Vital exhaustion as risk indicator for myocardial infarction in women

Journal of Psychosomatic Research, Vol. 37, No. 8, pp. 881 890, 1993. Printed in Great Britain.

0022-3999/93 $6.00+.00 (c) 1993 Pergamon Press Ltd

VITAL EXHAUSTION AS RISK INDICATOR FOR MYOCARDIAL INFARCTION IN WOMEN A. APPELS, P. R. J. FALGER and E. G. W . SCHOUTEN

(Received 16 February 1993; accepted in revised form 21 May 1993) Abstract--To test the hypothesis that 'vital exhaustion' (VE), a state characterized by unusual fatigue, increased irritability, and feelings of demoralization, precedes the onset of myocardial infarction (MI) in females, 79 females hospitalized with a first MI (mean age: 59.3; SD = 9.3) and 90 females hospitalized in the departments of general and orthopaedic surgery (mean age: 57.4; SD = 9.1), were compared on the retrospective form of the Maastricht Questionnaire (MQ). Defining "exhaustion' as a score above the median of the MQ, 63% of the cases and 39% of the controls were exhausted before hospitalization (X2 = 10.02; p < 0.00). The relative risk associated with exhaustion, after controlling for age, smoking, coffee consumption, diabetes, hypertension, nonanginal pain, and menopausal status, was estimated as 2.75 (95% CI:I.28-5.81; p < 0.01), thus corroborating the hypothesis. Exploratory analyses of the origins of exhaustion in these females showed that of all biographical characteristics, holding a job and simultaneously taking care of the household was most strongly associated with elevated exhaustion scores. INTRODUCTION FEELINGS o f u n u s u a l t i r e d n e s s and l a c k o f e n e r g y h a v e b e e n f o u n d to be the m o s t p r e v a l e n t p r e c u r s o r s o f m y o c a r d i a l i n f a r c t i o n ( M I ) a n d s u d d e n d e a t h [ 1 ]. T h e s e f e e l i n g s r e f l e c t a state o f m e n t a l and p h y s i c a l e x h a u s t i o n . A d u l t s u b j e c t s w h o find t h e m s e l v e s in such a state, m o s t o f t e n c o m p l a i n a b o u t a loss o f e n e r g y , t i r e d n e s s , loss o f l i b i d o , i n c r e a s e d i r r i t a b i l i t y , and f e e l i n g d e f e a t e d . M o s t patients attribute t h e s e f e e l i n g s to a l o n g - s t a n d i n g p r o b l e m that t h e y h a v e b e e n u n a b l e to s o l v e , o r to a real o r s y m b o l i c loss. W e h a v e l a b e l e d this state as ' v i t a l e x h a u s t i o n ' ( V E ) , c h a r a c t e r i z e d by (1) u n u s u a l f a t i g u e and loss o f e n e r g y ; (2) i n c r e a s e d i r r i t a b i l i t y ; and (3) f e e l i n g s o f d e m o r a l i z a t i o n . T h i s state c a n be m e a s u r e d by the M a a s t r i c h t Q u e s t i o n n a i r e ( M Q ) . It has b e e n s h o w n that M I o c c u r s m o r e than t w i c e as o f t e n a m o n g t h o s e w h o a r e e x h a u s t e d , c o m p a r e d to t h o s e subjects w h o a r e not e x h a u s t e d [ 2 ] . H o w e v e r , all i n f o r m a t i o n w i t h r e g a r d to V E as a risk i n d i c a t o r for M I has b e e n c o l l e c t e d in males. T h e r e f o r e , the m a j o r a i m o f the p r e s e n t study was to test the h y p o t h e s i s that V E is also a s s o c i a t e d w i t h in an i n c r e a s e d risk f o r first M I in f e m a l e s . T h e s e c o n d a i m o f the study w a s to o b t a i n m o r e insight into the s o m a t i c and b i o g r a p h i c a l o r i g i n s o f V E in f e m a l e s . METHOD

