Abstract

BACKGROUND: Plasma fibrinogen is considered as a positive mediator between mental stress and cardiovascular disease because it is an acute-phase protein released in response to mental stress and a coagulation factor. However those three factors have never been studied together within a single integrated framework, using cardiac troponin T as a marker of cardiovascular risk. METHODS: 491 disease-free men and women aged 53-76 were tested for fibrinogen levels before, immediately after, and following recovery from standardized mental stress tasks. We measured plasma cardiac troponin T using a high-sensitivity assay (HS-CTnT) and coronary calcification using electron-beam dual-source computed tomography. RESULTS: The average fibrinogen concentration increased by 5.1% (s.d.=7.3) in response to stress and then tended to return to baseline values. People with higher baseline fibrinogen values had smaller increases (blunted responses) following the stress task (P=0.001), and people with higher stress responses showed better recovery (P<0.001). In unadjusted analyses, higher baseline fibrinogen was associated with higher chances of having detectable HS-CTnT (P=0.072) but, conversely, higher fibrinogen response was associated with lower chances of having detectable HS-CTnT (P=0.007). The adjustment for clinical, inflammatory, and haemostatic factors, as well as for coronary calcification eliminated the effect of baseline fibrinogen, whereas the negative association between fibrinogen response and HS-CTnT remained robust: the odds of detectable HS-CTnT halved for each 10% increase in fibrinogen concentration due to stress (OR=0.49, P=0.007, 95% CI=0.30-0.82). CONCLUSIONS: Greater fibrinogen responses to mental stress are associated with lower likelihood of detectable high-sensitivity troponin T plasma concentration. A more dynamic fibrinogen response appears to be advantageous for cardiovascular health.