Incidence and clinical manifestations of sudden death in young adults: a two-decade, nationwide, retrospective, cross-sectional study.

Aim: Sudden death in healthy young adults is a rare but devastating event, and its causes and clinical features are not well understood. We describe the clinical manifestations and causes of sudden death in a nationwide-representative cohort of young adults. Methods: All natural non-traumatic deaths that occurred in the Israel Defense Forces between 2000 and 2024 were systematically investigated by a multidisciplinary review committee. Sudden death was defined as death occurring within 24 h of symptom onset. Demographic data, cardiovascular risk factors, prodromal symptoms, and circumstances of death were collected. Cases were stratified by age of death: 18-25 (younger cohort) and >25 years (older cohort). Results: During 4,928,078.2 person-years, there were 64 individuals (57 men and 7 women) who experienced sudden death; 31 and 33 were under or above 25 years old, respectively. The calculated incidence was 1.23 events per 100,000 person-years. Cardiac causes were identified in 67.7% of deaths in the younger and 87.9% in the older cohort. Non-cardiac etiologies, including metabolic, respiratory, and intracerebral hemorrhage, were observed more frequently in the young (9.7%, 6.5%, and 9.7%) compared with older individuals (3%, 3%, and 0%, respectively). Cardiovascular risk factors were more frequent in older individuals, with all of the following being more prevalent smoking (33.3% versus 6.5%, Conclusion: About half of the patients who had sudden death experienced prodromal symptoms within 24 h, and some of them had cardiovascular risk factors. This highlights the need for broader risk assessment and preventive strategies that address both cardiac and non-cardiac mechanisms.