Sudden cardiac death in young athletes is very rare. The estimated yearly rate varies from one country to another, however. In the United States, it is estimated that 1 out of 200,000 to 1 out of 100,000 high school athletes dies suddenly while participating in sports. By comparison, in Italy the rate of sudden death among athletes is estimated to be about 3 in 100,000, while in Norway the rate is estimated to be just under 1 in 100,000.
The differences in rates of sudden death may be due to differences in the mix of ages or genders in the groups studied, or it may reflect population-wide differences in the genetic make-up of the athletes.
Participation in sports does seem to increase the risk of sudden death, however small. For example, a study from Italy found that teens and young adults who play sports were nearly three times as likely to die suddenly when compared to people of a similar age who did not play sports.