Subjects The cases comprised consecutive series of female patients with first documented MI who had been hospitalized in the departments of cardiology of the Academic Hospital in Maastricht and the De Wever Hospital in Heerlen between September 1988 and June 1990. These constitute the two largest hospitals Dept Medical Psychology, University of Limburg, Box 616, 6200 MD, Maastricht, The Netherlands. This study was supported by a grant from the Dutch Heart Foundation. 881

882

A. APPELS et al. TABLE

I.--PRIMARY

REASONS FOR HOSPITALIZATION

PARTICIPATING

IN

CONTROLS

N

%

l Traumatic fractures (e.g. ankle, upper leg)

44

49

2 Acute abdomen (e.g. cholecystitis, appendicitis)

30

33

3 Abscess/infection (e.g. perianal abscess)

8

9

4 Other reasons (e.g. thrombosis of leg)

8

9

in the South Limburg region of The Netherlands. The diagnosis of definite first MI was based on: (a) the clinical history taken by a cardiologist; (b) standard ECG readings; and (c) maximum plasma enzyme levels. The controls were females who had been hospitalized in the departments of general surgery and orthopaedic surgery of the same hospitals in the same period (Table I). Controls who had suffered from MI in the past were excluded. In both hospitals, all new cases with the diagnosis of first MI were visited once a week. Each patient was told the purpose and procedures of the study. Once she agreed to participate, she received a set of questionnaires and a tentative appointment was made for an interview at home after discharge from the hospital. The interviews took place within 1-5 months after discharge (mean duration: 2.0 months; sD = 0.84L For every case who agreed to participate, a control subject was approached following the same procedure. Instruments Vital exhaustion was assessed by means of the Maastricht Questionnaire (MQ). This is a 21 -item selfadministered checklist with a minimumscore of 0 and maximum score of 42 [3 ]. All subjects were asked to indicate how they felt in the last few months preceding hospitalization. Medical data was collected from hospital records and during the interview at home and included: age, Quetelet index, angina pectoris, hypertension, diabetes, use of oral contraceptives, menopausal status, bilateral oophorectomy, smoking, and family history of coronary artery disease (CAD). Angina pectoris was assessed by means of the Rose Questionaire [4]. Hypertension and diabetes were defined as ever having been treated for these cardiovascular risk factors; hypertension during pregnancy, however, was ignored. Menopausal status was coded as a variable with three categories (i.e., pre-menopausal, less than 12 yr post-menopausal, and more than 12 yr post-menopausal, 12 years being the median duration of post-menopausal years in this study). Smoking was defined as the number of cigarettes smoked per day during the 6 months prior to hospitalization. Subjects were dividided into: (1) non-smokers: (2) moderate smokers (i.e., 1-19 cigarettes); and (3) heavy smokers (i.e., 20 cigarettes or more). Due to the small number of subjects reporting the occurrence of MI in a sibling, a family history of CAD was considered positive if one parent or sibling had every suffered a fatal or non-fatal MI. Because some control patients might have suffered from pain or bodily discomfort in the months or weeks before hospitalization leading to elevated MQ scores, a variable "non-anginal pain" was constructed to control for this confounding factor. All subjects were asked how often they had suffered from pain or bodily discomfort in the half year before hospitalization. Those who reported that they often or always suffered from pain but who were free of angina pectoris were classified as suffering from non-anginal pain. All others were classified as free from non-anginal pain. Biographical data included educational and marital status and a number of stressors that may have occurred over the life-span. These are listed in Appendix 1. Statistical analyses Statistical analyses began, first, with inspecting the frequency distributions of the MQ in cases and controls and by computing the internal consistency of the MQ in both groups, because there was no information available about these psychometric properties of the scale in females. Second, univariate analyses were done to compare cases and controls with respect to somatic risk factors and VE and to compute mean exhaustion scores across several levels of somatic risk factors. Third, a number of multiple logistic regression analyses were performed to estimate the relative risk associated with

