association between stress and blood pressure variation in a caribbean population
TRANSCRIPT
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 71:69-79 (1986)
Association Between Stress and Blood Pressure Variation in a Caribbean Population
JANIS HUTCHINSON Department ofAnthropology, University of Houston, Houston, Texas 77004
KEY WORDS Psychosocial stressors
Variance, Arterial pressure, Life change,
ABSTRACT Based on the work of Selye (The Stress of Life, New York: McGraw-Hill, 1976) it is hypothesized that stress can produce physiological abnormalities, i.e., elevated blood pressure, and that social variables can be used as indicators or risk factors for disease. It is theorized that deviations from acceptable social patterns or traditional life-styles can produce stressful conditions that are associated with disease and that these situations can be demonstrated by examination of certain social characteristics. This association is examined among the Black Caribs of St. Vincent, West Indies. The social variables included in this analysis are marital status (single, married, wid- owed, or separated), frequency of church attendance (frequently, sometimes, seldom, or never), years of education, and number of children (for women only). The findings show that single individuals have higher pressures than married subjects and that males who never attend church have higher pressures than men who frequently attend church; a relationship was not demonstrated for females. Among males, as the years of education increased, blood pressure also increased, but for females, increased education was associated with lower pressures. Family size was not associated with systolic or diastolic pressure. The analysis of these selected social variables suggests that these variables influence male systolic and diastolic pressures, but only female diastolic pressure.
Disease can be caused by genetic factors and physiological abnormalities, e.g., ele- vated blood pressure. In the latter, some psy- chosocial factors may affect normal phys- iological functions and result in disease. In this instance, psychosocial factors do not cause disease but modify an individual’s re- action to a disease agent (Rabkin and Struen- ing, 1976). Selye (1976) called stimuli that produced stress “stressors” and proposed that the state of stress alerts physiological mech- anisms to meet the challenge imposed by stressors. Stressful situations can be created in a number of ways, such as nonconfor- mance to traditional values, overcrowding, aging, emotional deprivation, lack of group support, or not following a coping life-style (Henry and Casse1,1979). Sometimes the bod- y’s adaptive mechanisms fail to meet the challenge issued by stressors, and this re- sults in disease (Scotch and Geiger, 1963; Harris, 1980; Dressler, 1982). Short-term re- actions to psychosocial stressors may include
damaged physical performance and emo- tional changes because of increased secre- tions of catecholamines or corticoids, whereas long-term reactions may produce neurosis, social maladjustment, gastrointestinal disor- ders, thymus atrophy, and cardio-vascular disease (Selye, 1976; Harris, 1980).
Major life changes such as loss of a spouse or child, divorce, and retirement can be used to identify individuals who will develop my- ocardial infarction or coronary heart disease with the same accuracy as physical risk fac- tors such as high serum cholesterol level (En- gel, 1971). It has been shown, using Life Change Tests, that myocardial infarction subjects showed a significant life change unit build-up over the 2 years prior to their infarc- tion (Theorell and Rahe, 1971; Rahe et al, 1976). Rahe et a1 (1973) revealed that prior to sudden death, individuals reported high increases in life change, and delayed-death
Received November 19,1984; accepted February 18, 1986
01986 ALAN R. LISS, INC
70 J. HUTCHINSON
subjects reported less life change and survi- vors reported the lowest increases in recent life change events. Wolf (1969) and Bruhn et al. (1974) also found that persons with cer- tain personalities (e.g., type A-tireless striv- ing without satisfaction) are more susceptible to heart disease. Recent life changes may precipitate illness and death, which implies that if individuals had not been exposed to stressors the disease may not have developed.
Other studies have shown that deviations from acceptable social patterns or traditional life-styles can also produce stressful situa- tions and result in disease. These situations are produced because life-style expectations are high and may not be achieved while the psychological resources needed to cope with life-style stressors are unavailable (Dressler, 1982). Researchers have used certain social variables to indicate the presence or absence of stress. For instance, Koskenvuo et al. (1980) examined ischemic heart disease mor- tality rates by social class and marital sta- tus. The highest mortality was among wid- owed and divorced unskilled workers. These individuals also had a higher risk of sudden death than married people. Kraus and Lil- ienfeld (1959) examined mortality by marital status and found that mortality for all causes was lower among married people than sin- gle, divorced, and widowed individuals.
