Sudden Cardiac Death Among Firefighters ≤45 Years of Age in the United States

Abstract

Sudden cardiac death (SCD) is the leading cause of death in firefighters. Although on-duty SCD usually occurs in older victims almost exclusively because of coronary heart disease, no studies have examined causation across the career span. In the present retrospective case-control study, cases of SCD in young (aged ≤45 years) firefighters from the National Institute for Occupational Safety and Health fatality investigations (n = 87) were compared with 2 age- and gender-matched control groups: occupationally active firefighters (n = 915) and noncardiac traumatic firefighter fatalities (n = 56). Of the SCD cases, 63% were obese and 67% had a coronary heart disease-related cause of death. The SCD victims had much heavier hearts (522 ± 102 g) than noncardiac fatality controls (400 ± 91 g, p <0.001). Cardiomegaly (heart weight >450 g) was found in 66% of the SCD victims and conveyed a fivefold increase (95% confidence interval [CI] 1.93 to 12.4) in SCD risk. Furthermore, hypertension, including cases with left ventricular hypertrophy, increased SCD risk by 12-fold (95% CI 6.23 to 22.3) after multivariate adjustment. A history of cardiovascular disease and smoking were also independently associated with elevated SCD risk (odds ratio 6.89, 95% CI 2.87 to 16.5; and odds ratio 3.53, 95% CI 1.87 to 6.65, respectively). In conclusion, SCD in young firefighters is primarily related to preventable lifestyle factors. Obesity entry standards, smoking bans, and improved screening and/or wellness program are potential strategies to reduce SCD in younger firefighters.

Pathoanatomic Findings Associated With Duty‐Related Cardiac Death in US Firefighters: A Case–Control Study

“…Importantly, regression of LVH through targeted treatment has been shown to reduce the risk of cardiovascular events 39, 40, 41. Results from this study showing that cardiomegaly and LVH were fairly common among noncardiac trauma controls, who were aged <40 years on average, corroborate the findings of Yang et al12 and suggest that screening at a relatively young age may be justified for firefighters at risk of cardiomegaly.…”

“…The finding of elevated risk of SCD among firefighters with increased heart mass or wall thickness is consistent with findings from a study investigating cardiac death in a cohort of young firefighters. Yang et al12 found that the odds of duty‐related SCD in firefighters aged ≤45 years increased nearly 5‐fold in the presence of cardiomegaly. In population‐based studies, LVH has been shown to be a strong independent predictor of cardiovascular mortality, including SCD,14, 15 and the risk of SCD increased with increasing LV mass 14.…”

“…LVH has been shown to be a strong independent predictor of SCD in the general population,14, 15 but its prognostic power within the general fire service has not been documented. A recent case–control study determined that cardiomegaly (defined as heart weight >450 g), which was found in 61% of SCD cases, was associated with a 5‐fold increased risk of SCD among young (aged ≤45 years) firefighters 12. Moreover, a review of autopsies revealed that 70% of SCD cases in this young cohort had evidence of LVH.…”

“…Left ventricular hypertrophy (LVH) and cardiomegaly have been reported as common secondary findings in SCD attributed to CHD in the general population8, 9, 10, 11 and among firefighters 5, 6, 12, 13. However, the role of LVH and cardiomegaly have not received nearly as much attention as CHD in contributing to sudden cardiac events.…”

“…Prior research has identified occupational16, 17 and individual5, 6, 12 factors associated with an increased risk of cardiac death in the fire service. Careful analysis of autopsy data offer the opportunity to better understand the underlying pathoanatomic features associated with SCD.…”