Exhaustion and infarction in women

883

exhaustion. In these analyses the MQ was dichotomized at the median of the distribution (19 or higher). In the first model, the risk associated with exhaustion was computed while adjusted for age (as a continuous variable) and non-anginal pain. In the second model, this risk was computed while adjusted for age, non-anginal pain, menopausal status, and somatic risk factors as listed in Table II. Females with bilateral oophorectomy (N = 17) were omitted from the analyses including menopausal status. In the third model, angina pectoris was added to the variables included in model 2 in order to control for feelings of exhaustion that may have been caused by manifest heart disease. Angina pectoris was not included in the second model because it may be considered as an endpoint instead of as a risk factor. Direct and stepwise methods were used to obtain the most parsimoneous model. In the stepwise analyses, the likelihood ratio test was used to select independent variables to be removed. The data were analysed using SPSS/PC 4.0 [ 5 ] .

TABLE II.--DEMOGRAPHIC,

H E A L T H , AND PERSONALITY

CHARACTERISTICS OF FEMALE CASES W I T H N O N - F A T A L FIRST

MI

AND H O S P I T A L C O N T R O L S

Cases (79)

Controls (90)

Age distribution: 35-49 5O-59 60-69

!1 22 46

14 30 46

X2 = 0.87 p = 0.64

Level of education: primary only some secondary higher education

48 25 6

41 30 19

X 2 = 7.08 p = 0.03

Marital status: married single

72 28

68 22

X2 = 0.25 p = 0.61

Number of children: none 1-2 3-4 5 or more

6 36 22 15

12 27 37 14

X2 = 6.45 p = 0.09

Current smoking: non smokers moderate smokers heavy smokers

31 15 33

55 23 12

X2 = 17.50 p = 0.00

Diabetes: present absent

12 67

4 86

X2 = 5.67 p = 0.01

Hypertension: present absent

42 37

23 67

x 2 = 13.55 p = 0.00

Family history of CAD: positive negative

44 35

37 53

X2 = 3.59 p = 0.06

Angina pectoris: present absent

16 63

5 85

x 2 = 8.35 p = 0,00

Non-anginal pain: present absent

17 62

25 65

X2 = 0.88 p = 0.34 (Continued).

A. APPEkS et al.

884

TABLE lI.--continued

Cases (79)

Controls (90)

Coffee consumption (cups p/day): 47 0-5 6 or more 32

68 22

x 2 = 4.99 p = 0.03

Menopausal status: pre post ( 1 - 1 2 years) post ( 1 3 + years)

11 29 39

14 41 35

x 2 = 1.93 p = 0.38

Oral contraceptives: ever used never used

28 51

33 57

X 2 = 0.03 p = 0.87

Bilateral oophorectomy: present absent

7 72

10 80

x 2 = 0.23 p = 0.63

Vital exhaustion: not exhausted exhausted

29 50

55 35

X2 = 10.02 p = 0.00

Mean MQ score SD

20.6 (11.9)

17.0 (11.2)

t = 2.02 p=0.04

In order to obtain more insight into the origins of VE in females, univariate analyses were performed that related MQ scores with the biographical characteristics as listed in Appendix 1. W o m e n who never bad a paying job were excluded from the analyses relating VE to work variables (N = 16). The risk that change fluctuations would influence the results of this exploratory analysis was reduced by combining cases and controls. Multiple regression analyses were performed to identify the variables most strongly associated with exhaustion. RESULTS