Stressful situations can also be created by failure to achieve the desired family size. Certain sociocultural practices are available in urban but not rural areas, and vice versa. Scotch (1963) reported that in the urban area, women with five or more children had a greater tendency for hypertension than women with four or less children. In tradi- tional rural Zulu society, however, having few children was associated with increased blood pressure. Miall et al. (1962) revealed that among urban Jamaicans, the preva- lence of diastolic hypertension was lower in those with moderate-sized families of two to five children; the prevalence of hypertension increased in those with large families.
Church attendance has also been associ- ated with the onset of illness. Scotch (1963) discovered that church attendance, in rural areas, was accompanied by normal blood pressure for males and females. However, in the urban environment, men who belonged to Christian churches had higher rates of hypertension than nonmembers; the opposite was true for women. Church attendance has also been positively correlated with emo-
duced anxiety about death (Moberg, 1956); Martin and Wrightman, 1965). In Israel, the Ischemic Heart Disease Project found a two- fold increase in the risk of first myocardial infarction among the nonreligious group (Comstock and Partridge, 1972). The risk of dying from tuberculosis, arteriosclerotic heart disease, emphysema, cirrhosis of the liver, and suicide were appreciably higher among infrequent church attenders. These studies seem to indicate that the association of church attendance is nonspecific rather than causal CYerushalmy and Palmer, 1959; Comstock, 1971).
Lastly, occupational level has been associ- ated with health status. Eliot (1979) reported that the personnel at the Kennedy Space Center in Florida were at unusually high risk for coronary heart disease and that it was associated with psychological stress. Higher rates were found among administra- tors, managers, and foremen than among the general employee population. Supervisors experienced stress that was manifested as anxiety and depression. Miall and Oldham (1958) also found higher blood pressures among men with sedentary or supervisory occupations than among those with manual jobs.
Hypertension is common among blacks in the United States, and coronary heart dis- ease is the leading cause of death in this group (Labarth, 1976; Hypertension Detec- tion and Follow-up Program, 1977; Dischin- ger et al, 1981; Gillum, 1982). Although the prevalence of hypertension is high among blacks in the United States, black popula- tions in Africa and descendants of West Afri- can blacks do not always follow this pattern (Donnison, 1929; Shaper, 1972; Etta and Wat- son, 1976; Miller et al., 1982; Khaw and Rose, 1982). For example, Shaper and Saxton (1969) found that rural tribesmen in Uganda had lower mean pressures than U.S. blacks, and on St. Lucia, in the Caribbean, only 10% of the men and 9% of the women were hyper- tensive compared to 22% among US. blacks (Dischinger et al., 1981; Khaw and Rose, 1982). There are other areas in Africa and the Caribbean where the prevalence of hy- pertension is high: Jamaica, St. Kitts, and urban Nigeria (Schneckloth et al., 1962; Miall et al., 1962; Akinkugbe and Ojo, 1969). Hy- pertension may be more prevalent in these populations because socioeconomic and socio- cultural chanze have taken dace in the rel- atively newly-formed black iopulations. The
tional adjustment in old age and with re- Black Caribs of St. Vincent, West Indies, are
71 STRESS AND BLOOD PRESSURE VARIATION
descendants of African slaves and therefore present an opportunity to examine the af- fects of changed life-styles on health status, i.e., elevated blood pressure. It is theorized that individuals who adhere to the norm ex- hibit lower pressures than individuals who are considered deviant by society and by themselves.
MATERIALS AND METHODS
Demographic, anthropometric, and blood pressure data were collected on St. Vincent Island, West Indies. Households were se- lected at random, and their members were interviewed. Information was gathered from 144 males and 213 females; their ages ranged from 18 to 92 years old. Using a question- naire, demographic data were gathered on age, sex, ethnicity, church attendance (fre- quently was considered to be every Sunday to two times a month; sometimes was once a month; seldom was a few times a year; and never), marital status (single, married, wid- owed, or separated; none of the subjects was divorced), educational level, and total fertil- ity. Fertility information was collected for women only; only females over 45 years of age are included in the analysis of variance.
