Abstract
Objectives:
This study investigated whether anxiety characteristics independently predicted the onset of myocardial infarction (MI) over an average of 12.4 years and whether this relationship was independent of other psychologic variables and risk factors.

Background:
Although several psychosocial factors have been associated with risk for MI, anxiety has not been examined extensively. Earlier studies also rarely addressed whether the association between a psychologic variable and MI was specific and independent of other psychosocial correlates.

Methods:
Participants were 735 older men (mean age 60 years) without a history of coronary disease or diabetes at baseline from the Normative Aging Study. Anxiety characteristics were assessed with 4 scales (psychasthenia, social introversion, phobia, and manifest anxiety) and an overall anxiety factor derived from these scales.

Results:
Anxiety characteristics independently and prospectively predicted MI incidence after controlling for age, education, marital status, fasting glucose, body mass index, high-density lipoprotein cholesterol, and systolic blood pressure in proportional hazards models. The adjusted relative risk (95% confidence interval [CI]) of MI associated with each standard deviation increase in anxiety variable was 1.37 (95% CI 1.12 to 1.68) for psychasthenia, 1.31 (95% CI 1.05 to 1.63) for social introversion, 1.36 (95% CI 1.10 to 1.68) for phobia, 1.42 (95% CI 1.14 to 1.76) for manifest anxiety, and 1.43 (95% CI 1.17 to 1.75) for overall anxiety. These relationships remained significant after further adjusting for health behaviors (drinking, smoking, and caloric intake), medications for hypertension, high cholesterol, and diabetes during follow-up and additional psychologic variables (depression, type A behavior, hostility, anger, and negative emotion).

Conclusions:
Anxiety-prone dispositions appear to be a robust and independent risk factor of MI among older men (Fig 1).

Figure 1: Number of MI incidents at different anxiety levels. Figure shows number of myocardial infarction (MI) incidents among participants in each anxiety quartile (chi-square=9.21; degrees of freedom=3; p<0.05). (Reprinted from Shen B-J, Avivi YE, Todaro JF, et al. Anxiety characteristics independently and prospectively predict myocardial infarction in men: the unique contribution of anxiety among psychologic factors. J Am Coll Cardiol. 2008;51:113-119, with permission from the American College of Cardiology Foundation.)