In all, 95 MI-patients were invited, of whom 79 (83%) agreed to participate. Moreover, 118 controls were approached, 90 (76%) of whom participated in the study. The main reasons given for non-participation were: 'not interested' (23%), 'subject considered private' (23 %), and 'no permission from husband' (16 %). Inspection of the respective distributions of the MQ showed a platykurtic form in both groups; the kurtosis was - 0 . 8 2 and - 1.11, respectively. Cronbach's alpha was 0.90 with the cases and 0.92 with controls. Although the shape of the frequency distributions was rather dissimilar from the skewed distribution usually observed with males, the psychometric properties of the MQ allowed us to test our hypothesis. Table II presents the main characteristics of cases and controls. There were no significant differences with respect to age, marital status, number of children, menopausal status, use of oral contraceptives, bilateral oophorectomy, and the prevalence of non-anginal pain. A family history of CAD was reported marginally more often by cases than by controls (p = 0.06). The educational status of the cases was somewhat lower than that of the controls (p = 0.03). Smoking, elevated coffee consumption, angina pectoris, and a history of hypertension or diabetes were more prevalent among cases than controls. The mean exhaustion scores of cases and controls differed significantly in the predicted direction. Defining exhaustion as a score above the median of the MQ, 63% of the cases and 39% of the controls were exhausted before hospitalization 0( 2 = 10.02; p < 0.00).

Exhaustion and infarction in women

885

Table III presents the associations between demographic characteristics and somatic risk factors on the one hand and VE on the other hand. This table shows that VE was not significantly associated with age, number of children, coffee consumption, history of hypertension, use of oral contraceptives, bilateral oophorectomy, and angina pectoris. Elevated scores were, however, observed among heavy smokers, post-menopausal and single females, and among subjects who were suffering from diabetes or non-anginal pain. Level of education was negatively associated with exhaustion scores. This is mainly due to the low mean score of the subjects who attained the highest education. TABLE III.--AssOCIATIONS BETWEEN VITAL EXHAUSTION AND DEMOGRAPHIC OR HEALTH CHARACTERISTICSOF FEMALE CASES WITH NON-FATAL FIRST MI AND HOSPITAL CONTROLS N

Mean

(so)

F/t-test

p

Age: 35-49 50-59 60-69

25 52 92

17.6 18.6 19.1

(13.9) (11.3) (11.4)

0.16

0.85

Level of education: primary only some secondary higher education

89 55 25

20.1 19.9 11.2

(11.4) (11.2) (11.4)

6.45

0.00

125 44

17.5 22.3

(11.4) (11.9)

2.40

0.02

Number of children: none 1-2 3-4 5 or more

18 63 59 29

22.1 18.8 18.9 16.1

(11.8) (12.9) (10.5) (11.3)

1.02

0.38

Current smoking: non smokers moderate smokers heavy smokers

86 38 45

17.2 16.2 23.8

(11.9) (11.0) (10.5)

6.12

0.00

Diabetes: present absent

16 1"3

23.5 18.2

(6.7) (12.0)

2.74

0.00

Hypertension: present absent

65 104

19.6 18,2

(11.1) (12.1)

0.73

0.47

8l 88

19.2 18.3

(10.6) (12.6)

0.54

0.59

Angina pectoris: present absent

21 148

22.4 18.2

(11.9) (9.6)

1.56

0.12

Non-anginal pain: present absent

42 127

26.3 16.2

(10.8) (10.9)

5.20

0.00

Marital status: married single

Family history of CAD: positive negative

(Continued).

886

A. APPELSet al. TABLE III.--continued N Coffee consumption (cups p/day): 0-5 115 6 or more 54

Mean

(SD)

F/t-test

p

17.7 20.8

(12.1) (10.7)

1.60

o. II

Menopausal status: pre post (1-11 years) post (124- years)

25 70 68

15.0 17.3 21.3

(13.9) (11.2) (10.9)

3.67

0.03

Oral contraceptives: ever used never used

61 108

18.0 19.0

(11.9) ( 11.6)

0.52

0.20

Bilateral oophorectomy: present absent

17 152

19.8 18.6

(12.2) (11.7)

