Forty-year coronary mortality trends and changes in major risk factors in the first 10 years of follow-up in the seven countries study

Abstract

Time trends in coronary heart disease (CHD) mortality during a 40-year follow-up were studied in the Seven Countries Study. Thirteen cohorts of men aged 40-59 at entry were enrolled in seven countries (USA, Finland, the Netherlands, Italy, Serbia, Greece and Japan) for a total of 10,628 subjects. Cardiovascular risk factors were measured at entry and at the 10-year follow-up examination and coronary heart disease mortality data collected during 40 years. During the 40-year follow-up, the hazard rate of the Weibull parametric distribution (annual conditional risk of death) for CHD mortality tended to slightly decline in the US, Finnish, Dutch and Japanese cohorts, moderately increased in Italy and exponentially increased in cohorts of Serbia and Greece. A strong positive association was found between the shape of the hazard curve, describing the acceleration of the hazard, and a score of population mean risk factor changes (serum cholesterol, systolic blood pressure and smoking prevalence) observed during the first 10 years of follow-up, with a correlation coefficient of 0.91 between the two indicators. The countries with a relative decline in the annual hazard function were the same where, during the same historical period, large decreases in official death rate from CHD were recorded, and viceversa. The acceleration in mortality risk for CHD mortality in different countries, described by the shape of the Weibull distribution, is related to changes in mean levels of major coronary risk factors.