Two blood pressure readings were taken for each individual and were averaged for the analyses. Subjects were seated for ap- proximately 5 minutes prior to blood pres- sure determination and were informed as to the nature of the study and the measurement technique. Blood pressure readings were taken while subjects were seated with their left arm resting on a table. A baumanometer with a 14 cm wide compression cuff was po- sitioned on the left arm at heart level, and systolic and diastolic (phase V) pressures were then measured and recorded. Individu- als were questioned about medication, kid- ney malfunction, and diabetes mellitus, because these conditions can modify blood pressure. Information concerning these health problems was asked for on the ques- tionnaire and was provided by the nurse and doctor on St. Vincent (22 individuals were excluded because of these factors).
Average blood pressure readings were standardized to remove the effects of age, sex, and weight befcxe examining the rela- tionship between stress and blood pressure. First, the data were partitioned by sex, and then blood pressure was regressed on weight and age. The standardized residuals from the regression analyses were used as the depen- dent variable in the analvses. The values
presented in the ANOVAS are the mean standardized values and can be interpreted like raw means.
Analysis of variance (SPSS) was used to assess the effects of one or more independent variables (marital status, frequency of church attendance, family size, and educational level) on blood pressure, the dependent vari- able. Single classification analysis of vari- ance only gives the combined effects of the independent variables (social traits) on the dependent variable (blood pressure). This is the F value or ratio. It determines if the combined effect of the independent variables significantly influence the dependent vari- able. The Tukey test was used to determine which categories of the independent vari- ables significantly modify the dependent variable (Sokal and Rohlf, 1969; Nie et al., 1975).
RESULTS
Table 1 provides the mean systolic pres- sures for males and females by age group for each social category. Examination of marital status by age cohort indicates that male sys- tolic pressure is lowest in the married group for the youngest and oldest age groups, while female systolic pressure is lower in the mar- ried group except in the 46-65 age range. When considering educational level, as age increases among males, the number of years of education decreases. Individuals with 6- 10 years of education possess low pressures except in the oldest age category. Female pressure exhibits a similar trend, with the 6-10 year group presenting low values. Church attendance among males reveals that the seldom and never categories have the lowest pressures except in the 36-45 age group. Females demonstrate the opposite with either the lowest pressures exhibited in the frequently or sometimes categories or the absence of individuals in the seldom or never group in the older age categories. Examina- tion of family size among females reveals that young women with 0-1 child have low pressures, but between the ages of 26-45 years females with 2-4 children have the lowest pressures. After 36 years of age fe- males with large families have the lowest pressures compared to other females in the same age group.
