Do episodes of anger trigger myocardial infarction? A case-crossover analysis in the Stockholm Heart Epidemiology Program (SHEEP)

Objective: Our objectives were to study anger as a trigger of acute myocard ial infarction (MI) and to explore potential effect modification by usual b ehavioral patterns related to hostility. Methods: This study was a case-cro ssover study within the Stockholm Heart Epidemiology Program. Exposure in t he period immediately preceding MI was compared with exposure during a cont rol period for each case. From April 1993 to December 1994, 699 patients ad mitted to corollary care units in Stockholm County were interviewed. Result s: During a period of 1 hour after an episode of anger, with an intensity o f at least "very angry," the relative risk of MI was 9.0 (95% CI, 4.4-18.2) . In patients with premonitory symptoms, the lime of disease initiation may be misclassified. When restricting the analyses to those without such symp toms, the trigger risk was 15.7 (95% CT. 7.6-32.4). The! possibility of exa mining effect modification was limited by a lack of statistical power (eigh t exposed cases). Results of the analyses suggested, however, an increased trigger effect among subjects reporting nonhostile usual behavior patterns. nonovert strategies of coping with aggressive situations (not protesting w hen being treated unfairly), and nonuse of P-blockers. Conclusions: The hyp othesis that anger may trigger MI is further supported, with an increased r isk lasting for approximately 1 hour after all outburst of anger. It is sug gested that the trigger risk may be modified by personal behavior patterns.