Shift work, stress and heart disease among paramedics

Shift work and work-related stress is a rising concern among the workforce population because of the potential link to cardiovascular disease (CVD). While these exposures are common in emergency services, there are few studies examining if these factors increase CVD risk among paramedics. The aim of this dissertation is to address this research gap. The first study examined neuroendocrine activity related to shift work and job strain. Shift workers (n=14) reported higher job strain than daytime workers (n=7) and exhibited neuroendocrine dysregulation through salivary biomarkers (alpha-amylase and cortisol) and subclinical CVD indicators (heart rate variability and endothelial functioning). The sampling protocol developed in this study can be used for future, large-scale field studies. The second and third studies used records of emergency runs attended by British Columbia (BC) paramedics between 1990/1 and 2002 to derive exposures, and administrative records from the BC Linked Health Database to ascertain CVD cases. The second study used a nested case-control design with 11 years follow-up (n = 183 – 742). Three controls were matched per case by age, sex and first year of employment. Results of conditional logistic regression did not support hypotheses that shift work was associated with hypertension, chronic coronary syndrome nor acute coronary syndrome; nor that time away from shift work may reduce the risk of CVD. However, development of novel shift work metrics which incorporated periods of neuroendocrine dysregulation and recovery should be considered in future studies. The third study used a case-crossover design to compare exposures during 4 days prior to onset of acute coronary events to exposures in 4 randomly chosen days in the month prior for each acute coronary case (n=65). Results suggest non-significant increased risks of acute coronary syndrome were associated with busy work days, high-stress emergencies and discrepancies between dispatched information and diagnosis at the scene. A delay in onset of acute coronary events was also observed. Results suggest current psychological debriefing sessions may not be effective and that considerations should be made to improve mental health programs to reduce psychological strain.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat