Associations Between Sleep Behaviors And Cardiovascular Disease Risk In Firefighters

INTRODUCTION: Firefighters are a special population due to the unique physiological demands of shift work, including sleep disruptions and disturbances. Increasing non-fire EMS calls decreases the quality and quantity of on-shift sleep. The leading causes of on-duty death in firefighters are cardiovascular-related. Generally, poor sleep is associated with cardiovascular disease (CVD) risk factors. PURPOSE: The purpose of this study was to examine associations between sleep behaviors and CVD risk in firefighters. METHODS: Sixty-one firefighters (1 female, age = 40.0 ± 11.0 years; service years = 15.7 ± 10.6 years; BMI =28.7 ± 3.6 kg/m2) enrolled in an employer-sponsored wellness program completed a health history questionnaire (including the Pittsburgh Sleep Quality Index (PSQI)), and a health assessment. Responses from these assessments were used to calculate a Framingham CVD Risk Score. PSQI scores were used to determine sleep behaviors on and off-shift. Data was analyzed using SPSS, residual assumptions were verified, and alpha level was set at 0.05. RESULTS: Mean SBP was 127.0 ± 9.2 mmHg. Mean CVD Risk was 7.9 ± 6.2 which is categorized as low risk. Mean vascular age was 45.6 ± 12.7 years and was significantly higher than actual age (p < 0.001). There were significant differences between on and off-shift sleep duration (p < 0.001), disturbance (p = 0.03), quality (p < 0.001), and total PSQI scores (p = 0.002) with worse on-shift sleep. Total PSQI scores indicate that 31.7% of firefighters had poor overall sleep off-shift and 44.4% on-shift. Results of a stepwise linear regression indicated that none of the PSQI component scores significantly predicted Framingham CVD risk score. There was a significant difference in sleep duration at home between firefighters with moderate and high risk (H(1) = 29.3, p = 0.03) with longer duration in the high risk category. There was a significant, moderate, negative correlation between sleep latency at home and systolic blood pressure (ρ = -0.35, p = 0.004). CONCLUSIONS: CVD risk scores for this sample is low. On-shift sleep quality, duration, disturbance, and total scores were significantly worse than off-shift sleep. The small sample size was a limitation of this investigation and future research should examine this relationship with objective measures of sleep and CVD.