A pool of two Italian rural population samples made up of 1,712 men aged 40-59 at entry was studied in 1960 and than followed up for 25 years. The multivariate analysis of the first major coronary event using the Cox model showed, in men aged 40-59, 45-64 and 50-69, the significant predictive role of age, systolic blood pressure, serum cholesterol and cigarette smoking, but not of body mass index, without marked differences attributable to the aging process. Changes in systolic blood pressure, serum cholesterol and cigarette smoking occurring between year 0, 5 and 10 of follow-up, as defined by two different indicators, increased significantly the predictability of coronary events occurring between years 10 and 25 of follow-up when added to the model including the baseline factors. It is inferred that increases and decreases (even of relative nature) of the three major risk factors around the entry levels are associated with higher and lower levels of coronary risk in the 15 years after the changes have occurred.