Age is by far the most powerful risk factor for cardiovascular disease. Moreover, the consequences of age are considered inevitable and irreversible. In this study, we examined whether age is, to a major degree, a modifiable risk factor. In the subjects in the Apolipoprotein-related Mortality Risk (AMORIS) study, we show that fatal myocardial infarction (MI) is uncommon in men before the sixth decade and in women before the seventh. In age-adjusted analyses, the risk of fatal MI increase successively with each decile of the apolipoprotein (apo) B/apoA-I ratio, confirming the importance of the balance of the atherogenic and antiatherogenic lipoproteins as a fundamental determinant of the likelihood of clinical events. We then determined the risk of fatal acute MI over time in the highest decile of the apoB/apoA-I ratio compared with the lowest decile. For the purposes of this analysis, we assume that all events in the lowest decile of the apoB/apoA-I ratio represent the nonmodifiable adverse effects of age. This assumption maximizes the irreversible effects of age. Because the change in age is identical for the subjects in both deciles, the difference in risk between the lowest and highest deciles of the apoB/apoA-I ratio represents the consequence of exposure over time to very high values of this ratio. Exposure is the modifiable element of risk, and it contributed to most of the risk. In conclusion, it appears that not all of the effects of age are irreversible. therefore, outcomes with early prevention might be much more favorable than usually assumed.