Hostility and Coronary Artery Disease

Transcription

1 American Journal of Epidemiology Vol. 133, No. 2 Copyright C 1991 by The Johns Hopkins University School of Hygiene and Public Health Printed In U.S.A AO rights reserved Hostility and Coronary Artery Disease Dianne C. Helmer, David R. Ragland, and S. Leonard Syme Studies of the association between type A behavior and coronary heart disease have yielded inconsistent findings. A possible explanation for these inconsistent findings is that type A behavior is simply a marker for other behaviors that are truly related to coronary heart disease. Hostility is one such behavior that has been found in several recent studies to predict coronary heart disease and coronary atherosclerosis; however, several other studies have found null results. In the present study, the predictive power of hostility was tested in a study population of hospitalized men (n = 118) and women (n = 40) scheduled for coronary angiography. Potential coronary risk behaviors were assessed in the angiography patients and they were given the type A Structured Interview. Hostility was measured with the Cook-Medley Hostility Inventory and the Behavior Pattern Hostility Index, a measure of hostility derived from the type A Structured Interview. No significant positive associations were found for either Cook- Medley hostility or behavior pattern hostility and coronary occlusion. This was true whether hostility or coronary occlusion was treated as a dichotomous variable or as a continuous variable. In fact, most of trie observed associations were opposite to the predicted direction, although none was statistically significant. Replicating cutpoints of the Cook-Medley Hostility Inventory used in other studies that have reported positive associations with coronary heart disease also yielded null findings. The association between hostility and coronary occlusion was slightly modified by age and sex, but the interaction coefficients were not significant. The sample size yielded adequate statistical power to detect the hypothesized associations, and there was no evidence that selection bias, measurement error, or unexamined confounding accounted for the null findings. These results failed to confirm some earlier reports showing a positive association between hostility and coronary artery disease. Am J Epidemiol 1991 ;133: angiography; arteriosclerosis; coronary disease; hostility; risk factors; type A personality Positive associations in two prospective studies (1,2) made type A behavior a focus Received for publication May 5, 1989, and in final form July 27, From the School of Public Health, University of California, Berkeley, CA. Reprint requests to Dr David R Ragland, Department of BKxnedical and Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA This work was funded by the National Institutes of Health under grant nos. HL27143 and T32 HL The authors thank Dr. Margaret Chesney, Prevention Sciences Group, University of California, San Francisco, CA, and Dr. Redford Williams, Department of Psychiatry, Duke University Medical Center, Durham, NC, for their comments on an earlier draft of this paper. of interest in epidemiologic studies of coronary heart disease. Recent studies (3-7), however, have failed to confirm the previous results. Possible reasons for these inconsistent results include differences in sampling and measurement, temporal changes in the nature of type A behavior, and the declining rate of coronary heart disease in the United States (8). Another possible reason for the inconsistent results is that type A behavior may not itself be pathogenic, but instead may be a marker for other behaviors that truly convey risk for coronary heart disease. It is possible that methods for measuring type A behavior 112

2 Hostility and Coronary Artery Disease 113 (e.g., the Structured Interview) may not be sensitive enough to consistently measure such behaviors. Several authors (9, 10) have proposed that hostility may be such a behavior. Since 1980, at least 12 studies (9-20) have been reported on the association of some measure of hostility in relation to a coronary disease outcome, with somewhat mixed results. The first of these studies (9) reported a positive association between hostility measured by the Cook-Medley scale and coronary occlusion, but the analysis did not control for age and other cardiovascular risk factors. Two other early studies (10, 11) reported a significant positive association between Cook- Medley hostility and coronary disease incidence. However, three recent studies (14, 17, 18) reported no association between Cook-Medley hostility and coronary disease incidence. Several studies looked at hostility derived from a structured interview (12, 13, 15), and they reported significant positive associations between hostility and coronary occlusion (12, 13) and coronary disease