-up 5973 men died and age-adjusted population mortality rates were calculated for each cohort.
Multivariate linear regression analyses showed that the population intake of saturated fat and the prevalence of smoking were positively associated with population all-cause mortality rates. Population vitamin C intake was inversely associated with all-cause mortality. It was calculated that a reduction in saturated fat intake of 5% of energy, a 20 mg/d increase in vitamin C and a 10% decrease in the prevalence of smokers may decrease the 25-year all-cause population mortality rate by 12.4% (95% CI: 5.6, 19.4%) at an average population all-cause mortality rate of 45%.
At the population level saturated fat, vitamin C and cigarette smoking are important determinants of all-cause mortality.