0.39

0.63

The direct and stepwise algorithms that were used to compute the estimated relative risks, resulted in almost similar models. Quetelet index, coffee c o n s u m p t i o n , positive family history of C A D , and m e n o p a u s a l status did not discriminate between cases and controls in the direct model and were r e m o v e d in all stepwise models. The relative risk associated with exhaustion and adjusted for age and n o n - a n g i n a l pain was 3.49 (95% C I : I . 7 5 - 6 . 9 6 ; p < 0.00). This odds ratio dropped to 2.75 (95% C I : I . 2 8 - 5 . 8 1 ; p < 0.01) when adjusted for s m o k i n g , h y p e r t e n s i o n , diabetes, age and n o n - a n g i n a l pain (Table IV). This decrease was m a i n l y due to the association between V E and smoking. The inclusion of a n g i n a pectoris in the model resulted in a slight decrease of the odds ratio (OR = 2.40; 95% C I : I . 1 1 - 5 . 2 6 ; p = 0.02). O f the biographical data related to childhood and adolescence, long-lasting conflicts, u n e m p l o y m e n t , and financial p r o b l e m s in the family were all positively and significantly associated with VE. In contrast none of the work-related variables were associated with VE. H o w e v e r , as shown in T a b l e V, those females who at the time they held a j o b were simultaneously taking care of the household had significantly

TABLE

IV.--EsTIMaTED

NON-FA'IAL FOR C U R R E N T

MI

RELATIVE

RISKS [ O D D S R A T I O S ( O R ) ]

ASSOCIATED WITH

VIIAL

EXHAUSTION,

FOR F1RSF

CONIROI.LING

SMOKING, DIABETES, HYPERTENSION, NON-ANGINAL COFFEE CONSUMPTION, AND AGE

PAIN,

B

SE

OR

p

Current smoking: 1--19 cigarettes 20+ cigarettes

0.33 2.08

0.46 0.50

1.40 8.04

0.00

Diabetes

1.31

0.67

3.71

0.05

Hypertension

1.36

0.39

3.90

0.(g)

-1.17

0.46

0.31

0.01

Age

0.04

0.02

1.04

0.07

Vital exhaustion

1.01

0.39

2.75

0.01

Non-anginal pain

Exhaustion and infarction in women TABLE V.--MEAN

EXHAUSTION

(MQ) SCORES

887

OF F E M A L E S W H O E V E R

H E L D A JOB W I T H OR W I T H O U T S I M U L T A N E O U S L Y T A K I N G C A R E OF THE HOUSEHOLD

N

No household Household

Mean

(so)

32

11.4

(8.9)

120

20.8

(11.7)

t

p

4.25

0.00

elevated MQ scores compared to those who held a job but were not taking care of the household. Of the other biographical data related to adulthood, unwanted childlessness, educational problems with children, financial problems and prolonged marital problems were all positively associated with exhaustion. Due to missing data, 55 subjects could not be included in the multivariate explorations of those variables most strongly associated with VE. Analyses that replaced missing data by mean substitution resulted in rather different models, compared to the analyses based upon subjects without missing information. Moreover, stepwise and direct methods resulted in different models. Because no parsimoneous and stable model could be established, these multivariate explorations were discontinued. However, it is of importance to note that in all analyses the variable 'holding a job and simultaneously taking care of the household' showed the strongest association with exhaustion scores. DISCUSSION The main finding of this study was that VE precedes the onset of non-fatal first MI in adult females. The significantly higher prevalence of this state among coronary cases than in controls prior to hospitalization could only be partially attributed to angina pectoris or to the associations of VE with some classic risk factors for coronary artery disease. To what extent is the strength of the association between VE and MI in this study over- or underestimated? How much would the reports of patients about their mental and physical state before the occurrence of the disease have been influenced by the disease itself?. In order to diminish the chance that hospitalization by itself would seriously affect the data, hospital controls were employed instead of healthy controls. This may have resulted in an underestimation of the odds ratio because pain or anticipatory anxiety related to the primary reason for hospitalization among controls may have induced a rise in MQ scores, for example by inducing sleep problems. In this study, we could only control for non-anginal pain. Subjects who are unexpectedly afflicted by a serious new disease generally try to find an explanation for their condition. This search for meaning may affect the recollection of past emotions and events, leading to an overestimation of the risk associated with VE. Experimental research has shown that this confirmatory search for meaning is not, however, directed at premonitory symptoms but rather at risk behaviours that are thought to be causal [6]. Therefore, it may be thought that it is not the tiredness preceding the coronary event that is under scrutiny after MI, but rather the event(s) or conditions(s) that may have caused the loss of energy. The precision of the estimate of the odds ratio may also have been influenced by imperfections in the assessment of the risk factors that were controlled for. We had