occurrence (15). A re-analysis of type A interviews from the Multiple Risk Factor Intervention Trial (19) indicated a positive association between "potential for hostility" and coronary disease incidence, but the result was significant only when a one-tailed significance test was used. Two additional studies used other measures of hostility. One study (16) showed a positive association between self-reported hostility and coronary disease incidence among those with existing disease, but not among initially healthy individuals. Another study (20) reported no association between hostility measured by the Buss-Durkee Hostility Inventory and coronary occlusion. Using coronary angiography patients, the purpose of this study was to confirm or negate positive findings reported in previous studies. To maximize sensitivity for detecting hostility, we studied two measures of hostility: the Cook-Medley Hostility Inventory, a measure derived from the Minnesota Multiphasic Personality Inventory, and the Behavior Pattern Hostility Index, a measure derived from the type A Structured Interview. To determine whether hostility was differentially associated with alternative measures of coronary occlusion, we used two measures of disease: a dichotomous measure reflecting the presence or absence of coronary occlusion, and a continuous measure reflecting the total amount of coronary occlusion. MATERIALS AND METHODS Study population This study used data from a coronary angiography project conducted in six San Francisco Bay Area hospitals from Patients hospitalized because of angina, recent myocardial infarction, abnormal electrocardiogram, and/or treadmill tests, and who were scheduled for coronary angiography, were screened for possible recruitment into the study. Patients eligible for study were English-speaking, between 30 and 70 years old, and free of other major illnesses. Other eligibility criteria included no evidence of a myocardial infarction more than 6 months prior to enrollment and no previous angiography, angioplasty, or coronary artery bypass surgery. Of 182 eligible subjects, 161 volunteered for the study and were given the type A Structured Interview and asked to complete the study questionnaire prior to their angiography. Because two angiography films were lost and information was missing on both hostility measures for one subject, the study population for this report consisted of 158 subjects. Further details concerning the study population as well as the overall measurement of variables are given in a previous paper (21). Measurement of variables Hostility was measured by the Cook- Medley Hostility Inventory and the Behavior Pattern Hostility Index. The Cook- Medley Hostility Inventory is a subscale of the Minnesota Multiphasic Personality Inventory, and was originally designed to identify teacher aptitudes for classroom teaching (22). The subscale has acceptable reliability

3 114 Helmer et al. (10, 11, 22) and construct validity (23, 24). It is a self-administered test consisting of 50 true-false items; high scores on the inventory suggest attitudes and behaviors indicative of resentment, bitterness, cynicism, and mistrust of others. Scores were derived by summing the number of items marked in the direction of hostility. For most analyses, equivalent groups were obtained by dichotomizing Cook-Medley hostility at the median into low (<17.0) and high (>17.0) hostility groups. To provide greater power, analyses were also conducted using a continuous measure of this variable. The Behavior Pattern Hostility Index (15, 25, 26) was used to quantify hostility from audiotapes of the type A Structured Interview. It is the same measure used by Hecker et al. (15) in their study of participants in the Western Collaborative Group Study. Persons were trained to conduct the type A Structured Interview and use the Behavior Pattern Hostility Index in separate standardized courses, as directed by Rosenman (27) and Chesney et al. (25), respectively. The purpose of this index is to minimize the subjective and clinically-based judgements that have characterized other efforts to assess hostility derived from the type A Structured Interview (28, 29). To accomplish this, the Behavior Pattern Hostility Index quantifies specific and observable antagonistic and resentful behaviors that emerge during the interview. To use this index, the Structured Interview is divided into 20 key questions and subjects' responses to each question are rated for hostility according to the scoring criteria given in the Appendix table (15). Scores were obtained by summing the ratings obtained for each Structured Interview question. As with Cook-Medley hostility, behavior pattern hostility was dichotomized at the median into low (<4.0) and high (>4.0) hostility groups and was also analyzed as a continuous variable. The inter-rater reliability coefficient for 