Seismocardiographic Evidence of Deteriorating Cardiac Function Among Canadian Police Officers: Evidence from the Longitudinal Royal Canadian Mounted Police Posttraumatic Stress Disorder Study

Why was the study done?

Royal Canadian Mounted Police (RCMP) frequently encounter potentially psychologically traumatic events (PPTEs) which include direct (e.g., happened to me) or indirect (e.g., part of my job) exposure to actual or threatened death, serious injury, or sexual violence, and subsequently demonstrate an increased risk of developing posttraumatic stress injuries (PTSIs). Common PTSIs among RCMP members include posttraumatic stress disorder, generalized anxiety disorder, and major depressive disorder, and conditions related to PTSIs, such as alcohol use disorder, although associations between PPTE exposures and physical comorbidities such as neurological and cardiovascular conditions have also been evidenced. Assessments of cardiac function at pre-training and pre-deployment indicated that RCMP cadets exhibited excellent cardiovascular health, but no longitudinal assessments of cardiac function had been conducted prior to the current study.

What was done in the study?

The current study was designed to assess for changes in cardiac function among RCMP within their first three years of field service. Participants (n=96) were mostly male (71.6%), men (71.6%), and White (85.6%), with a mean age of 30.22±6.22 years. Measurements of cardiac function were obtained using seismocardiography. Participants were instructed to collect 60 seconds of data each day at a consistent time. The current study includes values from a single recording captured within 30 days of a participant’s annual assessment interval (i.e., one recording from pre-deployment, 1-year follow-up, 2-year follow-up, and 3-year follow up). A series of unadjusted and covariate adjusted linear mixed models (LMMs) were conducted to assess for changes in measures of cardiac function over time. Additionally, the point prevalence of possible ventricular diastolic dysfunction derived from the myocardial performance index (MPI) value at each of the annual assessment intervals was computed.

What did we find out?

The current results suggest that despite considerable variations in individual trajectories among RCMP officers in their first 3 years of service, measures of diastolic cardiac function began to change as early as the second year of service, with compensatory changes in systolic function occurring concurrently, or observed after the third year of service. No RCMP at either pre-deployment and 1-year follow-up demonstrated MPI values suggestive of altered myocardial function, while 5.7% of the sample at 2-year follow-up, and 38.3% of the sample at 3-year follow-up demonstrated MPI values suggestive of altered myocardial function. Consistent with a priori pre-registered hypotheses, the current results demonstrate longitudinal changes in cardiac function, albeit at a rate that seemingly exceeds what would be considered consistent with healthy aging. The current results also bolster notions that PTSI prevalence among RCMP is related to service experiences, and support the continued development and deployment of organization-level PTSI mitigation strategies for all RCMP.