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Stress and coronary heart disease in three field studies
J. ckron. Dis. 1964, Vol. 17, pp. 73-84. Pergamon Press Ltd. Printed in Great Britain
STRESS AND CORONARY THREE
FIELD
HEART
DISEASE
IN
STUDIES*
WALTER I. WARDWELL?,MERTONHYMANand CLAUS B. BAHNSON University
of Connecticut,
(Received THE
15
ASSESSMENT
January
Storrs, Conk 1963)
OF
STRESS
THE PURPOSEof this paper is to compare the findings from three separate field studies relating social background variables to the incidence of coronary heart disease. Although each of the studies is limited in scope, the similarity in their findings is sufficiently impressive to justify the formulation of tentative hypotheses implicating such variables as immigrant generation, urban or rural childhood background, socio-economic level, and degree of involvement in the predominant Protestant, Anglo-Saxon culture. Although there are presumably several intervening variables between such environmental characteristics and the pathogenic physiological processes involved in coronary heart disease, these more distant relationships may serve as indices or clues to significant factors in the etiology of this prevalent and puzzling disease. Specifically. it may make possible identification of sources of chronic stress potentially related to the onset of coronary heart attacks. The idea that stress of some kind is involved in the etiology of coronary heart attacks has long been popular among laymen, if not among many of the scientists studying heart disease. However, the concept stress is very difficult to deal with since it has so many different meanings. For some researchers it refers to aspects of the environment causing upheaval in the organism (e.g., noxious gases, infectious agents, work deadlines), while for others it refers to the reaction within the organism itself to such environmental conditions [l]. Then, too, workers in different disciplines formulate different conceptions of what is stressful. Heavy labor and long hours of work are phenomena of a quite different order from the heartbreaking loss of a loved one, the crushing disappointment of a life-long ambition, anxiety over financial problems, or the chronic irritation caused by an insufferable wife or employer. Each of these ‘stressors’ produces a different type of impact on the organism. Furthermore, the time span of stress can vary from a single episode to long-standing chronic stresses. On the one hand, a single traumatic event that causes a strong emotional reaction in the individual (e.g., anger or fear) may, through sympathetic-adrenal pathways, result in occlusive arterial spasm or thrombus formation; while on the other hand. ischemic heart disease may develop more gradually from a longstanding atherosclerotic process (possibly related to disturbed lipid metabolism) which has so severely narrowed the lumen of the coronary artery that a sudden *This research has been supported
by Grants H-4257 and H-6889 of the National Institutes of Health, and the Heart Disease Control Program of the U.S. Public Health Service. TAddress for reprints: Dr. Walter I. Wardwell, Associate Professor of Sociology, University of Connecticut, Storrs, Connecticut. 73
74
WALTERI. WARDWELL,MERTONHYMAN and CLAUS B. BAHNSON
demand on the heart muscle may quickly deplete the necessary blood supply and thus produce an infarct. Until the physiological mechanisms underlying the slow process of atherogenesis and the dramatic suddenness of thrombotic occlusion are well understood, it is unreasonable to expect the social scientist to explicate the intervening variables between such pathological processes and different kinds of stress. However, it seems reasonable to hypothesize that there may be a relationship between the different pathologies and different kinds of stress, for there is overwhelming evidence from the field of physiological psychology and psychosomatic medicine that cardiovascular functioning is related differentially to different emotional states of the psychobiological organism [2-81. There is also a well established body of literature attesting to wide variations in behavior, habits, and emotions between people from different societies or cultures (quite apart from inherited biological differences) in addition to individual differences within such groups. The sociologist and the social anthropologist delineate variations between broad groupings of people (e.g., by sex, age, nationality, class level, occupation) rather than between individuals as such, a procedure thoroughly familiar to the epidemiologist. As a technique for studying stress this approach offers some advantages over that of psychology, since the type of information required is easier to elicit than are personality data, and since less distortion is likely to occur with sociological variables (e.g., nationality, occupation) than with such psychological variables as sentiments and values when both are gathered retrospectively 191. Sociologists have long concerned themselves with the stressful impact on the individual of social conditions such as culture conflict and situational pressures. PARK’s ‘marginal man’ IlO] is probably the best known of the concepts referring to the effect of conflicts in the socio-cultural environment (see also ST~NEQUIST [ll]). DURKHEXM’Sterm Anomie [12] has come to be applied generically to all situations involving value conflict and confusion over role-definitions 1131. Where a person is second-generation (i.e., of immigrant parents) or where his parents are of differing ethnic or religious backgrounds, the individual experiences the anemic situation over many years, perhaps a whole lifetime. The impact on his personality is likely to be extensive, influencing such basic psychological characteristics as selfconcept, and mode of impulse regulation and ego defenses. PARSONS has applied the phrase ‘socially structured strain’ to situations-like that of the marginal man-which would be stressful for any person experiencing them [14]. COlTRELL formulates a number of propositions concerning roleadjustment (i.e., stress-reduction) as a function of the degree of clarity and specificity with which a role is defined, especially “the proportion of the social situations . . . for which there are explicit definitions of the reciprocal behavior expected”: lack of clarity in role definition results in “tension, anxiety, and frustration generated by the attempt to discover and play a given role” 1151. GOODE emphasizes that a wide range of role opportunities and choices adds to ‘role strain’ ‘[16-J. It is characteristic of tradition-oriented groups (e.g., those dominated by old-world cultures, rural mores, and authoritarian controls) that the number of role choices is smaller and roles tend to be less ambiguously defined than in nontradition-oriented groups. In general, a child socialized in such an environment
Stress and Coronary
Heart Disease in Three Field Studies
75
learns with less confusion the behaviour patterns expected of him and probably experiences little conflict concerning these fixed roles. By contrast, the ambiguous standards and requirements of a non-traditional environment may often burden the person for the rest of his life since many situations must be constantly re-valued and differentially responded to, quite apart from the additional stresses which may be imposed upon him by new environmental demands. DURKHEIMmade a second major contribution to the understanding of personality stress from a sociological point of view in his analysis of what he called egoismthe excessive individualism and mandatory personal autonomy historically associated with Protestantism. The Protestant, who, in Rousseau’s famous phrase, is ‘forced to be free’, bears a heavy load of responsibility for his actions and his fate. The resulting ‘cult of the individual’ has been a source of socially structured strain not only for Protestants, but for all those who have internalized the values of the ‘Protestant ethic’, which, in MAX WEBER’Sanalysis [17], is psychologically quite similar to DURKHEIM’Streatment of egoism and the cult of the individual. The fact that DURKHEIMcorrelated both egoism and Anomie with high suicide rates testifies to their close association with personality stress in his own thinking as well as in his data. The social scientist can determine to what extent such social characteristics believed to be stressful are associated with clinical coronary heart disease in a population. This certainly is a de-personalized way of dealing with the problem of stress which leaves out, or open to speculation, the role of possible intervening psychoIogica1 variables as well as the potentially independent, or interdependent, roles played by such physiological variables as diet, obesity, smoking, physical exercise, or inherited cardiovascular weakness. However, logically such physiological variables can be controlled for or studied in interaction with social and psychological variables, provided enough cases are assessed for each of the subgroups involved. An approximation to this is built into a retrospective study of myocardial infarction currently being carried on by W. I. WARDWELLand C. B. BAHNSONin southeastern Connecticut. In the present paper there is unfortunately insufficient space to present detailed tables showing the effect of diet, obesity, heredity, blood pressure, and smoking for each of the three studies independently and in interaction with the social background variables.* It should be emphasized, however, that when these physiological variables are introduced as controls, the effects of the social variables remain intact. THE
THREE
STUDIES
The first of the three studies we report on is, chronologically speaking, the North Dakota Heart Study, initiated in 1956 by the Heart Disease Control Program of the United States Public Health Service [IS, 191. In this study a special casereporting system was set up in cooperation with the physicians of six predominantly rural counties in North Dakota. These counties were selected in part because North Dakota has one of the lowest coronary heart disease mortality rates in the nation. A 30-min interview schedule was administered to each white male aged 35 and over (n =203) who had survived some manifestation of coronary heart *The
variables are discussed in the three separate studies [18-231.
