Long-term time-related predictivity of coronary events as a function of a single measurement of serum cholesterol and systolic blood pressure

Objective - To study the ti me-related association of a single measurement of serum cholesterol and systolic blood pressure with the occurrence of a f irst coronary event in a population sample of middle-aged men. Methods and results - A single measurement of serum total cholesterol and s ystolic blood pressure (along with age, cigarette consumption, physical act ivity at work and body mass index as possible confounders) was made in 1,60 5 coronary disease-free men aged 40-59 belonging to the Italian rural cohor ts of the Seven Countries Study. During 25 years of follow-up 353 men devel oped a first event, that is a coronary death (sudden or not), and definite or possible myocardial infarction. Twenty-five partitioned proportional haz ards models were solved, one for each independent year of follow-up, to pre dict the risk of incident events. Single-year hazard functions, separately for serum cholesterol and systolic blood pressure, were cumulated and smoot hed. The resulting curves showed a regularly increasing risk for coronary e vents. They fit straight lines, with large correlation coefficients for bot h serum total cholesterol (r = 0.99) and systolic blood pressure (r = 0.99) . These slopes were similar to the coefficients estimated by a single propo rtional hazards model solved for all events during 25 years. Conclusion - A single measurement of serum total cholesterol and systolic b lood pressure in middle aged-men maintains a regular and monotonic relation ship with occurrence of a first coronary event during 25 years of follow-up .