Classical risk factors and their impact on incident non-fatal and fatal myocardial infarction and all-cause mortality in southern Germany Results from the MONICA Augsburg cohort study 1984–1992

BACKGROUND: The MONICA (Monitoring Trends and Determinants in Cardiovascular Diseases) project in Augsburg provides the first population-based cohort study in Germany to quantify the associations of the risk factors hypertension, hypercholesterolaemia and smoking with incident non-fatal and fatal myocardial infarction and all-cause mortality, and to assess their impact at the population level. METHODS: The cohort comprises 1074 men and 1013 women aged 45-64 years; they were followed over 8 years from 1984-1992. In the men, there were 61 non-fatal and fatal myocardial infarctions and 92 all-cause mortality events over this period; in the women the number of deaths from all causes was 45. Incidence rates, hazard rate ratios, population attributable fractions and rate advancement periods were calculated. RESULTS: Adjusting for confounders, the myocardial infarction hazard rate ratios for men with hypertension, or a total cholesterol/HDL-cholesterol ratio > or =5.5, or smoking > or =20 cigarettes/day, were 2.0 (95% CI 1.2-3.5), 2.9 (95%, CI 1.7-5.0), and 2.7 (95% confidence interval (CI) 1 4-5.0), respectively. The risk factor combination total cholesterol/HDL cholesterol ratio > or = 5.5 and cigarette smoking was particularly hazardous. The three risk factors contributed 65% of the burden of myocardial infarction in the population. The rate advancement period for myocardial infarction associated with hypertension, total cholesterol/HDL cholesterol ratio > or =5.5 or smoking > or =20 cigarettes/day was 8.3, 12.4 and 11.5 years, respectively. In women, these risk factors were similarly predictive of all-cause mortality. Comparing the cohort data from Augsburg with those of two occupational cohorts from Germany reveals higher absolute myocardial infarction risks in the Augsburg population; however, the relative risk estimates in the Augsburg and the two occupational cohorts were very similar. CONCLUSION: Our results confirm the important contribution of the classical risk factors to the risk of myocardial infarction and all-cause mortality in Germany. The results pertaining to the concept of rate advancement periods particularly demonstrate the great potential for prevention.