When considering diastolic pressure, there is considerable fluctuation between single and married males by age group (Table 2). Bv contrast. females exhibit lower Dressures i n the married group except in tLe 26-35
TAB
LE 1
. Mea
n sy
stol
icpr
essu
re b
y so
cial
cat
egor
y, a
ge, a
nd s
ex
Age
gro
ups
18-25
SD
26-35
SD
36-45
SD
46-55
SD
56-65
SD
66 +
SD
Mar
ital s
tatu
s
Sing
le
Mar
ried
W
idow
ed
Fem
ale
Sing
le
Mar
ried
W
idow
ed
Sepa
rate
d E
duca
tion
bear
s)
Mal
e
Mal
e 0 1-5
6-10
11-15
16-21
Fem
ale
0 1-5
6-10
11-15
16-21
Chu
rch
atte
ndan
ce
Fre
quen
tly
Som
etim
es
Seld
om
Nev
er
Fem
ale
Fre
quen
tly
Som
etim
es
Seld
om
Nev
er
Fam
ily s
ize
Fem
ale
0 1 2-3
4
Mal
e
116.27
110.66
104.43
103.42
114.25
111.66
213.00
103.92
101.20
127.70
122.00
114.88
111.22
104.06
101.50
105.66
102.88
102.14
103.86
107.46
106.00
18.69
3.05
7.62
9.64
10.61
8.71
0.00
6.91
3.63
31.93
0.00
12.88
7.73
6.61
5.97
8.47
6.33
6.53
7.73
7.53
8.48
115.33
117.66
108.87
105.75
115.90
108.12
102.00
110.00
117.33
113.80
117.00
104.90
109.00
107.77
114.66
114.50
109.50
106.72
106.00
9.66
6.25
13.90
9.74
8.03
12.93
0.00
0.00
8.91
7.80
10.69
9.14
1.41
17.15
14.89
20.68
14.82
11.10
11.02
114.00
114.16
119.00
115.00
114.80
114.00
136.00
115.47
110.85
124.00
116.44
106.00
117.26
114.00
116.00
122.00
122.00
137.00
108.33
117.17
6.57
7.15
13.00
19.88
8.06
0.00
0.00
16.71
4.74
0.00
6.69
0.00
19.61
0.00
13.16
0.00
0.00
21.21
11 -4
1
119.00
124.13
134.66
127.05
120.00
123.00
123.60
136.85
123.75
124.15
114.00
129.50
116.00
134.00
16.69
24.14
29.65
18.26
0.00
1.41
42.83
30.26
16.47
26.22
8.48
22.55
5.65
0.00
124.92
134.50
132.84
120.50
128.00
142.00
127.00
144.00
106.00
148.00
124.00
130.00
122.00
120.00
102.00
132.85
124.00
125.33
15.15
9.14
25.23
18.35
0.00
0.00
21.21
0.00
0.00
0.00
15.20
16.10
0.00
8.00
0.00
23.81
10.58
11.54
34.69
18.00
25.59
138.00
133.84
142.00
144.66
134.50
157.33
131.00
160.00
162.00
142.00
131.00
112.00
134.36
137.00
130.00
142.00
178.00
0.00
17.21
11.31
11.01
19.67
52.62
26.87
0.00
0.00
0.00
18.38
0.00
18.90
8.40
18.83
11.31
50.91
TAB
LE 2
. Mea
n di
asto
lic p
ress
ure
by s
ocia
l cat
egor
y, a
ge, a
nd s
ex
Age
gro
ups
18-2
5 SD
26
-35
SD
36-4
5 SD
46
-55
SD
56-6
5 SD
66
+ SD
Mar
ital s
tatu
s
Sing
le
Mar
ried
W
idow
ed
Fem
ale
Sing
le
Mar
ried
W
idow
ed
Sepa
rate
d E
duca
tion
bea
rs)
Mal
e
Mal
e 0 1-
5 6-
10
11-1
5 16
-21
Fem
ale
0 1-5
6-10
11
-15
16-2
1 C
hurc
h at
tend
ance
Fre
quen
tly
Som
etim
es
Seld
om
Nev
er
Fem
ale
Fre
quen
tly
Som
etim
es
Seld
om
Nev
er
Fam
ily s
ize
Fem
ale
Mal
e
0 1
2-3
4 5-10
77.5
0 66
.66
69.5
0 69
.42
74.7
1 71
.33
168.
00
69.5
6 66
.00
88.2
0 72
.00
72.6
6 73
.77
69.4
3 70
.00
68.1
6 72
.00
68.5
7 67
.73
73.6
0 73
.00
23.4
9 11
.01
8.86
12
.63
10.7
5 2.
42
0.00
8.53
13
.78
44.2
7 0.
00
10.4
4 7.
44
8.81
6.
53
11.6
1 8.
06
8.42
9.
36
8.25
7.
07
79.7
1 83
.66
72.0
8 73
.00
77.7
0
72.2
5 68
.00
74.0
0
82.3
3 76
.20
82.5
0
68.6
0 76
.00
73.5
5 81
.66
75.0
0 64
.50
74.5
4 73
.05
10.8
8 11
.69
13.5
3 6.
92
10.8
0
11.7
8 0.
00
0.00
13.2
3 12
.34
8.40
7.97
5.
65
14.1
3 13
.41
11.6
0 6.
80
12.9
9 9.
85
80.3
3 77
.00
85.4
0 75
.88
77.8
0 78
.00
78.0
0 78
.84
74.5
7 90
.00
81.1
1 64
.00
78.0
0 74
.00
82.2
8 10
0.00
100.
00
87.0
0 72
.33
79.6
4 71
.00
8.89
7.
45
14.4
8 13
.93
7.45
0.
00
0.00
14
.88
7.89
0.
00
4.59
0.
00
14.2
3 0.
00
14.7
1 0.
00
0.00
7.
07
15.5
1 14
.12
9.89
81.0
0 83
.46
91.0
0 83
.64
82.0
0
69.0
0 83
.20
92.2
8
82.2
5
83.8
4
76.0
0
86.1
0 85
.00
76.0
0
84.5
0 96
.00
86.0
0 78
.00
12.3
8 17
.07
16.3
8 11
.55
0.00
1.41
28
.02
13.9
7
10.7
1
17.6
7
12.6
4
13.6
1 9.