76
WALTER I. WARDWELL, MERTQN HYMAN and CLAUS B. BAHNSON
disease, and also to a double sized (i.e., n= 406) comparison group of white males matched for age who were randomly selected by area1 sampling from the total population of the counties (excluding persons who had experienced some form of coronary heart disease). The second study is the Middlesex County Heart Study in Connecticut, which was begun in 1957 in conjunction with the Connecticut Department of Health [20-221. Two phases of this study are relevant here-one permitting comparison of heart patients with a group of persons suffering a different serious illness, the other permitting comparison with a ‘normal’ population. As in the North Dakota Study the subjects were all white males, but the heart patients in the Middlesex Study were limited to those aged 35-64 who had been medically diagnosed as having their first myocardial infarction. In the first phase of the Middlesex Study all white males aged 35-64 residing in the County who were diagnosed during a one-year period as having the first myocardial infarction (n= 32) were interviewed in their homes for an average of 3.6 hours, as were an equal number of age-matched white males from the same geographical area who were hospitalized during the same period for a lifethreatening or potentially disability-producing illness, but who were judged, on the basis of their medical history and electrocardiographic record, to be free of coronary artery disease. In the second phase of the study, all Middlesex County white males aged 35-64 diagnosed in a one and one-half year period as suffering their first myocardial infarction or as having died from a first coronary attack (n=87) were compared with an age-matched group of white males five times as large (n=435), randomly selected by area1 sampling from the total population of Middlesex County (excluding actual or probable cases of coronary heart disease). Data for this comparison were gathered using a slightly modified version of the interview schedule from the North Dakota Heart Study, information concerning deceased heart patients being obtained from the nearest surviving relative. Thus two sets of comparisons can be made from the Middlesex County data-one with a sick comparison group and one with a well comparison group. It should be noted that the coronary patients in the first phase of the Middlesex County Study comprise part of those studied in the second phase. The third study we are reporting on is much more limited than the other two, since the number of coronary cases is very small (n = 16) and since the data were originally gathered for a quite different purpose in the ‘Midtown Manhattan Study of Mental Disorders’ conducted from 1952 to 1961 by the Cornell Program in Social Psychiatry, Cornell University Medical College [23]. Through the courtesy of the directors of the study, and with the assistance of the physicians and hospitals of respondents who had indicated that they had ‘a heart condition’. we identified 16 cases of ‘arteriosclerotic coronary heart disease’ among the white males aged 40-60 included in the study. These cases were compared with two age-matched random samples of white males from the total interviewed in the Cornell Study (which selected respondents initially by 3-stage area1 probability sampling from a ‘gold coast to slum’ section of Manhattan). The first comparison group was eight times as large (M= 128) as the coronary group and consisted entirely of those free of any kind of heart condition, including hypertension (according to responses made during interviewing): the second group, eleven times as large (n= 176), was a random
Stress and Coronary
77
Heart Disease in Three Field Studies
sample of the total population interviewed (not excluding those who stated that they had a heart condition). The three studies thus represent a continuum from rural to highly urban environments. RESULTS
AND
DISCUSSION
The results from the three studies are presented in detail in Tables l-3 and are summarized in Table 4. In Tables l-3 the number of coronary and non-coronary cases, and the ratio of observed to expected cases of coronary artery disease, are shown for certain social background variables. In each case the ratio is determined by dividing the number of coronary cases in a particular category by the number of control cases in that category, adjusted for the difference between the total number of coronary and control cases in that study. In Table 4 only the ratios of observed to expected cases are shown. The social background variables selected clearly antedate the illness and thus could not have been affected by the experience of having had the illness: nor is recall of such variables likely to have been different for the coronary and non-coronary subjects studied. TABLET.
NORTHDAKOTAHEARTSTUDY
Ratios of observed to expected cases of coronary heart disease in white males aged 35 and over in six North Dakota counties, based on a comparison between 203 such cases and an age-matched probability sample of 406 ‘well’ (i.e., exclusive of actual or probable cases of CHD) persons resident in those counties.
Number of cases Immigrant generation 1st : Respondent and parents European-born 2nd : Both parents European-born 2nd: Father European, mother American 2nd: Father American, mother European 3rd or later: Both parents born in U.S. Occupational level of father Agricultural Non-agricultural Manual White collar Occupational level of respondent Agricultural Non-agricultural Manual White collar
CHD
‘Well
203
406
26 50 20 15 80
72 143 51 24 104
0.72 0.70 0.78 1.25 1.54
129
294
0.88
38 22
57 33
1.33 1.33
104
246
0.85
46 51
98 56
0.93 1.82
Ratio
We have chosen to report on relatively ‘objective’ items hypothesized to be related to emancipation from tradition-orientation, exposure to culture conflict, anomie and egoism. The indicators of tradition-orientation are: being first generation (i.e., born overseas), having a rural upbringing, being Catholic or having Catholic parents, being of Southern European, Eastern European, or FrenchCanadian stock, and being of a relatively lower occupational level. It is clear that the incidence rates are very low for persons in each of these categories. (One
WALTER I. WARDWELL, MERTOIVHYMAN and CLAUS B. BAHNSON
18
TABLE 2. MIDDLESEX COLJNTY HEARTSTLJDY
Ratios of observed cases ofmyocardialinfarction to expected cases, based on two types of comparison: (1) 32 surviving primary myocardial infarctions occurring in residents of Middlesex County during a one-year period compared with a series of 32 age-matched hospitalized persons free of coronary heart disease; and (2) 87 surviving and non-surviving primary myocardial infarctions occurring in residents of Middlesex County during a period of a year and a half compared with an age-matched probability sample of 435 ‘well’ (i.e., exclusive of actual or probable cases of myocardial infarction) persons residNon-whites, females, and persons under 35 years or over 64 years are ent in Middlesex County. excluded from both comparisons. M.T.
Other sick Ratio
435 ___-
J
0.50 0.92 1.67* 1.29
12 23 10 39
78 142 38 168
0.77 0.81 1.32 1.16
9 18 1 3
19 6 3 3
0.47 3.00 0.33* 1.00*
20 45 5 10
198
0.51
Religion of respondent Catholic Protestant Jewish
11 20 1
19 10 3
0.58 2.00 0.33*
Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European
7 23
15 14
Childhood Rural Urban
6 26
Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant,
1 Catholic)
32
5 12 5 9
10 13 3
‘Well’ Ratio
87
Number of cases __Immigrant generation 1st : Respondent and parents European-born 2nd: Both parents European-born 2nd: One parent European-born 3rd or later: Both parents born in U.S.
32
M.I.
177
1.27
19 21
1.32 2.38
28 52 4
213 194 18
0.66 1.34 1.11
0.47 1.64
20 64
157 258
0.64 1.24
9 23
0.67 1.13
19 67
138 296
0.69 1.13
11 21
15 16
0.73 1.31
48 32
314 114
0.76 1.40
12 20
20 12
0.60 1.67
56 31
298 96
0.94 1.66
environment
Occupational Lower Higher
level of father
Occupational Lower Higher
level of respondent
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
possible exception, the farm-born migrants to New York City, is discussed below.) Much higher rates are found for persons emancipated from tradition-orientation and for those experiencing cultural heterogeneity and varying degrees of anomie: secondor later-generation Americans (in particular those with one parent American-born and the other foreign-born), persons with an urban upbringing, those whose parents are of different religions, people of Old Yankee or Northwestern European stock, and those who were of or have achieved a relatively high occupational level. In the Midtown Manhattan Study and in the ‘other sick
Stress and Coronary TABLE
3.
79
Heart Disease in Three Field Studies MIDTOWN
MANHATTAN STUDY
Ratios of observed to expected cases of ‘arteriosclerotic coronary heart disease’ in white males aged 4&60 in the Cornell University Medical College’s, Midtown Manhatten study, based on comparisons between 16 such cases and an age-matched random sample of 128 ‘well’ (i.e., free of any kind of heart condition, including hypertension) persons; and with an age-matched random sample of 176 persons (including those with heart conditions) selected from the total interviewed. CHD
‘Well’
16
128
6 5 2 3
67 27 7 27
0.72 1.48 2.29* 0.88*
96 41 8 30
0.69 1.34 2.15* 1.10*
4 10 0 1
40 47 23 11
0.80* 1.70 o.oo* 0.73*
60 71 19 21
0.73* 1.55 o.oo* 0.52*
4 9 0
47 46 18
0.68* 1.57 o.oo*
61 70 15
0.72* 1.41 o.oo*
3 12
42 69
0.57* 1.40
58 98
0.57* 1.35
Childhood environment Farm Village, town, city City over 500,000 (other than N.Y.C.) New York City
4 4 0 8
14 59 24 30
2.28* 0.54* o.oo* 2.13
17 72 39 47
2.59* 0.61* o.oo* 1.87 _
Occupational Lower Higher
level of father 9 7
69 59
1.04 0.95
101 14
0.98
Occupational Lower Higher
level of respondent 5 11
65 61
0.62 1.44
94 80
0.58 1.51
Number of cases Immigrant generation 1st: Respondent and parents European-born 2nd: Both parents European-born 2nd: One parent European-born 3rd or later: Both parents born in U.S. Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant,
1 Catholic)
Religion of respondent Catholic Protestant Jewish Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European
Ratio
Normal
Ratio
176
1.05
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
comparison group of the Middlesex County Study the number of subjects of religiously intermixed parentage is probably too small to be reliable, but the ‘well’ comparison in the latter study provides a reliable result in the predicted direction. In general there is a reassuring consistency among the findings from the three studies (including two different comparison groups in the Middlesex County Study). The differences among the three sets of results appear to us to be relatively minor and to be comprehensible in view of the different locales in which they were conducted. The fact that the published epidemiological literature on coronary heart
80
WALTER I. WARDWELL, MERTON HYMAN
TABLET.
SUMMARY
and CLATJS B. BAHNSON
OF THE THREE STUDIES
Summary of ratios of observed to expected cases of myocardial infarction or arteriosclerotic heart disease in the Middlesex County, Midtown Manhattan, and North Dakota studies. North Dakota
Type of comparison group Number of experimental cases Number of comparison cases Immigrant generation 1st : Respondent and parents European-born 2nd: Both parents European-born 2nd : One parent European-born 3rd or later: Both parents born in U.S. Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant, 1 Catholic) Religion of respondent Catholic Protestant Jewish Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European Childhood environment Rural Urban Farm Village, town, city City over 500,000 (other than N.Y.C.) New York City Occupational level of father Lower Higher Occupational Lower Higher
Middlesex County
coronary
Midtown Manhattan
‘Well’
Other sick
‘Well’
‘Well’
Normal
203 406
32 32
87 43.5
16 128
16 176
0.72 0.70 0.93 1.54
0.50 0.92 1.67* 1.29
0.77 0.81 1.32 1.16
0.72 1.48 2.29* O.&S*
0.69 1.34 2.75* 1.10*
-
0.47 3.00 0.33*
1.oo*
0.51 1.27 1.32 2.38
0.80* 1.70 o.oo* 0.73*
0.73* 1.55 o.oo* 0.52*
-
0.58 2.00 0.33*
0.66 1.34 1.11
0.68* 1.57 o.oo*
0.72* 1.41 o.oo*
-
0.47 1.64
0.64 1.24
0.57* 1.40
0.57* 1.35 -
0.88 1.33 -
0.67 1.13 -
0.69 1.13 -
2.28* 0.54* o.oo* 2.13
2.59* 0.61* o.oo* 1.87
0.95 1.33
0.73 1.31
0.76 1.40
1.04 0.95
0.98 1.05
0.87 1.82
0.60 1.67
0.94 1.66
0.62 1.44
0.58 1.51
level of respondent
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
disease presents a somewhat inconsistent picture in regard to some of the variables reported here provides a setting for discussing the results of the three studies. For example, DAWBER and his co-workers in a preliminary report from the projected 20-year Framingham Heart Study cite a coronary heart disease rate for their foreign-born subjects higher than that for their native-born subjects [24],
Stress and Coronary Heart Disease in Three Field Studies
81
while STAMLERfound in a study of the male labor force of a Chicago utility corporation that the incidence rate of new coronary heart disease for native-born skilled workers and foremen was three times the rate for foreign-born workers in these categories [25]. In the three studies we are reporting, the lowest rates of coronary heart disease are found among the foreign-born, with much higher rates found among native-born subjects, whether in the second or later generations. The next to lowest rates are found, in the Middlesex and North Dakota studies, among those of the second generation with both parents born in Europe, whereas those of the second generation with one parent born in Europe and the other in the United States reveal the highest coronary heart disease rates of all (except for the third generation in the North Dakota Study). The explanation may be that culture conflict is greater where represented within the parental family than when experienced only outside the family. Similarly, the higher rate among North Dakota respondents if the father, rather than the mother, is the American-born parent may be associated with unusual stress in the child’s reorientation from an early motherrelationship to a later father-relationship, which in the case of a European-born mother and an American-born father would be most sudden and abrupt. Although religious differences in the incidence of coronary heart disease go unmentioned in the literature, religion is clearly a significant variable in the present report. In the studies where data are available the ratio of observed to expected cases among Protestants, whether based on the respondent’s reported religion or that of his parents, is 2-7 times that among Catholics. Moreover, the incidence for Protestants is equally high in all generations; though Catholics attain their highest rate in the second generation, even there it is only half the Protestant rate. The figure for Jews may be unreliable because of small numbers, but it is worth noting that the statistically most acceptable ratio (that for the ‘well’ comparison group in Middlesex County, based on 87 coronary and 435 ‘well’ cases) reveals a Jewish rate approximately the same as that for Protestants. Few epidemiological studies report on ethnic differences associated with coronary heart disease within the same community. Although DAWBERdiscovered no differences in the Framingham Study [24], EPSTEIN found that Jewish clothing workers in New York City had a rate twice as high as that of Italian clothing workers [26]. Variations among ethnic groups in the present studies, it should be noted, conform to the general pattern for coronary heart disease mortality rates in Europe, where higher rates are found in the Northwestern European countries and lower rates in the Eastern and Southern European countries 1271. For the United States there is a well-established geographic pattern of mortality from coronary heart disease-namely, that age-adjusted death rates are far higher in the urban and industrial areas than in rural areas ‘[28, 291. BRESLOWand BUELL report that farmers and farm laborers have a much lower mortality rate from arteriosclerotic and coronary heart disease than do non-farmers, even when the latter are engaged in heavy physical activity ‘[30]. If such differences are related to life style it would seem likely that within most population groups there would be a difference between those reared in urban versus those reared in rural areas. In the Middlesex County Study this comparison is based on responses to the question: “Did you ever live on a farm for as much as 5 years at a time before you were 18 years old?“, while in the North Dakota Study the data indicate whether the
82
WALTER I. WARDWJXL, MERTON HYMAN and CLAUSB. BAHNSON
respondent’s father was in agricultural or non-agricultural employment. In both of these studies the ratio of observed to expected cases of heart disease is nearly twice as great among the city-reared; but in the Midtown Manhattan Study in New York City, on the other hand, those reared on a farm appear to have the highest rate of all, if we can place confidence in the small number of cases. In the latter instance the explanation may involve a completely different interacting variable not measurable in the other two studies-that of the stressful effects of migration from a farm to a metropolis, and the resulting cultural discontinuity involved. Occupational level is used as an index of socio-economic status. Like the items already discussed, father’s occupational level is clearly antecedent to the development of coronary heart disease in the son and therefore could logically stand in some kind of causal relationship to it or be an index of some other variable that does so. The patient’s own occupational level, on the other hand-though existing prior to the clinical manifestation of coronary artery disease-does not necessarily precede all the other variables potentially involved in its etiology, for both the disease and occupational choice could logically result from some third variablefor example, personality type. The published literature contains frequent reference to the social class level of persons with coronary heart disease, without consistent tidings. DAWBER[24], KENT et al. [31], and STAMLER[32] find that coronary heart disease rates are lower for persons at the higher socio-economic levels, while LEE and SCHNEIDER[33], LOGAN1341, and STAMLERhimself in another study [25] report opposite findings consonant with the three studies reported here, in which the coronary subjects are more likely to have come from and to have achieved a relatively higher occupational level.