25 Structured Interview audio tapes randomly selected for reauditing by an independent assessor was highly significant (r = 0.77, p < 0.001). A measure of type A behavior was generated from the Structured Interview audio tapes, and several measures of social support were obtained from the self-report questionnaire administered to the patients. The correlation of hostility with both type A behavior and social support was quite low (i.e., for the Cook-Medley scale and type A/B behavior, r = 0.01, p = 0.90; for Cook-Medley and the Berkman social support index, r = -0.07, p = 0.37). Potential confounding coronary risk variables included in the multivariate risk models were: sex (male/female), age (years), income (<$10,000, $10,000-$19,000, $20,000-$29,000, $30, ,000, $40, ,000, >$50,000), history of hypertension (yes/no), serum cholesterol (mg/ dl), cigarette smoking (number of packyears), diabetes (yes/no), family history of coronary heart disease (yes/no), and angina (yes/no, according to the Rose Questionnaire (30)). Cholesterol components were not assessed in our study. Obesity, physical activity, and medication use were available on the data base, but were not correlated with either coronary heart disease or hostility and therefore were not included in the multivariate analyses. With the exception of serum cholesterol, data on these covariables were obtained from the study questionnaire and subjects' medical records. Serum cholesterol levels were obtained from the analyses of hospital blood samples by Bio- Science Laboratory, a research laboratory using standards set by the Centers for Disease Control. Angiographies were conducted according to procedures described by Sones and Shirey (31) and Judkins (32). The occlusion data were coded according to guidelines established by the American Heart Association (33). The four major coronary arteries (right, left main, left circumflex, and left anterior descending) were divided into 15 segments and each segment was observed for occlusions that were then rated as obstructing the artery by 25, 50, 75, 90, 99, or 100 percent. An independent rating of a 10 percent random sample of angiography films was highly correlated (r = 0.89, p = 0.001). Two measures of coronary occlusion were then constructed. Significant coronary oc-

4 Hostility and Coronary Artery Disease 115 elusion was defined as the presence of one occlusion obstructing a coronary artery by ^75 percent and was used for reasons of clinical relevance (significant vs. nonsignificant coronary occlusion). The mean occlusion score was calculated from the percent of each occlusion summed across the total set of observed occlusions and yielded greater statistical power for detecting significant associations between hostility and coronary disease. Statistical analyses Analyses of the two hostility variables were conducted on two overlapping subsets of the study population. Of the 158 subjects in the study group, six subjects were missing information on the Cook-Medley Hostility Inventory, leaving 152 subjects available for analyses. Additionally, of the 158 subjects, six different subjects were missing hostility data from the type A Structured Interview, leaving 152 subjects available for these analyses. The initial analyses described the rate of significant occlusion and the mean occlusion score for low and high levels of Cook- Medley and behavior pattern hostility. Multivariate logistic analyses summarized the associations between dichotomous and continuous measures of Cook-Medley and behavior pattern hostility and the rate of significant occlusion. These analyses yielded coefficients that represented the change in "logit of risk" per one level change in hostility (34). Using a linear model, multivariate regression analyses summarized associations between dichotomous and continuous measures of both Cook-Medley and behavior pattern hostility, and the mean occlusion score (35). Because the distribution of occlusion scores was skewed to the right, each score (x) was transformed (\n(x + 280)) to yield a variable that more closely met the "normality" assumption of the linear model. Analyses using this transformation yielded coefficients that represented the amount of change in "log coronary occlusion" per one level change in hostility. The antilog of the coefficient gives the change in the actual coronary occlusion score. Using the logistic and linear models, we also analyzed the association between Cook- Medley hostility and significant occlusion and mean occlusion score using cutpoints of the Cook-Medley hostility distribution used in three other studies (9-11). We replicated Williams et al.'s (9) dichotomous (<10 vs. >10) and six-level (0-10, 11-15, 16-20,21-25, 26-30, >30) cutpoints; Barefoot et al.'s (10) dichotomous (<13 vs. >13) and fourlevel (0-8, 9-13, 14-17, 18-31) cutpoints; and Shekelle et al.'s (11) five-level (0-8, 9-12, 13-17, 18-23, 24-44) cutpoints. These three groups not only replicated those used in the literature, but also represented a broad range of possible cutpoints. Our final analyses examined age and sex interactions with Cook-Medley and behavior pattern hostility in relation to significant occlusion and mean occlusion score. We constructed interaction terms treating age and hostility as dichotomous and continuous measures. For the dichotomous age-byhostility interaction terms, age was dichotomized at <50 years versus >50 years. The sex-by-hostility interaction terms also treated hostility as a dichotomous and continuous measure. RESULTS The study population (table 1) was composed primarily of middle-aged white males who were fairly evenly distributed across income and educational strata. A high proportion of subjects reported a history of hypertension, elevated serum cholesterol, cigarette smoking, coronary heart disease in their families, and angina. The rate of significant coronary occlusion and mean occlusion score for subjects with low and high levels of Cook-Medley and behavior pattern hostility are given in table 2. For both comparisons involving Cook- Medley hostility, the pattern of findings was opposite to the expected direction: the high hostility subjects had a lower rate of significant occlusion than the low hostility subjects

5 116 Helmeretal. TABLE 1. Demographics and selected coronary risk variables of 152 anglography patients, San Francisco, CA, Variable Sex Males Females Age (years) Income <$10,000 $10,000-$19,999 $20,000-$29,999 $30,000-$39,999 $40,000-$49,999 $50,000 Race White Hispanic Black Other Education <High school Some high school Completed high school Some college Completed college Graduate school History of hypertension* Yes No Serum cholesterol (mg/dl) > Cigarette smoking Ever smoked Never smoked Diabetes Yes No Family history of coronary heart disease Yes No Angina Yes No No % Systolic Wood pressure >140 mmhg or cflastofic Wood pressure >90 mmhg (75.9 percent vs percent) and a slightly lower mean occlusion score than the low hostility subjects (6.43 vs. 6.45). For behavior pattern hostility, the high hostility subjects had a slightly higher rate of significant occlusion than the low hostility subjects (74.3 percent vs percent) but their mean occlusion score was lower than the low hostility subjects (6.40 vs. 6.49). None of these differences was statistically significant. Table 3 gives the logistic and linear regression coefficients adjusted for other coronary risk factors and the corresponding 95 percent confidence intervals and p values for hostility and occlusion. Results are reported first for dichotomous Cook-Medley and behavior pattern hostility in relation to significant occlusion and mean occlusion score. For dichotomous Cook-Medley hostility and significant occlusion, the adjusted logistic coefficient was negative, that is, opposite to the predicted direction, but was not statistically significant (/S = -0.72, p = 0.10). Of the other three comparisons using dichotomous hostility measures, two were negative and one was positive, but none was statistically significant. Also shown in table 3 are results of the multivariate analyses using continuous hostility measures. All the adjusted coefficients were negative but none was statistically significant. In contrast to the hostility variables, sex predicted significant occlusion (p = 0.001) and sex, history of hypertension, and angina predicted mean occlusion score (p < 0.04). Compared with the logistic coefficients, a larger number of the regression coefficients were statistically significant, most likely because the mean occlusion score is a continuous variable that yielded greater statistical power. Table 4 shows results of the adjusted logistic and linear regression analyses replicating cutpoints of Cook-Medley hostility used in previous studies. Our first replication used cutpoints of Cook-Medley hostility used by Williams et al. (9) in their study of coronary angiography patients. As shown in table 4, there were no significant associations for hostility, treated either as a dichotomous or six-level variable, and significant occlusion or mean occlusion score. In contrast to Williams et al. (9), who reported that 70 percent of those subjects scoring >10 on the Cook- Medley Hostility Inventory had significant occlusion compared with 48 percent of those

