UC Irvine

On-the-job deaths due to cardiovascular events are the most common cause of death among firefighters across the U.S. consistently every year since 1977. Work stress is prevalent in the firefighting occupation most often secondary to the strenuous nature of their job duties that can include emergency situations that are sometimes life-threatening and extremely long shift hours. Work stress can contribute to strain or the negative manifestations of stress reactions, which can present mentally and/ or physically. There is extensive literature on the association of psychological strain and metabolic syndrome (MS), which is an indicator of cardiovascular disease risk. Consequently, based on the current literature and known pathophysiology, a causal association between work stress, MS, and cardiovascular disease is biologically plausible. Thus, screening for psychological occupational strain may potentially reveal modifiable cardiovascular risk factors to target in disease prevention efforts.

However, the association between work stress, MS, and cardiovascular disease is understudied in firefighters. This study is the first to examine this relationship in this unique occupational group. In this study, an extensive literature review and cross-sectional analysis of data from firefighters in Southern California was performed. Psychological strain was investigated through measures of mental health, emotional exhaustion, and post-traumatic stress disorder (PTSD) risk indicators through the General Health Questionnaire-12 (GHQ-12), Exhaustion Scale of the Maslach Burnout Inventory (ES-MBI), and the primary care PTSD (PC-PTSD) screening questionnaires. MS was assessed with data on each component of MS, which included waist circumference (WC), fasting glucose, triglycerides (TG), high density lipoprotein (HDL), and blood pressure (BP). Data analysis revealed statistically significant relationships between GHQ-12 and WC, ES-MBI and TG, and PC-PTSD and WC even after controlling for covariates of age and gender. The analysis revealed negative associations between psychological screening tests and MS (and its components), which are unexpected considering the pathophysiology of cardiovascular strain resulting from stress. Due to potential effects of medications on associations with well-controlled components of MS, such as reverse causality, a sensitivity analysis was performed excluding those on medications. This analysis revealed a stronger statistically significant association with GHQ-12 and WC and more consistent positive associations between psychological screening tests and MS that were apparently negative in the initial analysis. Otherwise no other statistically suggestive associations were found. Furthermore, no statistically significant relationships were found with the number of MS criteria and MS itself.

This study reveals possible associations with indicators of psychological occupational strain and metabolic syndrome (and its components). Due to individual variability of reactions to stressors, indicators of psychological strain were used instead of measures of work stress. Despite the multiple strengths of this study, there are also several limitations making further research on this topic necessary in order to make more definitive conclusions about causation. Further investigation is important in informing prevention programs and achieving the overarching goal of decreasing firefighter morbidity and mortality while increasing quality of life through early intervention and prevention of adverse cardiovascular outcome.