Triggering of cardiac events by sexual activity: findings from a case-crossover analysis.

Although anecdotal reports have suggested that sexual activity increases the risk of acute myocardial infarction (MI), controlled studies to evaluate the magnitude of this risk have only recently been conducted. Using an epidemiologic technique called the case-crossover method, the Myocardial Infarction Onset Study (MIOS) has provided quantitative data on sexual activity as a trigger of MI onset. Sexual activity was found to double the relative risk of acute MI in healthy individuals and patients with a prior history of angina or MI. However, the absolute risk of sexually triggered MI remains extremely low, because the baseline risk of MI is low for most individuals and the increased risk due to sexual activity is transient. Regular exercise also was found to reduce the risk of MI by sexual activity. Given that >12 million people in the United States have coronary artery disease, these findings should be more widely disseminated to reassure patients that, in most cases, sexual activity carries little risk of causing a cardiac event. In the future, advances in research on the triggering of MI are likely to yield new approaches to the prevention of cardiovascular events through prospective identification of the vulnerable plaques that lead to coronary thrombosis, and prophylactic measures to sever the link between triggers and their potentially disastrous consequences.