SUMMARY
AND
CONCLUSION
Differences found in the three studies according to occupational level, rural-urban background, ethnic background, religion, and generation all overlap each other, but it is not feasible to present tables showing the effect of each. In Connecticut the variables carrying the greatest weight when other variables are controlled are religious affiliation and occupation. On the other hand, in North Dakota, where religion was not studied and, due to the relatively small number of Catholics in the state, would probably not constitute as significant a source of variation as it does in Connecticut, the key variables when other variables are controlled are immigrant generation and urban-rural background. In Connecticut, where coronary mortality rates are high in general, the exceptionally low cell in a two-by-two table relating religion and occupation is that for Catholics whose fathers were in low status occupations. In North Dakota, where rates are low in general, the exceptionally high cell in the two-by-two table relating urban-rural background and immigrant generation is that for the sons of American. born fathers in urban occupations. In the predominantly farming area of North Dakota the more important socio-economic distinction is between those whose fathers were farmers and those whose fathers were not; while in Connecticut, where few of the respondents were raised on a farm and where the economy is industrialized, the important socio-economic distinction concerns occupational level. In both cases the more vulnerable subjects are those who are closest to the American
Stress and Coronary
Heart Disease in Three Field Studies
83
urban middle class Protestant ethos. The findings from the Midtown Manhattan Study are compatible. Examination of the personality characteristics of coronary heart disease patients is beyond the scope of this paper; furthermore, such an exploration is not feasible for certain of these studies, due to limitations in the types of data gathered. However, intensive study of personality factors in the coronary and sick control comparison groups of the Middlesex County Study and in the Midtown Manhattan Study reveals tendencies among coronary cases toward particular personality stresses consonant with the sociological findings we report here (cf. [35]). The idea that stress may be resolved via a psychosomatic discharge route as an alternative to psychological disorganization is gaining scientific acceptance. The increased incidence of coronary heart disease in persons subject to the types of socially structured strain we have depicted here provides support for the hypothesis that coronary heart disease may be viewed as an alternative to certain personality disorders, particularly for native-born American middle class Protestants, who are culturally not permitted to be weak or to fail to compete successfully. Stress may be normal and all life may be stressful, but no one can doubt that there are different kinds of stressors, that they impinge differentially on different persons, that there are different personality maneuvers and strategies for dealing with stress, and that the possible outcomes of individual encounters with intrapsychic conflicts or external stressors are various. The purpose of this report is to bring a small amount of empirical evidence to bear on the question of whether stress, as conceived by the social scientist, has any relationship to coronary artery disease. Although the connection is admittedly tenuous, the statistical evidence of association between social background variables and the disease is there, and it must be dealt with somehow. We believe that it supports the hypothesis that sociological and socio-psychological factors play a role in the complex etiology of coronary artery disease. However, we hasten to add that the present report provides only a limited and preliminary beginning to a very broad problem which should be subjected to a far more comprehensive, interdisciplinary attack than has hitherto been the case.
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32. 33. 34. 35.
WALTER I. WARDWELL, MERTON HYMAN and CLAUS B. BAHNSON
DURKHEIM. E.: Suicide (Trans. by SPAULDIN~ and SIMPSON). The Free Press, Glencoe, Ill., 19.51. ’ MERTON, R. K.: Social structure and Anomie, in Social Theory and Social Structure, Ch. 4. The Free Press, Glencoe, Ill., 1949. PARSONS,T. : The Sociul System, p. 252. The Free Press, Glencoe, Ill., 1951. CQTTRELL, L. S., Jr.: The. adjustment of the individual to his age and sex roles, Amer. social. Rev. 7, 617, 1942. GOODE, W. J. : A theory of role strain, Amer. social. Rev. 25,483, 1960. WEBER, M.: The Protestant Ethic and the Spirit of Capitalism (Trans. by PARSONS, T.). Allen & Unwin, London, 1930. PAINIER, R. C., RALSTON, L. S., FAWCE~, R. M., ZUKEL, W. J. and LEWIS, R. H.: Short-term study of coronary heart disease in a North Dakota community, J. Amer. med. Ass. 172, 1261, 1960. SYME, S. L., HYMAN, M. and ENTERLINE,P. E.: Some cultural factors associated with the occurrence of coronary heart disease. In preparation. WARDWELL,W. I., BAHNSON,C. B. and CARON, H. S. : Social and psychological factors in coronary heart disease, Hlth hum. Behav. 4, 155, 1963. EISENBERG,H., FELTNER, W. R., PAYNE,G. H. and HADDAD,C. A.: The epidemiology of coronary heart disease in Middlesex County, Connecticut. I. A preliminary report on methodology and incidence of primary myocardial infarction, 1. chron. Dis. 14, 221, 1961. WARDWEI-L.W. I., HYMAN. M, and BAHNSON,C. B.: Socio-environmental antecedents to coronary heart disease in 87 white males. In preparation. SROLE, L., LANGNER,T. S., MICHAEL, S. T., OPLER, M. K. and RENNIE, T. A. C.: Mental Health in the Metropolis: The Midtown Manhattan Study, Vol. I, The Thomas A. C. Rennie Series in Social Psychiatry. McGraw-Hill, New York, 1962. DAWBER, T. R., KANNEL, W. B., REVOTSKIE, N., STOKES,J., KAGAN, A. and GORDON,T.: Some factors associated with the development of coronary heart disease, Amer. 1. publ. Hlth 49, 1349, 1959. STAMLER,J., LINDBERG,H. A., BERKSON,D. M., SHAFFER,A., MICLER, W. and POINDEXIER, A.: Prevalence and incidence of coronary heart disease in strata of the labor force of a Chicago industrial corporation, J. chron. Dis. 11,405, 1960. EPSTEIN, F. H., BOAS, E. P. and SIMPSON, R.: The epidemiology of atherosclerosis among a random sample of clothing workers of different ethnic origins in New York City, J. clzron. Dis. 5, 300, 1957. WORLD HEALTH ORGANIZATION: Annual Epidemiological and Vital Statistics, 1957. E~ERLINE, P. E. and STEWART, W. H.: Geographic patterns in deaths from coronary heart disease, Publ. HIth Rep., Wash. 71, 846, 1956. ENTERLINE,P. E., RIKLI, A. E., SAUER, H. I. and HYMAN, M.: Death rates for coronary heart disease in metropolitan and other areas, Publ. Hlth Rep., Wash. 75, 759, 1960. BRESLOW, L. and BUELL, P.: Mortality from coronary heart disease and physical activity of work in California, J. chron. Dis. 11,421, 1960. KENT, A. P., MCC~OLL, J. R., SCHWEI~R. M. D. and WILLARD, H. N.: A comparison of coronary artery disease (ASHDg deaths in health areas of Manhattan, N.Y.C., Amer. .I. publ. Hlth 48, 200, 19.58. STAMLER, J.: Current epidemiologic, clinical, and laboratory research findings on the etiology of atherosclerosis, Neb. St. med. J. 41,75, 1956. LEE, R. E. and SCHNEIDER,R. F.: Hypertension and arteriosclerosis in executive and non-executive personnel, J. Amer. med. Ass. 167, 1447, 1958. LOGAN, W. P. D.: Social class variations in mortality, Publ. Hlth Rep., Wash. 69, 1217, 1954. BAHNSON,C. B. and WARDWELL,W. I.: Parent constellation and psychosexual identification in male patients with myocardial infarction, Psychol. Rep. 10, 831, 1962.
STRESS AND CORONARY THREE
FIELD
HEART
DISEASE
IN
STUDIES*
WALTER I. WARDWELL?,MERTONHYMANand CLAUS B. BAHNSON University
of Connecticut,
(Received THE
15
ASSESSMENT
January
Storrs, Conk 1963)
OF
STRESS
THE PURPOSEof this paper is to compare the findings from three separate field studies relating social background variables to the incidence of coronary heart disease. Although each of the studies is limited in scope, the similarity in their findings is sufficiently impressive to justify the formulation of tentative hypotheses implicating such variables as immigrant generation, urban or rural childhood background, socio-economic level, and degree of involvement in the predominant Protestant, Anglo-Saxon culture. Although there are presumably several intervening variables between such environmental characteristics and the pathogenic physiological processes involved in coronary heart disease, these more distant relationships may serve as indices or clues to significant factors in the etiology of this prevalent and puzzling disease. Specifically. it may make possible identification of sources of chronic stress potentially related to the onset of coronary heart attacks. The idea that stress of some kind is involved in the etiology of coronary heart attacks has long been popular among laymen, if not among many of the scientists studying heart disease. However, the concept stress is very difficult to deal with since it has so many different meanings. For some researchers it refers to aspects of the environment causing upheaval in the organism (e.g., noxious gases, infectious agents, work deadlines), while for others it refers to the reaction within the organism itself to such environmental conditions [l]. Then, too, workers in different disciplines formulate different conceptions of what is stressful. Heavy labor and long hours of work are phenomena of a quite different order from the heartbreaking loss of a loved one, the crushing disappointment of a life-long ambition, anxiety over financial problems, or the chronic irritation caused by an insufferable wife or employer. Each of these ‘stressors’ produces a different type of impact on the organism. Furthermore, the time span of stress can vary from a single episode to long-standing chronic stresses. On the one hand, a single traumatic event that causes a strong emotional reaction in the individual (e.g., anger or fear) may, through sympathetic-adrenal pathways, result in occlusive arterial spasm or thrombus formation; while on the other hand. ischemic heart disease may develop more gradually from a longstanding atherosclerotic process (possibly related to disturbed lipid metabolism) which has so severely narrowed the lumen of the coronary artery that a sudden *This research has been supported
by Grants H-4257 and H-6889 of the National Institutes of Health, and the Heart Disease Control Program of the U.S. Public Health Service. TAddress for reprints: Dr. Walter I. Wardwell, Associate Professor of Sociology, University of Connecticut, Storrs, Connecticut. 73
74
WALTERI. WARDWELL,MERTONHYMAN and CLAUS B. BAHNSON
demand on the heart muscle may quickly deplete the necessary blood supply and thus produce an infarct. Until the physiological mechanisms underlying the slow process of atherogenesis and the dramatic suddenness of thrombotic occlusion are well understood, it is unreasonable to expect the social scientist to explicate the intervening variables between such pathological processes and different kinds of stress. However, it seems reasonable to hypothesize that there may be a relationship between the different pathologies and different kinds of stress, for there is overwhelming evidence from the field of physiological psychology and psychosomatic medicine that cardiovascular functioning is related differentially to different emotional states of the psychobiological organism [2-81. There is also a well established body of literature attesting to wide variations in behavior, habits, and emotions between people from different societies or cultures (quite apart from inherited biological differences) in addition to individual differences within such groups. The sociologist and the social anthropologist delineate variations between broad groupings of people (e.g., by sex, age, nationality, class level, occupation) rather than between individuals as such, a procedure thoroughly familiar to the epidemiologist. As a technique for studying stress this approach offers some advantages over that of psychology, since the type of information required is easier to elicit than are personality data, and since less distortion is likely to occur with sociological variables (e.g., nationality, occupation) than with such psychological variables as sentiments and values when both are gathered retrospectively 191. Sociologists have long concerned themselves with the stressful impact on the individual of social conditions such as culture conflict and situational pressures. PARK’s ‘marginal man’ IlO] is probably the best known of the concepts referring to the effect of conflicts in the socio-cultural environment (see also ST~NEQUIST [ll]). DURKHEXM’Sterm Anomie [12] has come to be applied generically to all situations involving value conflict and confusion over role-definitions 1131. Where a person is second-generation (i.e., of immigrant parents) or where his parents are of differing ethnic or religious backgrounds, the individual experiences the anemic situation over many years, perhaps a whole lifetime. The impact on his personality is likely to be extensive, influencing such basic psychological characteristics as selfconcept, and mode of impulse regulation and ego defenses. PARSONS has applied the phrase ‘socially structured strain’ to situations-like that of the marginal man-which would be stressful for any person experiencing them [14]. COlTRELL formulates a number of propositions concerning roleadjustment (i.e., stress-reduction) as a function of the degree of clarity and specificity with which a role is defined, especially “the proportion of the social situations . . . for which there are explicit definitions of the reciprocal behavior expected”: lack of clarity in role definition results in “tension, anxiety, and frustration generated by the attempt to discover and play a given role” 1151. GOODE emphasizes that a wide range of role opportunities and choices adds to ‘role strain’ ‘[16-J. It is characteristic of tradition-oriented groups (e.g., those dominated by old-world cultures, rural mores, and authoritarian controls) that the number of role choices is smaller and roles tend to be less ambiguously defined than in nontradition-oriented groups. In general, a child socialized in such an environment
Stress and Coronary
Heart Disease in Three Field Studies
75
