The Influence of Standard of Living
on Blood Pressure in Fiji
By
IAN MADDOCKS,
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THE HURRY and worry that accompany
Western civilization are often invoked as
etiologic factors in hypertension. In Fiji and
the Gilbert Islands some populations do not
show the higher blood pressures of later life
characteristic of Western populations.1 It is
tempting to associate the apparently indolent,
secure, and unhurried life of the Pacific
Islander with this relative freedom from
hypertension.
To test the possible influence of the "Western" way of life among these Pacific populations, I set out to compare in the same race
the blood pressures of a middle-aged group
that had led such a life, with a group that
had not. Few Fijians and hardly any Gilbertese lead "Western" lives, but there is
such a group among the Indians of Fiji. The
rural Indian population of Fiji has been studied and shown to have an incidence of high
blood pressure almost as low as among Fijians.2 There are numbers of Indian men in
business and the professions in Fiji, whose
wealth and influence are increasing. Most of
them have lived in relative physical comfort
compared with the rural Indians. They have
been concerned with clerical work rather than
manual labor, and have accepted the strains
of business competition. It is a common
prejudice among members of this group that
they suffer from high blood pressure, because,
they say, high blood pressure is associated
with worry and with drinking alcohol.
During March 1960, a survey of casual
arterial pressure was conducted among the Indian business men of Suva, Fiji, to compare
M.B.
them with the blood pressures of the previously reported rural population.
Methods
Selection of Subjects
The sample sought comprised shopkeepers (general merchants, jewelers, tailors), transport and
building contractors, and professional men (doctors, lawyers, insurance agents, teachers). To avoid
a selection that might have been conditioned in
any way by the health of the subjects, lists were
obtained from the two Indian Clubs of all members thought to be over 40 years of age, and from
the Civil List of all men over 40 years of age
earning more than F£500 annually, and all head
teachers. A total of 146 names was collected, and
of these 121 are included in the final sample. The
remaining 25 either could not be located in Suva
or were seen under circumstances that did not
satisfy the criteria for the standard measurement
of blood pressure. The Indians of Fiji originally
came from many different parts of India. The
genetic background of this urban sample was
mixed, but is thought to be very similar to the
genetic background of the rural sample with which
comparison is made.
Measurement of Blood Pressure
The technic of measuring blood pressure and
arm circumference has been described in detail
elsewhere.2 Both this survey and that of the rural
sample were conducted by the same observer. Subjects were visited in their offices or shops, and were
kept seated for at least 10 minutes before the
blood pressure was recorded.
Results
Mean systolic and diastolic pressures for
this group of urban Indians are compared
with those previously reported for rural Indians in table 1. Figure 1, which illustrates
the comparison, shows that the means of both
systolic and diastolic pressures of the urban
population were consistently higher than
those of the rural population. The significance
of this difference was investigated by comparing the linear regressions of blood pressure
From the University of Melbourne Department
of Medicine, Royal Melbourne Hospital, Victoria,
Australia.
Supported by grants from the Victor Hurley Medical Research Fund, Royal Melbourne Hospital, and
the Nuffield Foundation.
1220
Circulation. Volume XXIV, November 1961
STANDARD OF LIVING AND BLOOD PRESSURE
1221
Table 1
Arterial Pressure (mm. Hg) of Rural and Urban Indian Men
Age Number
30-39
394
40-49
448
50-59
187
60-69
179
RURAL
Systolic
Diastolic
Standard
Standard
Mean deviation Mean deviation
121.3
126.1
134.1
14.0
18.8
26.2
135.9
24.1
77.4
79.4
81.3
77.9
11.6
13.4
15.4
11.2
URBAN
Systolic
Number
Mean
Standard
deviation
18
55
39
9
126.1
130.1
140.1
145.0
20.5
20.5
21.6
22.2
Diastolic
Standard
Mean
deviation
88.1
87.0
88.6
88.3
12.6
14.3
12.8
8.6
Table 2
Arterial Pressure Corrected for Arm Circumference in Rural and Urban Indian Men
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Age
Arm
circumference
30-39
40-49
50-59
60-69
26.6
26.3
25.7
24.2
RURAL
Corrected
systolic
Corrected
diastolic
Arm
circumference
URBAN
Corrected
systolic
Corrected
diastolic
123.3
128.7
137.4
141.2
69.7
72.1
74.4
72.1
27.9
27.7
27.5
26.6
127.2
131.2
141.0
147.2
79.4
78.3
79.5
80.6
on age in the two populations by means of an
analysis of covariance. The regressions for
both systolic and diastolic pressures were
significantly different in level but not in slope
in the two samples.
Table 2 compares the mean arm circumferences in the two populations, and shows the
effect of applying the correction for arm circumference recommended by Pickering, Roberts, and Sowry.3 The urban Indians had
greater mean arm circumferences at all ages,
but the differences between the corrected
means remained significant, though reduced.
Discussion
For a systematic and significant difference
to occur between the blood pressures of two
populations, there need not be any way in
which they can be contrasted. Boe, Humerfelt, and Wedervang4 in their survey in the
City of Bergen, found such a difference between the two halves of that apparently homogeneous city. Here, therefore, where two
populations have been chosen to contrast in
their way of life, the differences found in
their blood pressures do not necessarily depend upon that contrast, but could oecur from
chance, or from the operation of other facCirculation, Volume XXIV, November 1961
tors. The almost universal concern shown by
the urban Indians about the level of their
blood pressures, for example, may have been
a sufficient emotional stimulus to raise their
pressures above those of the rural population,
who were generally less aware of the significance of blood pressure. This would have its
effect more upon the systolic pressure, and
the fact that the diastolic pressure is also significantly higher in the urban group probably
means that the emotion is not the cause of the
blood pressure difference.
A factor that might be responsible for the
difference is body weight. The increase of
blood pressure with body weight has been
demonstrated in many races. Padmavati and
Gupta5 found that the average systolic and
diastolic pressures of a group of urban Indians were higher than a poorer rural group,
and noted that the urban group had higher
average body weights. Body weight was not
measured in both the Indian population samples in Fiji, but its influence can be assessed
from the measurements of arm circumference.
From data available for part of the rural Indian population it has been calculated that an
increase of 1 cm. in arm circumference is
associated with an average increase of 3.7 Kg.
MADDOCKS
1222
INDIANS
150
* WEALTHY URBAN
o RURAL
I4O
.0---0
Table 3
Prevalence of Hypertension in Men Aged 40 to
69 Years
I-
a: 130
&120
W
a: IIC
SYSTOLIC
,___~-
Race
Gilbertese
Fijian
Rural Indian
Urban Indian
Londoners
0'
£xI9C
Lil
*
Wd 7C
*
'
AST
~~~DIASTOLIC
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<6C
a
.
I5
25
.
*
35
45
AGE (years)
*
55
a
65
75
Figure 1
The relationship between mean systolic and diastolic pressures and age for wealthy urban and
rural Indian men in Fiji.
in body weight. The average difference between the arm circumference of the two Indian samples (1.6 em.) therefore represents a
difference of approximately 6 Kg. in their
average body weights. B0e, Humerfelt, and
Wedervang4 estimated that an increase of 10
Kg. in body weight was associated with an
increase of 3 mm. Hg in systolic pressure and
2 mm. Hg in diastolic pressure. Weight differences between the two Indian populations,
on those figures, are too small to explain the
differences in their average blood pressures.
Table 3 compares the prevalence of systolic
pressures greater than 180 mm. Hg and diastolic pressures greater than 100 mm. Hg in
Fijians,2 Gilbertese,' the two Indian populations, and a London population" of men aged
40 to 69 years. The levels 180 and 100 mm.
Hg were chosen because they are often taken
in defining high blood pressure. The percentage of high pressures is least in Gilbertese,
and gradually increases through Fijians. rural Indians, urban Indians, and Europeans.
