What are the implications of routine aspirin use for adults <40 and >70 years of age? 
For adults <40 years of age, there is insufficient evidence to judge the risk benefit ratio of routine aspirin for the primary prevention of ASCVD. However, one caveat is that, although routine use is not recommended in these settings, there is also insufficient evidence to comment on whether there may be select circumstances in which physicians might discuss prophylactic aspirin with adults <40 years of age or >70 years of age in the context of other known ASCVD risk factors (eg, strong family history of premature MI, inability to achieve lipid or BP or glucose targets, or significant elevation in coronary artery calcium score). Prophylactic aspirin in primary-prevention adults >70 years of age is potentially harmful and, given the higher risk of bleeding in this age group, difficult to justify for routine use.