6 Hostility and Coronary Artery Disease 117 TABLE 2. Rate of significant occlusion and mean occlusion score by dichotomous Cook-Medley and behavior pattern hostility in 152 angiography patients, San Francisco, CA, Cook-Medley hostility Low {n = 79) High (n = 73) Behavior pattern hostility Low (n = 78) High (n = 74) Rate of significant ocduston ( 75%) 75.9% (60) 71.2% (52) 73.1% (57) 74.3% (55) Mean occlusion score (togtransformed) TABLE 3. Adjusted coefficients (0), 95% confidence intervals (CIs), and p values for coronary occlusion by Cook-Medley and behavior pattern hostility in 152 angiography patients, San Francisco, CA, * Dichotomous hostility Cook-Medley Behavior pattern Continuous hostility Cook-Medley Behavior pattern Significant occlusion (==75%) 01 (95% Cl) ( ) 0.02 ( ) ( ) ( ) p value Mean occlusion score (log-transformed) 0t (95% Cl) ( ) ( ) ( ) ( ) p value Adjusted simultaneously for sex, age, income, history of hypertension, serum cholesterol, cigarette smoking, diabetes, famiy history of coronary heart disease, and angina 1 0 is the adjusted logistic coefficient for significant occlusion ( 75%). t 0 Is the adjusted linear regression coefficient for mean occlusion score (log-transformed). Coefficients for coronary occlusion by continuous hostility represent the difference In risk between the second and fourth quartile (interquartile range) TABLE 4. Adjusted coefficients (0) and p values for coronary occlusion by Cook-Medley hostility (replicating cutpolnts used In previous studies) in 152 angiography patients, San Francisco, CA, * Williams et al. (9) Dichotomous scale Six-level scale Barefoot et al. (12) Dichotomous scale Four-leveJ scale Shekelle et al. (13) Five-level scale Significant occlusion ( 75%) p value Mean occlusion score (log-transformed) 0t p value Adjusted simultaneously for sex, age, Income, history of hypertension, serum cholesterol, cigarette smoking, o3abetes, famiy history of coronary heart disease, and angina. 10 is the adjusted logistic coefficient for significant ocdusion ( 75%). % 0 Is the adjusted linear regression coefficient for mean occlusion score (log-transformed) shown). Consistent with the null findings from the Williams et al. (9) replication anal- yses, there were no significant associations between Barefoot et al.'s (10) dichotomous subjects scoring <10 (p = 0.02), we found that 76 percent of our study population scoring > 10 had significant occlusion compared with 69 percent scoring <10 (p = 0.42) (not

7 118 Helmeretal. scale or four-level scale or Shekelle et al.'s (II) five-level scale and coronary occlusion. Figure 1 shows the unadjusted relation of hostility and coronary occlusion stratified by age. For Cook-Medley hostility and significant occlusion, there was a slightly positive association among younger subjects (77.8 percent significant occlusion for high hostility subjects vs percent for low hostility subjects) and an inverse association among older subjects (69.1 percent significant occlusion for high hostility subjects vs percent for low hostility subjects). However, the logistic interaction coefficient representing this pattern of results was not statistically significant (/3 = -0.50, p = 0.58) (77 4) f 7,- 8 ) P = 0.58»t "" *" <76_5)\ (630) (6.29) (69.1) ~---^(6>3) ^,''(6.«) /8=-0.19 p= 0.35 A similar statistically nonsignificant pattern emerged for the comparisons of Cook- Medley hostility and mean occlusion score and for behavior pattern hostility and significant occlusion: in younger subjects, the hostility-coronary occlusion relation was positive and in older subjects, it was negative (/S = -0.19, p = 0.35 and 0 = -0.66, p = 0.48, respectively). For behavior pattern hostility and mean occlusion score, there was virtually no interaction with age (P = 0.07, p = 0.74). Figure 2 shows the unadjusted relation of hostility and coronary occlusion stratified by sex. In all cases, females showed an inverse association between hostility and cor- <50yeara (73 3)/ (82.4) (72-2) (71.9) (6J0) (645>v x ^~^ (6J1) /9 = p = 0.48 /9 = 0.07 p = Low High Low High Cook-Medley Hostility Behavior Pattern Hostility FIGURE 1. Significant coronary occlusion (>75%) and mean occlusion score (log-transformed) by Cook-Medley and behavior pattern hostility and age In 152 angiography patients, San Francisco, CA,

8 Hostility and Coronary Artery Disease 119 onary occlusion compared with males, who showed no consistent pattern of results. When the interactions for age and sex were examined in a multivariate model, the results were consistent with the univariate finding. DISCUSSION "I (833) (64.0) \ \ \ \ \ (6-51) (632) \ \ \ \ \ \ N (763) \<50 0) (6J1) P = P = In this study, no evidence was found for a positive association between hostility measured from the Cook-Medley Hostility Inventory or the Behavior Pattern Hostility Index and coronary occlusion. Treating the hostility variables and coronary occlusion variable as dichotomous or continuous measures did not differentially alter study findings. Adjusting for possible confounding variables did not change the results. Analyses using cutpoints of the Cook-Medley Hostility Inventory reported in other studies also failed to show an association between hostility and coronary occlusion. Results of interaction analyses incorporating Cook- Medley hostility and age yielded small interaction coefficients suggesting that the association between hostility and coronary occlusion may be influenced by age but these coefficients were not statistically significant. Results also showed minimal interactions between hostility and sex that were not statistically significant. Females Mala ( s 76.4) (65 J2) (6J1) * (817) V \(42.9) (6.48) /3 = p= = -O.15 p = 0.45? o (6J9) \ \ \ Low High Low High Cook-Medley Hostility Behavior Pattem Hostility FIGURE 2. Significant coronary occlusion ( 75%) and mean occlusion score (tog-transformed) by Cook-Medley and behavior pattern hostility and sex in 152 angiography patients, San Francisco, CA,