learns with less confusion the behaviour patterns expected of him and probably experiences little conflict concerning these fixed roles. By contrast, the ambiguous standards and requirements of a non-traditional environment may often burden the person for the rest of his life since many situations must be constantly re-valued and differentially responded to, quite apart from the additional stresses which may be imposed upon him by new environmental demands. DURKHEIMmade a second major contribution to the understanding of personality stress from a sociological point of view in his analysis of what he called egoismthe excessive individualism and mandatory personal autonomy historically associated with Protestantism. The Protestant, who, in Rousseau’s famous phrase, is ‘forced to be free’, bears a heavy load of responsibility for his actions and his fate. The resulting ‘cult of the individual’ has been a source of socially structured strain not only for Protestants, but for all those who have internalized the values of the ‘Protestant ethic’, which, in MAX WEBER’Sanalysis [17], is psychologically quite similar to DURKHEIM’Streatment of egoism and the cult of the individual. The fact that DURKHEIMcorrelated both egoism and Anomie with high suicide rates testifies to their close association with personality stress in his own thinking as well as in his data. The social scientist can determine to what extent such social characteristics believed to be stressful are associated with clinical coronary heart disease in a population. This certainly is a de-personalized way of dealing with the problem of stress which leaves out, or open to speculation, the role of possible intervening psychoIogica1 variables as well as the potentially independent, or interdependent, roles played by such physiological variables as diet, obesity, smoking, physical exercise, or inherited cardiovascular weakness. However, logically such physiological variables can be controlled for or studied in interaction with social and psychological variables, provided enough cases are assessed for each of the subgroups involved. An approximation to this is built into a retrospective study of myocardial infarction currently being carried on by W. I. WARDWELLand C. B. BAHNSONin southeastern Connecticut. In the present paper there is unfortunately insufficient space to present detailed tables showing the effect of diet, obesity, heredity, blood pressure, and smoking for each of the three studies independently and in interaction with the social background variables.* It should be emphasized, however, that when these physiological variables are introduced as controls, the effects of the social variables remain intact. THE
THREE
STUDIES
The first of the three studies we report on is, chronologically speaking, the North Dakota Heart Study, initiated in 1956 by the Heart Disease Control Program of the United States Public Health Service [IS, 191. In this study a special casereporting system was set up in cooperation with the physicians of six predominantly rural counties in North Dakota. These counties were selected in part because North Dakota has one of the lowest coronary heart disease mortality rates in the nation. A 30-min interview schedule was administered to each white male aged 35 and over (n =203) who had survived some manifestation of coronary heart *The
variables are discussed in the three separate studies [18-231.
76
WALTER I. WARDWELL, MERTQN HYMAN and CLAUS B. BAHNSON
disease, and also to a double sized (i.e., n= 406) comparison group of white males matched for age who were randomly selected by area1 sampling from the total population of the counties (excluding persons who had experienced some form of coronary heart disease). The second study is the Middlesex County Heart Study in Connecticut, which was begun in 1957 in conjunction with the Connecticut Department of Health [20-221. Two phases of this study are relevant here-one permitting comparison of heart patients with a group of persons suffering a different serious illness, the other permitting comparison with a ‘normal’ population. As in the North Dakota Study the subjects were all white males, but the heart patients in the Middlesex Study were limited to those aged 35-64 who had been medically diagnosed as having their first myocardial infarction. In the first phase of the Middlesex Study all white males aged 35-64 residing in the County who were diagnosed during a one-year period as having the first myocardial infarction (n= 32) were interviewed in their homes for an average of 3.6 hours, as were an equal number of age-matched white males from the same geographical area who were hospitalized during the same period for a lifethreatening or potentially disability-producing illness, but who were judged, on the basis of their medical history and electrocardiographic record, to be free of coronary artery disease. In the second phase of the study, all Middlesex County white males aged 35-64 diagnosed in a one and one-half year period as suffering their first myocardial infarction or as having died from a first coronary attack (n=87) were compared with an age-matched group of white males five times as large (n=435), randomly selected by area1 sampling from the total population of Middlesex County (excluding actual or probable cases of coronary heart disease). Data for this comparison were gathered using a slightly modified version of the interview schedule from the North Dakota Heart Study, information concerning deceased heart patients being obtained from the nearest surviving relative. Thus two sets of comparisons can be made from the Middlesex County data-one with a sick comparison group and one with a well comparison group. It should be noted that the coronary patients in the first phase of the Middlesex County Study comprise part of those studied in the second phase. The third study we are reporting on is much more limited than the other two, since the number of coronary cases is very small (n = 16) and since the data were originally gathered for a quite different purpose in the ‘Midtown Manhattan Study of Mental Disorders’ conducted from 1952 to 1961 by the Cornell Program in Social Psychiatry, Cornell University Medical College [23]. Through the courtesy of the directors of the study, and with the assistance of the physicians and hospitals of respondents who had indicated that they had ‘a heart condition’. we identified 16 cases of ‘arteriosclerotic coronary heart disease’ among the white males aged 40-60 included in the study. These cases were compared with two age-matched random samples of white males from the total interviewed in the Cornell Study (which selected respondents initially by 3-stage area1 probability sampling from a ‘gold coast to slum’ section of Manhattan). The first comparison group was eight times as large (M= 128) as the coronary group and consisted entirely of those free of any kind of heart condition, including hypertension (according to responses made during interviewing): the second group, eleven times as large (n= 176), was a random
Stress and Coronary
77
Heart Disease in Three Field Studies
sample of the total population interviewed (not excluding those who stated that they had a heart condition). The three studies thus represent a continuum from rural to highly urban environments. RESULTS
AND
DISCUSSION
The results from the three studies are presented in detail in Tables l-3 and are summarized in Table 4. In Tables l-3 the number of coronary and non-coronary cases, and the ratio of observed to expected cases of coronary artery disease, are shown for certain social background variables. In each case the ratio is determined by dividing the number of coronary cases in a particular category by the number of control cases in that category, adjusted for the difference between the total number of coronary and control cases in that study. In Table 4 only the ratios of observed to expected cases are shown. The social background variables selected clearly antedate the illness and thus could not have been affected by the experience of having had the illness: nor is recall of such variables likely to have been different for the coronary and non-coronary subjects studied. TABLET.
NORTHDAKOTAHEARTSTUDY
Ratios of observed to expected cases of coronary heart disease in white males aged 35 and over in six North Dakota counties, based on a comparison between 203 such cases and an age-matched probability sample of 406 ‘well’ (i.e., exclusive of actual or probable cases of CHD) persons resident in those counties.
