The incidence of sudden cardiac death (SCD) among young athletes is estimated to 
be 1-3 per 100,000 person years, and may be underestimated. The risk of SCD in 
athletes is higher than in non-athletes because of several factors associated 
with sports activity that increase the risk in people with an underlying 
cardiovascular abnormality. A clear gender difference in the incidence of SCD 
exists in young athletes, with the risk in male athletes being up to 9 times 
higher than in female athletes. The most common causes of SCD in young athletes 
is underlying inherited/congenital cardiac disease, such as cardiomyopathies, 
congenital coronary anomalies and ion channelopathies. Blunt chest trauma also 
may cause ventricular fibrillation in a structurally normal heart, known as 
commotio cordis. Although geographical differences in the causes of SCD in young 
athletes have been reported, these disparities are more likely to be related to 
the type and implementation of pre-participation screening leading to the 
identification of athletes at risk, rather than reflecting a truly different 
ethiology. More studies are needed to clarify the role of ethnicity in the 
prevalence of diseases known to cause SCD in young athletes.