89
0.00
8.06
23
.58
10.7
5 2.
82
72.0
0
83.5
0 78
.73
86.5
0 90
.00
60.0
0 69
.00
80.0
0
78.0
0 96
.00
74.2
0
71.5
0 68
.00
74.0
0 74
.00
81.3
3 80
.00
81.3
3 80
.66
71.6
6 85
.83
82.0
0
6.58
11.3
5 11
.35
18.2
8 0.
00
0.00
1.
41
0.00
0.00
0.
00
9.77
7.83
0.
00
5.92
0.
00
13.3
3 10
.58
7.57
10
.06
9.50
14
.05
14.1
4
74.0
0 79
.07
88.0
0
70.6
6 78
.75
90.0
0
86.0
0 78
.00
70.0
0
78.0
0 61
.00
70.0
0
80.1
8
81.5
0
72.2
8 88
.00
90.0
0
73.0
0 73
.00
76.8
0 82
.66
0.00
10
.21
5.65
11.7
1 9.
67
13.1
1
8.48
0.
00
0.00
0.00
1.
41
0.00
11.2
5
5.26
11.2
8 0.
00
16.9
7
15.5
5 9.
89
12.0
5 8.
32
74 J. HUTCHINSON
year and 66 + age categories (Table 21.' Males have the lowest pressures in the 6-10 year education level except in the 18-25 and 46- 65 age groups. Among females, as the num- ber of years of education increases, diastolic pressure decreases for almost every age group. For church attendance, the lowest pressures are in the seldom and never cate- gories for younger and middle-aged males, while the oldest males exhibit low pressures in the frequently to sometimes categories. Females exhibit low pressures in the fre- quently category for almost every age cohort. For family size, females with 0-1 child show low pressures in the younger age groups, but as age increases the lowest pressures are in the 2-3 children category except for the 46- 55 age group. As expected, blood pressure increases with advancing age, and there are differences in both systolic and diastolic pres- sures within the various social categories.
Table 3 examines the association between pressure and social categories after standard- izing for age and weight. Analysis of vari- ance for males computed an F ratio of 46.255 and 29.828 (df = 2,133) for systolic and dia- stolic pressures, respectively. The Tukey test demonstrates a significant divergence be- tween all possible pairs of groups, with single subjects having the highest pressures fol- lowed by married and widowed males.
Higher adjusted pressures among single males are not due to increased weight or stature in this group. The average weight for single males is 142.7 kg and for married males it is 145.1 kg; for widowed males the average is 128.5 kg. The average stature for single males is 175.4 cm and for married males it is 168.4 cm; for widowed males the average stature is 167.6 cm. Although mean stature is higher among single males, it is not significantly different from the mean for married males (P = 1.149, df = 132).
Female systolic pressure does not provide similar results. The F value is not significant (F = 0.568, df = 3,197). Female diastolic pressure, however, reveals a significant F value (F = 9.243, df = 3,1971, and the Tukey test shows that married women have the low- est mean adjust pressures (Table 3).
Higher pressures among single women are not due to increased weight or stature in this marital category. Mean weight is higher in the married (142.3 kg) than single (131.0 kg) group; mean weight for the widowed group is 121.7 kg. Statures are similar in the sin- gle, married, and widowed cohorts (157.1 cm, 155.7 cm, and 157.4 cm, respectively).
Analysis of variance for educational cate- gories reveals a significant F value for male systolic and diastolic pressures (F = 14.795 and 26.5, respectively; df = 4,137) (Table 3). Males with more than 6 years of education exhibit higher mean pressures than males with 0-5 years of education.
Female systolic pressure does not present the male pattern Crable 3). The F value (F = 0.807, df = 4,210) is not significant. For dia- stolic pressure, however, the F ratio (F = 4.342, df = 4,210) is significant. Females with more than 6 years of education or with 0 years of education possess lower mean dia- stolic pressures than the 1-5 year cohort.
For church attendance, males have a sig- nificant F value for both systolic and dia- stolic pressures (F = 5.117 and 3.418, respectively, df = 3,121) (Table 3). The Tukey test demonstrates a significant difference be- tween males who frequently attend church and males who never attend, with the latter exhibiting higher mean adjusted pressures.