888

A. APPELSet al.

to rely upon self reports about h y p e r t e n s i o n , which might have been influenced by a higher detection rate a m o n g those females w h o visited their d o c t o r s b e c a u s e o f tiredness, leading to an u n d e r s t i m a t i o n o f the o d d s ratio. S m o k i n g was assessed as current s m o k i n g . T h o s e who s t o p p e d s m o k i n g w e r e c o d e d as n o n - s m o k e r s . Because V E and s m o k i n g were p o s i t i v e l y c o r r e l a t e d , this m a y have resulted in a slight o v e r e s t i m a t i o n o f the odds ratio. W e e x p e c t e d a positive association b e t w e e n m e n o p a u s a l status and M I , since an increase in the incidence o f a t h e r o s c l e r o s i s and c a r d i o v a s c u l a r d i s e a s e after m e n o pause has g e n e r a l l y been o b s e r v e d , although not all studies a g r e e on these findings [ 7 - 9 ] . The p e r c e n t a g e o f p r e m e n o p a u s a l females in this study was rather small (i.e., 13.6%) and m a n y others had difficulty estimating the p r e c i s e y e a r in which their m e n s t r u a t i o n stopped, as was reflected in the t e n d e n c y to a n s w e r ' a b o u t ten or eleven y e a r s a g o ' to this question. F u r t h e r m o r e , we w e r e not able to c h e c k hospital r e c o r d s with respect to the causes o f g y n a e c o l o g i c a l s u r g e r y . M o s t r e c o r d s w e r e rather i n c o m p l e t e on h o r m o n e - r e p l a c e m e n t therapy d u r i n g m e n o p a u s e . T h e s e limitations m a y e x p l a i n the negative findings. H o w e v e r , we do not b e l i e v e that m e n o p a u s a l status was a m a j o r c o n f o u n d e r o f the a s s o c i a t i o n b e t w e e n V E and M I since the a s s o c i a t i o n b e t w e e n m e n o p a u s a l status and V E was rather small. N o i n f o r m a t i o n was a v a i l a b l e about c u r r e n t cholesterol levels, b e c a u s e these were not usually m e a s u r e d in controls. Since V E is not a s s o c i a t e d with cholesterol in males [ 3 ] , we a s s u m e that the odds ratio w o u l d not have c h a n g e d a p p r e c i a b l y if cholesterol had been included in any o f the models. In sum, we c o n c l u d e that the o d d s ratio a s s o c i a t e d with V E is significantly elevated a b o v e 1.00. M o r e o v e r , given the c o r r e s p o n d e n c e with the o d d s ratios that were o b s e r v e d in e a r l i e r p r o s p e c t i v e and c a s e - c o n t r o l studies in males [2, 1 0 ] , we b e l i e v e that the estimate o f the absolute m a g n i t u d e o f 2.75 is rather fair. The m u l t i v a r i a t e analyses s h o w e d that the a s s o c i a t i o n b e t w e e n V E and M I was not due to e x h a u s t i o n being a side effect o f the somatic risk factors that w e r e included or o f manifest heart disease. It m a y be thought, h o w e v e r , that V E is a m a r k e r o f subclinical heart disease. Studies in male c o r o n a r y patients have shown that V E was not a s s o c i a t e d with left ventricular ejection fraction and was p r e d i c t i v e o f new c a r d i a c events in males after successful a n g i o p l a s t y , controlling for extent o f a t h e r o s c l e r o s i s [11 ]. T h e r e f o r e , we c o n s i d e r it unlikely that V E is a s s o c i a t e d with M I b e c a u s e it reflects sub-clinical heart disease. H o w e v e r , as long as the u n d e r l y i n g b i o c h e m i c a l o r p h y s i o l o g i c a l m e c h a n i s m ( s ) r e m a i n u n k n o w n , it m a y be prudent to refer to V E as a risk i n d i c a t o r instead o f a risk l:actor. The c o n c l u s i o n that V E p r e c e e d s M I does not seem to c o r r e s p o n d with s o m e o b s e r v a t i o n s m a d e in the F r a m i n g h a m Study. In that study a 300-item p s y c h o s o c i a l q u e s t i o n n a i r e was a d m i n i s t e r e d to 749 w o m e n , who subsequently w e r e f o l l o w e d during 20 yr. This questionnaire has three items which are to s o m e extent identical to s o m e questions o f the M Q , n a m e l y : ' c o m p a r e d to the w a y you were 10-years ago, are you: m o r e irritable, the same, less i r r i t a b l e ? ' ; ' D o you g e n e r a l l y sleep or fall asleep without trouble: yes, n o ? ' and (asked to h o m e m a k e r s only) ' h a v e you often felt tired and exhausted'?'. O f these three questions only the second one was predictive o f MI [ 12]. The difference b e t w e e n the o b s e r v a t i o n s m a d e in F r a m i n g h a m and in the present study is p r o b a b l y caused by the limitation o f the a s s e s s m e n t o f exhaustion by only

