Background Sudden cardiac death associated with physical exertion (SCD/E) is a complicated pathophysiological event. This study aims to calculate the incidence rate of SCD/E in the US military population from 2005 to 2010, to characterise the demographic and cardiovascular risk profiles of decedents, and to evaluate aetiologies of and circumstances surrounding the deaths.

Methods Perimortem and other relevant data were collected from the Armed Forces Medical Examiners Tracking System, Armed Forces Health Longitudinal Technology Application, and Defense Medical Epidemiology Database for decedents meeting SCD/E case definition. Incidence rates were calculated and compared using negative binomial regression.

Results The incidence of SCD/E in the Active Component (ie, full-time active duty) US military from 2005 to 2010 was 1.63 per 100 000 person-years (py): 0.98 and 3.84 per 100 000 py in those aged <35 and ≥35 years, respectively. Atherosclerotic cardiovascular disease was the leading cause of death overall (55%) and in the ≥35-year age group (78%), whereas the leading cause of death in the <35-year age group (31%) could not be precisely determined and was termed idiopathic SCD/E (iSCD/E). SCD/E was more common in males than females (incidence rate ratio (IRR) = 5.28, 95% CI 2.16 to 12.93) and more common in blacks than whites (IRR=2.60, 95% CI 1.81 to 3.72). All female cases were black.

Conclusions From 2005 to 2010, the incidence of SCD/E in US military members aged <35 years was similar to most reported corresponding civilian SCD rates. However, the leading cause of death was iSCD/E and not cardiomyopathy. Improved surveillance and age-based prevention strategies may reduce these rates.