9 120 Helmer et al. There were several possible explanations for our null findings: I) bias introduced through selection of subjects; 2) bias in the measurement of study variables; 3) inadequate statistical power, 4) masking by unexamined confounders; 5) use of an extreme population (i.e., angiography patients); 6) the absence of a true association between hostility and coronary occlusion. The first two sources of potential bias are especially important because this study was cross-sectional rather than prospective. Bias introduced through selection of subjects was the first possible reason for our null findings (36, 37). The association between hostility and coronary occlusion might be underestimated if those patients with high hostility were "overselected" for angiography. However, there was no compelling reason to believe that patients with high hostility were overselected in our study and not similarly overselected in other angiography studies that reported positive associations between hostility and coronary disease. Bias in the measurement of study variables was the second possible explanation for the null findings. Several steps were taken to minimize this bias: I) patients were excluded who had a myocardial infarction more than 6 months prior to angiography or who had previous angiography, angioplasty, or coronary artery bypass surgery; 2) the study questionnaire was designed to obtain information on subjects' risk behaviors prior to the onset of coronary symptoms; and 3) subjects were interviewed prior to angiography. The third possible explanation was inadequate statistical power. We calculated the statistical power in this study for detecting various degrees of "true" association between dichotomous hostility (low vs. high) and dichotomous coronary occlusion (significant vs. nonsignificant occlusion). Given the overall rate of significant coronary occlusion (74.0 percent) and the number of subjects used in these analyses {n = 152), the statistical power was quite adequate. For example, the power to detect a "true" risk ratio of 1.5 (i.e., a rate of approximately 0.89 vs. 0.59) was The power to detect a "true" risk ratio of 1.3 (i.e., a rate of approximately 0.84 vs. 0.64) was 0.72 (38). Because the other comparisons used a continuous occlusion measure and/or a continuous hostility measure, these had even greater power. Inadequate statistical power did not seem to be an issue in our null findings. Further, the study hypothesis was that hostility was positively associated with coronary occlusion. However, most of our results were inverse, indicating that a substantial positive association was unlikely. For example, the 95 percent confidence interval for dichotomous Cook-Medley hostility and significant coronary occlusion was 1.58 to 0.14; this indicated that the "true" association in our study was not likely to be above a risk ratio of about 1.03 (a rate of 0.76 vs. 0.74). It is worth noting that some angiography studies showing positive results for hostility and coronary disease have had relatively small study groups. The study by Williams et al. (9) («= 424) had a larger number of subjects than the present study, but both Dembroski et al. (12) (/i = 131) and Mac- Dougall et al. (13) (n = 125) had fewer subjects than the current study. The fourth possible explanation for our null findings was the presence of an unexamined confounder that masked the true association between hostility and coronary occlusion. However, after adjustment for nine potentially confounding coronary risk variables, the adjusted results did not markedly differ from the unadjusted results. Confounding by any other unmeasured coronary risk variable seemed unlikely. The fifth consideration is that angiography patients comprise a fairly extreme group in terms of cardiovascular risk. It is possible that there is insufficient variation in an extreme population to detect an association. However, several studies of hostility and coronary artery disease that have reported a positive association have used angiography populations (9, 12, 13), and there is no indication that the population used in the present study is substantially more extreme than the populations used in these other studies.