Exhaustion and infarction in women

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t h r e e i t e m s , w h i c h w e r e s e p a r a t e l y tested for t h e i r p r e d i c t i v e p o w e r . T h i s l o w e r s the r e l i a b i l i t y o f the m e a s u r e m e n t . A n i t e m a n a l y s i s o f the M Q s h o w e d that the i t e m ' d i d y o u o f t e n f e e l t i r e d ? ' did n o t d i s c r i m i n a t e b e t w e e n c a s e s and c o n t r o l s in this s a m p l e . In c o n t r a s t , the i t e m ' d i d y o u s o m e t i m e s feel that y o u r b o d y w a s l i k e a b a t t e r y that is l o s i n g its p o w e r ? ' d i s c r i m i n a t e d s t r o n g l y b e t w e e n c a s e s and c o n t r o l s . A n assessm e n t b y a n u m b e r o f q u e s t i o n s , e a c h r e f l e c t i n g a d i f f e r e n t r e p r e s e n t a t i o n o f the c o n s t r u c t to b e m e a s u r e d , i n c r e a s e s the r e l i a b i l i t y and c o n s t r u c t v a l i d i t y o f a scale. V E w a s f o n d to b e a s s o c i a t e d w i t h a n u m b e r o f b i o g r a p h i c a l c h a r a c t e r i s t i c s . All o f t h e s e w e r e p r e v i o u s l y f o u n d to be a s s o c i a t e d w i t h V E in adult m a l e s [10, 1 3 ] . T h e u n i q u e finding o f this study w a s the s t r o n g a s s o c i a t i o n b e t w e e n V E and h o l d i n g a j o b w h i l e s i m u l t a n e o u s l y t a k i n g c a r e o f the h o u s e h o l d . T h i s finding c o r r e s p o n d s w i t h the s t r o n g a s s o c i a t i o n b e t w e e n V E and p r o l o n g e d o v e r t i m e w o r k in m a l e s [ 1 2 ] . It is b e y o n d the s c o p e o f this p a p e r to d e s c r i b e the a s s o c i a t i o n s b e t w e e n the biog r a p h i c a l c h a r a c t e r i s t i c s and M I o b s e r v e d in t h e s e s a m p l e s . W e w o u l d o n l y l i k e to m e n t i o n h e r e that h a v i n g h a d such a ' d o u b l e j o b ' did n o t i n c r e a s e the r i s k for M I . H o w e v e r , the c o m b i n a t i o n o f h a v i n g a p a y i n g j o b and s i m u l t a n e o u s l y t a k i n g c a r e o f a h o u s e h o l d w h i c h i n c l u d e s c h i l d r e n y o u n g e r t h a n 16 y r o f a g e w a s a s s o c i a t e d w i t h an e l e v a t e d risk f o r first n o n - f a t a l M I in y o u n g e r w o m e n . REFERENCES 1. KULLERL. Prodromata of sudden death and myocardial infarction. Adv Cardiol 1978; 25: 61-72. 2. APPLESA, MULDERP. Fatigue and heart disease. The association between vital exhaustion and past, present and future coronary heart disease. J Psychosom Res 1989; 33: 727-738. 