Females do not exhibit a similar pattern for either systolic or diastolic pressure. The F value for systolic pressure (F = 0.632, df = 3,177) is not significant, and the Tukey test does not reveal a significant divergence in mean systolic pressure between categories of church attendance. In addition, the F value (F = 0.436, df = 3,177) for diastolic pressure is not significant. Again the Tukey test does not present significant deviations between groups.
Examination of female systolic and dia- stolic pressures do not demonstrate a rela- tionship with completed family size. The F ratios for systolic and diastolic pressures (F = 1.359 and 1.111, respectively, df = 4,69) are not significant. Also, the Tukey test does not reveal significant distinctions in adjusted mean pressures between categories of family size.
DISCUSSION AND CONCLUSIONS
Stress created by the cultural environment can be associated with physiological abnor- malities. Pathologies such as hypertension, arthritis, and gastrointestinal ulcers have been induced in experimental animals by ex- posing them to intense stimuli. Selye (1976) hypothesized a mechanism for this process. He stated that a n unknown alarm signal acted through the floor of the brain to stim- ulate the sympathetic nervous system and the pituitary gland. Anthony and Kolthoff (1975) suggested that one of the first re- sponses to stress of the body is an increase in
TA
BL
E 3
. Sta
ndar
dize
d m
eans
and
Tuk
ey te
sts f
or a
rter
ial p
ress
ure
by s
ex a
nd s
ocia
l cat
egor
ies
Mal
es
Fem
ales
(dia
stol
ic)
Dia
stol
ic
Tuk
ey te
st
~
Tuk
e te
st
Tuk
ey te
st
Syst
olic
No.
M
ean
Sing
le
Mar
ried
N
o.
Mea
n Si
ngle
M
arri
ed
No.
M
ean
Sing
le
Mar
ried
M
arit
al s
tatu
s *
* Si
ngle
72
3.
8286
72
2.
5644
10
7 -5
.531
7 *
-0.0
565
85
-7.9
995
8 0.
8423
W
idow
ed
2 -1
4.76
33
2 -1
.336
2 *
* Se
para
ted
1
-1.3
343
* *
* M
arri
ed
62
-2.3
610
62
Yea
rs o
f Y
ears
of
Yea
rs o
f ed
ucat
ion
Edu
catio
n E
duca
tion
0
1-5
0 1-
5 6-
10
11-1
5 6-
10
Yea
rs o
f edu
catio
n 0
60
-2.2
898
1-5
4 -5
.069
9 6-
10
69
3.27
03
* 11
-15
8 3.
3948
*
16-2
1 1
12.6
690
*
* * *
60
0.44
15
83
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76 J. HUTCHINSON
sympathetic activity. Sympathetic fibers in- nervate blood vessels and stimulate the se- cretion of epinephrine, which tends to increase blood sugar, blood pressure, and heart rate. Sympathetic fibers also innervate the heart where they release norepinephrine, which accelerates the heart rate (Guyton, 1979). Kong (1984) stated that the net re- sponse of the body to stressful situations is temporarily to increase cardiac output, vas- cular constriction, and fluid retention. For many individuals this process is repetitive and chronic.
Hypertension is more prevalent among in- dividuals who deviate from social prefer- ences, for example, victims of racism or classism, and is less frequent among those who meet or exceed the norm (Kong, 1984). Individuals who are susceptible to high blood pressure are frustrated because they cannot achieve the goals attained by in-group people and are in a constant state of disharmony. The social life of such individuals is charac- terized by social anxiety, a distrustful atti- tude toward others, and a negative expectancy toward people (Kong, 1984). This type of vicious cycle is a strain on the body and can result in disease. Hypertension is one of the many physical illnesses that can be produced by this process.
Deviation from acceptable or expected pair bond relationships may cause disharmony and result in illness. The “Christian family” which consists of a legally married couple and their children, is the desired or ideal mating pattern in the Caribbean (Lowen- thal, 1972; Dressler, 1982). In Barbados 70% of the men are married by the age of 30, and the proportion of ever married is high (Cum- per, 1961). This relationship is stable, pro- vides security, and represents social achieve- ment for both husband and wife. It is also a symbol of economic prosperity, because men do not marry until they possess sufficient wealth to support a family (Simey, 1946; Greenfield, 1961; Solien, 1971; Lowenthal, 1972).
