Firefighters do not have impaired endothelial function or increased cardiovascular risk compared to police officers (FIRECOP)

Abstract

Background: Firefighters are at high-risk of cardiovascular death on-duty compared to other occupations, with coronary heart disease accounting for 45% of deaths amongst firefighters, 22% of deaths in police officers and 15% of all deaths at work. We compare traditional cardiovascular risk factors and vascular endothelial function in firefighters and a matched group of police officers with similar occupational responsibilities. Methods: Eighteen healthy, non-smoking firefighters and 18 matched police officers (age 41±7 years, 16 males) were randomly selected for cardiovascular risk assessment including ambulatory blood pressure and cardiopulmonary fitness testing in Edinburgh, Scotland. All volunteers underwent an assessment of vascular function whilst off-duty. Bilateral forearm blood flow was measured before and during unilateral intra-brachial infusion of bradykinin (100-1,000 pmol/min), acetylcholine (5-20 μg/min), sodium nitroprusside (2-8 μg/min), and verapamil (10-100 μg/min). Results: Firefighters and police officers had similar body mass index (28±3 versus 28±3 kg/m2, P=0.78) and cardiopulmonary fitness (VO2 max 34±10 versus 34±5 ml/kg/m2, P=0.58). Blood pressure, heart rate, lipid concentrations and Framingham Risk Scores (6.6±5.3 versus 6.6±4.7) were similar between groups (P>0.05 for all). There was a dose-dependent increase in forearm blood flow with each vasodilator (P<0.01 for all), with no difference in response to bradykinin (P=0.97), acetylcholine (P=0.85), sodium nitroprusside (P=0.84) or verapamil (P=0.77) between groups. Conclusion: Firefighters have similar cardiovascular risk profiles to police officers and do not have impairment of vasomotor endothelial function whilst off-duty. We suggest that the excess of cardiovascular events and deaths on-duty in firefighters are due to the acute and transient effects of extreme physical exertion, psychological stress, heat and exposure to air pollutants.