Number of cases Immigrant generation 1st : Respondent and parents European-born 2nd : Both parents European-born 2nd: Father European, mother American 2nd: Father American, mother European 3rd or later: Both parents born in U.S. Occupational level of father Agricultural Non-agricultural Manual White collar Occupational level of respondent Agricultural Non-agricultural Manual White collar
CHD
‘Well
203
406
26 50 20 15 80
72 143 51 24 104
0.72 0.70 0.78 1.25 1.54
129
294
0.88
38 22
57 33
1.33 1.33
104
246
0.85
46 51
98 56
0.93 1.82
Ratio
We have chosen to report on relatively ‘objective’ items hypothesized to be related to emancipation from tradition-orientation, exposure to culture conflict, anomie and egoism. The indicators of tradition-orientation are: being first generation (i.e., born overseas), having a rural upbringing, being Catholic or having Catholic parents, being of Southern European, Eastern European, or FrenchCanadian stock, and being of a relatively lower occupational level. It is clear that the incidence rates are very low for persons in each of these categories. (One
WALTER I. WARDWELL, MERTOIVHYMAN and CLAUS B. BAHNSON
18
TABLE 2. MIDDLESEX COLJNTY HEARTSTLJDY
Ratios of observed cases ofmyocardialinfarction to expected cases, based on two types of comparison: (1) 32 surviving primary myocardial infarctions occurring in residents of Middlesex County during a one-year period compared with a series of 32 age-matched hospitalized persons free of coronary heart disease; and (2) 87 surviving and non-surviving primary myocardial infarctions occurring in residents of Middlesex County during a period of a year and a half compared with an age-matched probability sample of 435 ‘well’ (i.e., exclusive of actual or probable cases of myocardial infarction) persons residNon-whites, females, and persons under 35 years or over 64 years are ent in Middlesex County. excluded from both comparisons. M.T.
Other sick Ratio
435 ___-
J
0.50 0.92 1.67* 1.29
12 23 10 39
78 142 38 168
0.77 0.81 1.32 1.16
9 18 1 3
19 6 3 3
0.47 3.00 0.33* 1.00*
20 45 5 10
198
0.51
Religion of respondent Catholic Protestant Jewish
11 20 1
19 10 3
0.58 2.00 0.33*
Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European
7 23
15 14
Childhood Rural Urban
6 26
Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant,
1 Catholic)
32
5 12 5 9
10 13 3
‘Well’ Ratio
87
Number of cases __Immigrant generation 1st : Respondent and parents European-born 2nd: Both parents European-born 2nd: One parent European-born 3rd or later: Both parents born in U.S.
32
M.I.
177
1.27
19 21
1.32 2.38
28 52 4
213 194 18
0.66 1.34 1.11
0.47 1.64
20 64
157 258
0.64 1.24
9 23
0.67 1.13
19 67
138 296
0.69 1.13
11 21
15 16
0.73 1.31
48 32
314 114
0.76 1.40
12 20
20 12
0.60 1.67
56 31
298 96
0.94 1.66
environment
Occupational Lower Higher
level of father
Occupational Lower Higher
level of respondent
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
possible exception, the farm-born migrants to New York City, is discussed below.) Much higher rates are found for persons emancipated from tradition-orientation and for those experiencing cultural heterogeneity and varying degrees of anomie: secondor later-generation Americans (in particular those with one parent American-born and the other foreign-born), persons with an urban upbringing, those whose parents are of different religions, people of Old Yankee or Northwestern European stock, and those who were of or have achieved a relatively high occupational level. In the Midtown Manhattan Study and in the ‘other sick
Stress and Coronary TABLE
3.
79
Heart Disease in Three Field Studies MIDTOWN
MANHATTAN STUDY
Ratios of observed to expected cases of ‘arteriosclerotic coronary heart disease’ in white males aged 4&60 in the Cornell University Medical College’s, Midtown Manhatten study, based on comparisons between 16 such cases and an age-matched random sample of 128 ‘well’ (i.e., free of any kind of heart condition, including hypertension) persons; and with an age-matched random sample of 176 persons (including those with heart conditions) selected from the total interviewed. CHD
‘Well’
16
128
6 5 2 3
67 27 7 27
0.72 1.48 2.29* 0.88*
96 41 8 30
0.69 1.34 2.15* 1.10*
4 10 0 1
40 47 23 11
0.80* 1.70 o.oo* 0.73*
60 71 19 21
0.73* 1.55 o.oo* 0.52*
4 9 0
47 46 18
0.68* 1.57 o.oo*
61 70 15
0.72* 1.41 o.oo*
3 12
42 69
0.57* 1.40
58 98
0.57* 1.35
Childhood environment Farm Village, town, city City over 500,000 (other than N.Y.C.) New York City
4 4 0 8
14 59 24 30
2.28* 0.54* o.oo* 2.13
17 72 39 47
2.59* 0.61* o.oo* 1.87 _
Occupational Lower Higher
level of father 9 7
69 59
1.04 0.95
101 14
0.98
Occupational Lower Higher
level of respondent 5 11
65 61
0.62 1.44
94 80
0.58 1.51
Number of cases Immigrant generation 1st: Respondent and parents European-born 2nd: Both parents European-born 2nd: One parent European-born 3rd or later: Both parents born in U.S. Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant,
1 Catholic)
Religion of respondent Catholic Protestant Jewish Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European
Ratio
Normal
Ratio
176
1.05
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
comparison group of the Middlesex County Study the number of subjects of religiously intermixed parentage is probably too small to be reliable, but the ‘well’ comparison in the latter study provides a reliable result in the predicted direction. In general there is a reassuring consistency among the findings from the three studies (including two different comparison groups in the Middlesex County Study). The differences among the three sets of results appear to us to be relatively minor and to be comprehensible in view of the different locales in which they were conducted. The fact that the published epidemiological literature on coronary heart
80
WALTER I. WARDWELL, MERTON HYMAN
TABLET.
SUMMARY
and CLATJS B. BAHNSON
OF THE THREE STUDIES
Summary of ratios of observed to expected cases of myocardial infarction or arteriosclerotic heart disease in the Middlesex County, Midtown Manhattan, and North Dakota studies. North Dakota
Type of comparison group Number of experimental cases Number of comparison cases Immigrant generation 1st : Respondent and parents European-born 2nd: Both parents European-born 2nd : One parent European-born 3rd or later: Both parents born in U.S. Religion of parents Both Catholic Both Protestant Both Jewish Mixed (1 Protestant, 1 Catholic) Religion of respondent Catholic Protestant Jewish Ethnic group (nationality or stock) Southern European, Eastern European, and French-Canadian Old Yankee and Northwestern European Childhood environment Rural Urban Farm Village, town, city City over 500,000 (other than N.Y.C.) New York City Occupational level of father Lower Higher Occupational Lower Higher
Middlesex County
coronary
Midtown Manhattan
‘Well’
Other sick
‘Well’
‘Well’
Normal
203 406
32 32
87 43.5
16 128
16 176
0.72 0.70 0.93 1.54
0.50 0.92 1.67* 1.29
0.77 0.81 1.32 1.16
0.72 1.48 2.29* O.&S*
0.69 1.34 2.75* 1.10*
-
0.47 3.00 0.33*
1.oo*
0.51 1.27 1.32 2.38
0.80* 1.70 o.oo* 0.73*
0.73* 1.55 o.oo* 0.52*
-
0.58 2.00 0.33*
0.66 1.34 1.11
0.68* 1.57 o.oo*
0.72* 1.41 o.oo*
-
0.47 1.64
0.64 1.24
0.57* 1.40
0.57* 1.35 -
0.88 1.33 -
0.67 1.13 -
0.69 1.13 -
2.28* 0.54* o.oo* 2.13
2.59* 0.61* o.oo* 1.87
0.95 1.33
0.73 1.31
0.76 1.40
1.04 0.95
0.98 1.05
0.87 1.82
0.60 1.67
0.94 1.66
0.62 1.44
0.58 1.51
level of respondent
*Because of the small number of cases on which certain of the ratios are based, they may be excessively influenced by chance factors.
