Is type A behavior really a trigger for coronary heart disease events?
Gallacher JE., Sweetnam PM., Yarnell JW., Elwood PC., Stansfeld SA.
OBJECTIVE: The purpose of this study was to compare chronic with acute mechanisms by which Type A might predict incident coronary heart disease (CHD). METHOD: The study included 2394 men aged 50 to 64 years who were assessed for CHD, Type A behavior, and CHD risk factors. Type A was assessed using the Jenkins Activity Survey (JAS), the Bortner scale, and the Framingham scale. Further examinations were completed at 5 and 9 years for incident CHD. RESULTS: After 9 years, there was no increased risk of CHD associated with any Type A score. Nevertheless, high Bortner scores were associated with increased risk of incident CHD at 5 years and high JAS and Bortner scores were associated with a decreased risk between 5 and 9 years. Further analysis of Type A scores on time to first coronary event found strong inverse associations for all type A scores (JAS = 205 -0.49 months to first event, 95% CI = -0.20, -0.78, p =.001) (Bortner = 176 -0.27 months; 95% CI = -0.10, -0.44; p =.002) (Framingham = 0.44 -0.0011 months; 95% CI = -0.0002, -0.0019; p =.01). CONCLUSIONS: The data show Type A is a strong predictor of when incident coronary heart disease (or coronary event) will occur rather than if it will occur. These findings suggest that Type A increases exposure to potential triggers, rather than materially affecting the process of atherosclerosis.