As the blood pressures of more racial groups
are studied, it will probably become apparent
that there is a continuous gradation from
Diastolic pressures
Systolic pressures
180 mm. Hg and over 100 mm. Hg and over
Number Percentage Number Percentage
1
15
32
4
29
0.05
2.8
3.9
3.7
6.8
11
39
76
25
53
5.5
7.3
9.3
22.6
12.5
those populations in which essential hypertension is rare (e.g., Gilbertese) to those
among whom it is a major disease and cause
of death (e.g., Europeans). That two groups
of Indians, apparently similar except for the
Western way of life of one of them, form a
step in this gradation, and that the influence
of Western culture among these peoples parallels the incidence of high pressures among
them, suggests that some environmental factor
or factors associated with the Western culture
pattern causes blood pressure to rise.
The sorting out of the possible operative
influence in the Western culture pattern is a
matter of great complexity. Diet, alcohol intake, exercise, and the frequency of psychologically stressful situations may all be relevant. Even if the inheritance of essential
hypertension is eventually defined in terms of
a single gene system, environmental factors
could still have important triggering effects.
The continuing study of population samples
in poorer countries where hypertension is uncommon, as they adopt Western ways, may be
the best available means for discovering and
assessing these factors.
Summary
A group of Indian men in Suva, Fiji, selected for their relatively high standard of
living had average systolic and diastolic blood
pressures higher than those of the sample of
the local rural Indian male population. There
is gradation in the incidence of high blood
pressure among several races of the Pacific
Islands that parallels the degree to which they
have been influenced by Western culture.
Circulation, Volume, XXIV, November 1961
STANDARD OF LIVING AND BLOOD PRESSURE
Acknowledgment
My thanks are due to Dr. Dill Russell, Director
of Medical Services Fiji, for permission to undertake
these studies and to officers of the Administration of
Fiji and the Colonial Sugar Refinery Company for
their assistance in the field work. I am grateful to
Professor R. R. H. Lovell for his valuable advice and
criticism.
References
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1. MADDOOKS, I.: The possible absence of hypertension in 2 complete Pacific Island populations. In press.
2. LOVELL, R. R. H., MADDOCKS, I., AND ROGERSON,
G. W.: The casual arterial pressure of Fijians
and Indians in Fiji. Australasian Ann. Med.
9: 4, 1960.
3. PICKERING, G. W., ROBERTS, J. A. F., AND
Sowzy, G. S. C.: The aetiology of essential
hypertension. 3. The effect of correcting for
arm circumference on the growth rate of
arterial pressure with age. Clin. Sc. 13: 267,
1954.
4. BOF, J., HUMERFELT, S., AND WEDERVANG, F.: The
blood pressure in a population. Acta med.
scandinav. Suppl. 321, 1957.
5. PADMAVATI, S., AND GUPTA, S.: Blood pressure
studies in rural and urban groups in Delhi.
Circulation 19: 395, 1959.
6. HAMILTON, M., PICKERING, G. W., ROBERTS,
J. A. F., AND SOwEY, G. S. C.: The aetiology
of essential hypertension. 1. The arterial pressure in the general population. Clin. Sc. 13:
37, 1954.
The first condition to be fulfilled by men of science, applying themselves to the investigation of natural phenomena, is to maintain absolute freedom of mind, based on philosophic doubt. Yet we must not be in the least sceptical; we must believe in science, i.e.,
in determinism; we must believe in a complete and necessary relation between things,
among the phenomena proper to living beings as well as in all others; but at the same
time we must be thoroughly convinced that we know this relation only in a more or less
approximate way, and that the theories we hold are far from embodying changeless
truths. When we propound a general theory in our sciences, we are sure only that,
literally speaking, all such theories are false. They are only partial and provisional
truths which are necessary to us, as steps on which we rest, so as to go on with investigation; they embody only the present state of our knowledge, and consequently they
must change with the growth of science, and all the more often when sciences are less
advanced in their evolution.-CLAUDE BERNARD. An Introduction to the Study of Experimental Medicine. New York, The MacMillan Company, 1927, p. 35.
Circulation, Volume XXIV, November 1961
1223
The Influence of Standard of Living on Blood Pressure in Fiji
IAN MADDOCKS
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Circulation. 1961;24:1220-1223
doi: 10.1161/01.CIR.24.5.1220
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