10 Hostility and Coronary Artery Disease 121 None of these explanations for our null findings seems likely. We have concluded that in this study group there was no indication of a true overall association between hostility and coronary occlusion. Studying different measures of hostility in relation to two measures of coronary occlusion further increased our confidence that there was no significant positive association between hostility and coronary occlusion. Although there seemed to be no overall association, it is possible that there were associations in some age and sex subgroup analyses (R. B. Williams, personal communication, 1988). Recent reports have suggested that the association between behavioral variables and coronary occlusion may be modified by age (19, 39) and sex (39, 40). Results from the interaction analyses suggested some small but nonsignificant interactions for hostility and age that consisted of an inverse association in the older group and a small positive association in the younger group. Our results also indicated small but nonsignificant interactions of hostility with sex, with females showing a consistently inverse association between hostility and coronary occlusion and males showing no consistent pattern of results. Implications As null findings have accumulated for type A behavior and coronary heart disease, the psychologic construct of hostility has emerged as a major alternative hypothesis. The identification of hostility as a possible risk behavior for coronary artery disease and myocardial infarction is important because it may possibly explain the inconsistent results in past studies of type A behavior and coronary heart disease; measures for type A behavior may not be sensitive enough to consistently identify the hostility component of the behavior pattern. The findings to date have been encouraging. However, hypothesis testing in etiologic research requires that findings be confirmed using other populations and settings. Our failure to confirm other positive results (9-13, 15, 16, 18), coupled with other null findings (14, 16, 17, 18, 20), indicates that hostility is not a consistent predictor across different studies, even when the study populations and/or methods are similar. Ideally, results across studies should converge toward a consistent picture. The absence of convergence in this area of research indicates the need for caution in drawing broad conclusions from the results of individual studies. References 1. Rosenman RH, Brand RJ, Jenkins CD, et al. Coronary heart disease in the Western Collaborative Group Study: final follow-up experience of 8V2 years. JAMA 1975:233: Haynes SG, Feinleib M, Kannel WB. The relationship of psychosocial factors to coronary heart disease in the Framingham Study. III. Eight-year incidence of coronary heart disease. Am J Epidemiol 1980;lll: Ruberman W, Weinblatt E, Goldbert JD, et al. Psychosocial influences on mortality after myocardial infarction. N Engl J Med 1984,311: Case RB, Heller SS, Case NB, et al. Type A behavior and survival after acute myocardial infarction. N Engl J Med 1985;312: Shekelle RB, Hulley SB, Neaton JD, et al. The MRFIT behavior pattern study. II. Type A behavior and incidence of coronary heart disease. Am J Epidemiol 1985; 122: Ragland DR, Brand RJ. Coronary heart disease mortality in the Western Collaborative Group Study: follow-up experience of 22 years. Am J Epidemiol 1988; 127: Ragland DR, Brand RJ. Type A behavior and mortality from coronary heart disease. N Engl J Med 1988;318: National Heart, Lung, and Blood Institute. Type A behavior, anger, and hostility: working group summary. In: Ostfeld AM, Eaker ED, eds. Psychosocial variables in epidemiologic studies of cardiovascular disease. Proceedings of a workshop. Bethesda, MD: National Institutes of Health, 1985: (N1H publication no ). 9. Williams RB, Haney TL, Lee JCL, et al. Type A behavior, hostility, and coronary atherosclerosis. Psychosom Med 1980;42: Barefoot JC, Dahlstrom WG, Williams RB. Hostility, coronary heart disease incidence, and total mortality: a 25-year follow-up study of 255 physicians. Psychosom Med 1983;45: Shekelle RB, Gale M, Ostfeld AM, et al. Hostility, risk of coronary heart disease, and mortality. Psychosom Med 1983;45: Dembroski TM, MacDougall JM, Williams RB, et al. Components of Type A, hostility, and anger-in: relationship to angiographic findings. Psychosom Med 1985:47: MacDougall JM, Dembroski TM, Dimsdale JE, et al. Components of Type A, hostility and anger-in:

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