3. APPLES A, HOPPENER P, MULDER P. A questionnaire to assess premonitory symptoms of myocardial infarction. Int J Cardiol 1987; 17: 15-24. 4. ROSEGA, BLACKBURNH, GILLUMRF, PRINEASRJ. Cardiovascular Survey Methods Second Edn. Geneva: World Health Organization, 1982. 5. NoRusls M/SPSS INC. SPSS/PC 4.0. Chicago: SPSS. Inc, 1990. 6. CROYLE RT, SANDE GN. Denial and confirmatory search: paradoxical consequences of medical diagnosis. J Appl Soc Psychol 1988; 18: 473-490. 7. KANNELWB, HJORTLANDMC, MCNAMARAPM, GORDONT. Menopause and risk of cardiovascular disease: the Framingham Study. Ann Intern Med 1976; 85: 447-452. 8. COLDITZ GA, WILLETT WC, STAMPFER MJ, ROSNER B, SPEIZER FE, HENNEKENS CH. Menopause and the risk of coronary heart disease in women. N Engl Med 1987: 316: 1105-1110. 9. WITTEMANJCM. Increased risk of atherosclerosis in women after the menopause. Br Med J 1989; 298: 662-664. 10. FALGERPRJ. Life-span development and myocardial infarction: an epidemiological study. Ph.D. Thesis, University of Limburg School of Medicine, Maastricht, 1989. 11. KoP WJ, APPLES A, MENDES DE LEON CF, BAR FS, DE SWART H. Vital exhaustion predicts new cardiac events after PTCA--final results. (submitted) 12. LAKER ED, PtNSKY J, CASTELLIWP. Myocardial infarction and coronary death among women: psychosocial predictors from a 20-year follow-up of women in the Framingham Study. Am J Epidemiol 1992; 135: 854-864. 13. FALGERPRJ, SCHOUTENEGW. Exhaustion, psychological stressors in the work environment, and acute myocardial infarction in adult men. J Psychosom Res 1992; 36: 777-786.

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A. APPELS et al. APPENDIX

BIOGRAPHICAL CHARACTERISTICSTHAT WERE STUDIED WITH RESPECT TO THEIR POSSIBLE ASSOCIATIONS WITH

VITAL

EXHAUSTION

Childhood and adolescence: Being raised by one parent; Prolonged parental illness; Prolonged familial conflicts; Prolonged unemployment in family; Prolonged financial problems. Work: Ever holding a job; Worked for financial reasons only; Work place closed down; Holding a job and simultaneously taking care of the household; Holding a job and having children younger than 16 years of age; Holding a job during the last half year before hospitalization. Adulthood: Marital status; Unwanted childlessness; Prolonged/serious illness of children; Death of children; Prolonged/serious educational problems with children; Children leaving home; Prolonged/serious problems with children away from home; Raising children alone; Prolonged illness of spouse; U n e m p l o y m e n t of spouse; Conflicts at work of spouse; Prolonged/serious marital problems; Prolonged/serious illness or death of family members; Prolonged/serious financial problems.