When the effect of age and weight are re- moved, married individuals have lower pres- sures. One hypothesis that may account for this situation is that married individuals form a social support group. These individu- als comfort one another during critical pe- riods of their lives and have the psychological resources to cope with stress. Married people have followed traditional values while single individuals have not, and the latter may con-
sider themselves deviant or may believe that society views them as such. In addition, sin- gle individuals lack a support network, which may make it difficult for them to cope with stressful life events. Married people have also achieved an important goal in their life cycle and may be satisfied with their status. Mar- riage indicates that these individuals have accomplished certain goals in life, for exam- ple, women expect a showy wedding, a better home, a maid, and full economic support without having to work (Greenfield, 1961; Laufer, 1973). This also means that men have achieved a higher status and have more eco- nomic wealth. Men are now able to fulfill obligations to their wife, children (which may have been conceived prior to marriage), and possibly parents as well. Because of the ac- cumulation of a certain amount of economic wealth, these individuals have prestige in the community and may have a better life than single and widowed people. Last, mar- riage may reduce stress because of the impor- tance of marriage in the church. The vast majority of people on St. Vincent are Angli- cans, and the church plays an important role in their lives (Lowenthal, 1972). Marriage indicates that they are following the teach- ings of the church, which may further in- crease their prestige within the community. It is not merely the attainment of prestige that reduces stress, but the knowledge that social norms have been achieved.
Another social variable, educational sta- tus, presented contrasting results between males and females. For males, as the years of education increased, blood pressure also increased. Educated people are looked up to, because it is believed that they understand and can interpret the complex world (Dres- sler, 1982). West Indians especially want their sons to be educated and to acquire white-collar jobs so they can provide for their parents in old age (Laufer, 1973; Toran, 1973). As a result, elevations in pressure with in- creased education was not expected. In- creases in pressure among the highly educated may be due to greater responsibili- ties being placed upon males because they are educated, have better jobs, and may be the only educated member of their family. Therefore, their parents may expect them to be more supportive financially and to take a leadership role in the household as far as family affairs are concerned. Of all the sib- lings, they are expected to take care of their parents and their wife and children.
STRESS AND BLOOD PRESSURE VARIATION 77
The Detroit Project Study (Harburg et al., 1973) included educational level in their def- inition of low versus high stress area. They found that blacks in high stress areas (low educational level) had higher pressures than blacks in low stress areas (high educational level). It should also be stated that the deter- mination of the type of stress area was also based on other factors such as type of hous- ing and frequency of crime. These factors may contribute to variation in blood pressure level. The prediction was also based on U.S. culture, where education is inversely associ- ated with hypertension (U.S. Department of Health, Education, and Welfare, 1964; Stam- ler et al., 1967; Hypertension Detection and Follow-up Program, 1977). Although such cultural patterns are desired or achieved, other factors may play a part in creating stressful situations. For instance, Smith (1960) found that in rural Jamaica young boys had a preference for professional work, while older boys wanted mechanical jobs. For these individuals professional careers are un- likely, and mechanical work is usually un- available. There is a gap between reality and desire; and even if they should receive an advanced education, job opportunities are lacking. More than likely they will not be able to use their skills and may have to ac- cept a less prestigious occupation. The inabil- ity to achieve the expected economic level may produce stress and result in elevated blood pressures.
Females in the 6-10 year education cohort exhibit lower pressures than those without any education. This trend may indicate that St. Vincent is in a transitional stage regard- ing education for women. Although West In- dians believe that women should be wives and mothers and should not work, many women are now becoming nurses, bank tell- ers, and teachers (Laufer, 1973). This change (from remaining in the household and receiv- ing little education to becoming highly edu- cated working women) has probably taken place over a relatively long period of time, and women have adapted to their new life- styles. Therefore, they are following modern norms, have not created stressful situations by acquiring a n education, and have low blood pressures.
Religious doctrine is fundamentalist in the Caribbean. Religion is more relevant to everyday life, and church attendance is more regular (Lowenthal, 1972). Since most Vin- centians are members of the Anglican
Church, it was predicted that individuals who frequently attend church have lower pres- sures than those who do not attend. This hypothesis is supported for both systolic and diastolic pressures among males. The com- munities studied on St. Vincent are rural and follow the rural pattern revealed by Scotch (1963) among the Zulus of South Af- rica. On St. Vincent, conformity to tradi- tional rural values may contribute to low arterial pressures. In addition, church mem- bers may have lower pressures because they have a support network. Therefore psycho- logical resources needed to cope with life- style stressors are always present and may prevent the occurrence of a crisis situation. Such individuals may also be more satisfied with themselves and be better able to accept conflict because of their religious beliefs.