disease presents a somewhat inconsistent picture in regard to some of the variables reported here provides a setting for discussing the results of the three studies. For example, DAWBER and his co-workers in a preliminary report from the projected 20-year Framingham Heart Study cite a coronary heart disease rate for their foreign-born subjects higher than that for their native-born subjects [24],
Stress and Coronary Heart Disease in Three Field Studies
81
while STAMLERfound in a study of the male labor force of a Chicago utility corporation that the incidence rate of new coronary heart disease for native-born skilled workers and foremen was three times the rate for foreign-born workers in these categories [25]. In the three studies we are reporting, the lowest rates of coronary heart disease are found among the foreign-born, with much higher rates found among native-born subjects, whether in the second or later generations. The next to lowest rates are found, in the Middlesex and North Dakota studies, among those of the second generation with both parents born in Europe, whereas those of the second generation with one parent born in Europe and the other in the United States reveal the highest coronary heart disease rates of all (except for the third generation in the North Dakota Study). The explanation may be that culture conflict is greater where represented within the parental family than when experienced only outside the family. Similarly, the higher rate among North Dakota respondents if the father, rather than the mother, is the American-born parent may be associated with unusual stress in the child’s reorientation from an early motherrelationship to a later father-relationship, which in the case of a European-born mother and an American-born father would be most sudden and abrupt. Although religious differences in the incidence of coronary heart disease go unmentioned in the literature, religion is clearly a significant variable in the present report. In the studies where data are available the ratio of observed to expected cases among Protestants, whether based on the respondent’s reported religion or that of his parents, is 2-7 times that among Catholics. Moreover, the incidence for Protestants is equally high in all generations; though Catholics attain their highest rate in the second generation, even there it is only half the Protestant rate. The figure for Jews may be unreliable because of small numbers, but it is worth noting that the statistically most acceptable ratio (that for the ‘well’ comparison group in Middlesex County, based on 87 coronary and 435 ‘well’ cases) reveals a Jewish rate approximately the same as that for Protestants. Few epidemiological studies report on ethnic differences associated with coronary heart disease within the same community. Although DAWBERdiscovered no differences in the Framingham Study [24], EPSTEIN found that Jewish clothing workers in New York City had a rate twice as high as that of Italian clothing workers [26]. Variations among ethnic groups in the present studies, it should be noted, conform to the general pattern for coronary heart disease mortality rates in Europe, where higher rates are found in the Northwestern European countries and lower rates in the Eastern and Southern European countries 1271. For the United States there is a well-established geographic pattern of mortality from coronary heart disease-namely, that age-adjusted death rates are far higher in the urban and industrial areas than in rural areas ‘[28, 291. BRESLOWand BUELL report that farmers and farm laborers have a much lower mortality rate from arteriosclerotic and coronary heart disease than do non-farmers, even when the latter are engaged in heavy physical activity ‘[30]. If such differences are related to life style it would seem likely that within most population groups there would be a difference between those reared in urban versus those reared in rural areas. In the Middlesex County Study this comparison is based on responses to the question: “Did you ever live on a farm for as much as 5 years at a time before you were 18 years old?“, while in the North Dakota Study the data indicate whether the
82
WALTER I. WARDWJXL, MERTON HYMAN and CLAUSB. BAHNSON
respondent’s father was in agricultural or non-agricultural employment. In both of these studies the ratio of observed to expected cases of heart disease is nearly twice as great among the city-reared; but in the Midtown Manhattan Study in New York City, on the other hand, those reared on a farm appear to have the highest rate of all, if we can place confidence in the small number of cases. In the latter instance the explanation may involve a completely different interacting variable not measurable in the other two studies-that of the stressful effects of migration from a farm to a metropolis, and the resulting cultural discontinuity involved. Occupational level is used as an index of socio-economic status. Like the items already discussed, father’s occupational level is clearly antecedent to the development of coronary heart disease in the son and therefore could logically stand in some kind of causal relationship to it or be an index of some other variable that does so. The patient’s own occupational level, on the other hand-though existing prior to the clinical manifestation of coronary artery disease-does not necessarily precede all the other variables potentially involved in its etiology, for both the disease and occupational choice could logically result from some third variablefor example, personality type. The published literature contains frequent reference to the social class level of persons with coronary heart disease, without consistent tidings. DAWBER[24], KENT et al. [31], and STAMLER[32] find that coronary heart disease rates are lower for persons at the higher socio-economic levels, while LEE and SCHNEIDER[33], LOGAN1341, and STAMLERhimself in another study [25] report opposite findings consonant with the three studies reported here, in which the coronary subjects are more likely to have come from and to have achieved a relatively higher occupational level.
SUMMARY
AND
CONCLUSION
Differences found in the three studies according to occupational level, rural-urban background, ethnic background, religion, and generation all overlap each other, but it is not feasible to present tables showing the effect of each. In Connecticut the variables carrying the greatest weight when other variables are controlled are religious affiliation and occupation. On the other hand, in North Dakota, where religion was not studied and, due to the relatively small number of Catholics in the state, would probably not constitute as significant a source of variation as it does in Connecticut, the key variables when other variables are controlled are immigrant generation and urban-rural background. In Connecticut, where coronary mortality rates are high in general, the exceptionally low cell in a two-by-two table relating religion and occupation is that for Catholics whose fathers were in low status occupations. In North Dakota, where rates are low in general, the exceptionally high cell in the two-by-two table relating urban-rural background and immigrant generation is that for the sons of American. born fathers in urban occupations. In the predominantly farming area of North Dakota the more important socio-economic distinction is between those whose fathers were farmers and those whose fathers were not; while in Connecticut, where few of the respondents were raised on a farm and where the economy is industrialized, the important socio-economic distinction concerns occupational level. In both cases the more vulnerable subjects are those who are closest to the American
Stress and Coronary
Heart Disease in Three Field Studies
83
urban middle class Protestant ethos. The findings from the Midtown Manhattan Study are compatible. Examination of the personality characteristics of coronary heart disease patients is beyond the scope of this paper; furthermore, such an exploration is not feasible for certain of these studies, due to limitations in the types of data gathered. However, intensive study of personality factors in the coronary and sick control comparison groups of the Middlesex County Study and in the Midtown Manhattan Study reveals tendencies among coronary cases toward particular personality stresses consonant with the sociological findings we report here (cf. [35]). The idea that stress may be resolved via a psychosomatic discharge route as an alternative to psychological disorganization is gaining scientific acceptance. The increased incidence of coronary heart disease in persons subject to the types of socially structured strain we have depicted here provides support for the hypothesis that coronary heart disease may be viewed as an alternative to certain personality disorders, particularly for native-born American middle class Protestants, who are culturally not permitted to be weak or to fail to compete successfully. Stress may be normal and all life may be stressful, but no one can doubt that there are different kinds of stressors, that they impinge differentially on different persons, that there are different personality maneuvers and strategies for dealing with stress, and that the possible outcomes of individual encounters with intrapsychic conflicts or external stressors are various. The purpose of this report is to bring a small amount of empirical evidence to bear on the question of whether stress, as conceived by the social scientist, has any relationship to coronary artery disease. Although the connection is admittedly tenuous, the statistical evidence of association between social background variables and the disease is there, and it must be dealt with somehow. We believe that it supports the hypothesis that sociological and socio-psychological factors play a role in the complex etiology of coronary artery disease. However, we hasten to add that the present report provides only a limited and preliminary beginning to a very broad problem which should be subjected to a far more comprehensive, interdisciplinary attack than has hitherto been the case.
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