Frequency of church attendance does not influence female arterial pressure. Overall, 90.5% and 83.3% are classified as normoten- sives for systolic (< 140 mm Hg) and dia- stolic (< 90 mm Hg) pressures, respectively. In addition, 73.5% frequently or sometimes attend church. A lack of interaction between frequency of church attendance and arterial pressure may be due to the fact that the vast majority of women do attend church and these women do have normal pressures. Therefore, there was not enough deviation to demonstrate that variation in blood pressure is related to frequency of church attendance.
It is usually believed that West Indians want a large family to prove the man’s viril- ity and the woman’s femininity. Laufer (1973) stated that 76% of Jamaican women wanted four or less children compared to 87% of American women. On St. Vincent the aver- age number of children is six, and in the Caribbean the average is eight (Laufer, 1973). Therefore, there is a discrepancy between the ideal and reality. Large families may be the cultural norm because of the unavailability of birth control and widespread belief in the Due Number Theory, which states that God put a certain number of children in a wom- an’s body and it is her duty to have all of them (Laufer, 1973). The absence of a rela- tionship between completed family size and arterial pressure may suggest that number of children is not important on St. Vincent or that a large family is the accepted cultural pattern.
There were differences in pressures be- tween social categories by sex and age. It seems likely that adherence to social norms
78 J. HUTCHINSON
is age and sex dependent. At various ages individuals are expected to achieve certain goals. This is most striking for church at- tendance. Among males, the lowest pres- sures are in the seldom and never categories for younger and middle-aged males, while the oldest males exhibit low pressures in the frequently and sometimes categories. This follows the findings of Martin and Wright- man (19651, who found that church attend- ance was associated with emotional adjustment in old age. Younger males are not concerned with death and are not preparing for it. Also, for family size, pressures appear to conform to what is expected of females in each age category. Removal of the effects of sex and age (also weight, which causes pres- sures to vary) leaves variation in blood pres- sure level caused by other factors such as social stressors. Even after removal of varia- tion caused by age, sex, and weight there are significant differences in blood pressure lev- els among the social categories. This may demonstrate the importance of these social variables in determining blood pressure.
The present analyses present associations between arterial pressure and certain social traits. Modification of blood pressure level as a result of stressful social factors has not been proven, although it is suggested. Lack of demonstrated causation along with small sample size, for certain cohorts, and con- founding variables create problems in inter- preting the results. However, it seems likely that the variables examined in this study are stressors when individuals must function outside the normal limits of acceptance and are not able to cope with sociocultural de- mands. If these variables are accepted as stressors then the statistical significance demonstrated here also reveals a biological relationship between blood pressure and these social traits. These characteristics can then be viewed as risk factors for disease similar to physiological risk factors.
A major problem in understanding the etiology and epidemiology of arterial pres- sure is determining the contribution of ge- netic versus environmental influences. Both components have been extensively examined by a number of researchers (Lowe, 1964; Langford et al., 1968; Havlik et al., 1979; Canessa et al., 1980). The environmental ef- fects are difficult to assess since a large num- ber of external fadors may be involved; social variables are a factor in the environmental component. In a complex society, such as in the United States, stressors are a normal
part of everyday life and must be considered when identifying the etiology of disease. Hy- pertension is common among black Ameri- cans, in some populations in the Caribbean, and in Africa, but it is not prevalent in all African and Caribbean populations. The cause of this discrepancy may shed light on the sociocultural and psychosocial compo- nent of blood pressure variation. Research is needed to determine if these types of stres- sors differ among black Americans, Africans, and West Indians. Also, an examination of blood pressure level among black Americans who differ in these social variables may aid in demonstrating the role of these factors in the etiology of hypertension among black Americans. Other social factors specific to this population may also be discovered and collectively used to identify individuals at high risk for hypertension.
ACKNOWLEDGMENTS
This research was supported by General Research Fund #3156 at the University of Kansas, Lawrence, Kansas.
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