mortality or risk factors in as much as the control group was 7. WHO ( 1 9 8 5 ) . Techn. Rep. Ser. No 726.
not properly chosen. 8. Hetzel, B.S. (1979). In : Measurement of Levels of Health, WHO.
4. Oslow diet/smoking Intervention Study (42). 9. Rose, G. ( 1 9 8 5 ) I n : Oxford Textbook of Public Health, Vol. 4, p. 133.
10. Hart, J.T. (1983) In : Practising Prevention, British Medical
This study began in 1 9 7 3 . 1 6 , 2 0 2 Norwegian men aged Association.
40-49 years were screened for coronary risk factors; of these 11. Stamler, J. ( 1 9 8 5 ) . N. Eng. J. Med., 3 1 2 : 1053.
1232 healthy normotensive men at high risk (total serum 12. WHO ( 1 9 8 3 ) . Bull WHO, 6 1 : 45.
cholesterol 290-379 mg/di; s m o k i n g ) of CHO were selected 13. WHO ( 1 9 8 5 ) Primary Prevention of CHO EURO Rep and Studies 98.
for a 5 year randomized trial. The aim of the study was to Copenhagen.
determine whether lowering of serum lipids and cessation of 14. WHO ( 2 0 1 1 ) , Disease and injury, Regional estimates, cause specific
estimates for 2008.
smoking would reduce the incidence of first attack of CHO in
15. ICMR (2004), Assessment of Burden of Non-Communicable Diseases,
males aged 40-50.
The intervention group underwent techniques designed 16. Govt. of India ( 2 0 1 1 ), National Health Profile 2 0 1 1 , Ministry of Health
to lower serum cholesterol level through dietary means ( e . g . , and Family Welfare, New Delhi.
a polyunsaturated fat diet), and to decrease or eliminate 17. Slone, D. et al ( 1 9 7 8 ) . N. Eng. J. Med. 2 9 8 : 1 273 .
smoking. At the end of 5 years, the incidence of myocardial 18. Shaper A . G . et al ( 1 9 8 1 ) . Brit. Med. J. 2 8 3 : 1 7 9 .
infarction (fatal and nonfatal) was lower by 4 7 per cent in 19. WHO ( 1 9 7 9 ) . Tech. Rep. Ser., No. 636.
20. WHO ( 1 9 9 6 ) , Tech. Rep. Ser. No. 862, Hypertension control.
the intervention group than in the control group.
21. Bain, C. e t a l ( 1 9 7 8 ) . Lancet, 1 : 1087.
With this study, primary prevention of CHO entered the
22. Wald, N.J. ( 1 9 7 6 ) . Lancet, 1 : 1 3 6 .
practical field of preventive medicine in an impressive
23. Kannel, W.B. ( 1 9 7 6 ) . A m . J. Cardiol., 3 7 : 269.
24. Keys, A. ( 1 9 8 0 ) . Seven Countries: a multivariate analysis of death and
CHO, Harvard University Press, Cambridge, M.A.
5 . Lipid Research C l i n i c s Study (43)
25. Gordon, T. et al ( 1 9 7 7 ) . Am. J. Med., 6 2 : 707.
This double-blind, randomized clinical trial involved 26. Superko, H . R . et al ( 1 9 8 5 ) . Am. J. Med., 7 8 : 826.
3806 asymptomatic “high-risk” American men aged 35-59 27. Schaefer, E.J. ( 1 9 8 5 ) . N. Eng. J. Med., 3 1 2 : 1300.
years with typeII hyperlipoproteinaemia. The trial was 28. WHO ( 1 9 8 5 ) . Techn. Rep. Ser., 7 2 7 .
29. Miller,N.E.eta1(1979)Lancet, 1 : 1 1 1 .
designed to test whether reducing serum cholesterol would
30. Phillips, G . B . ( 1 9 8 5 ) . A m . J. Med., 78 (3) 363.
prevent CHO events.
31. Jenkins, C . D . et al ( 1 9 7 4 ) . N. Eng. J. Med., 290: 1271.
The men were randomized into two groups, one receiving
32. WHO ( 1 9 8 6 ) Techn. Rep. Ser., No. 732.
cholestyramine and the other receiving a placebo. Both the
33. Mann, J . I . et al ( 1 9 7 6 ) . Brit. Med. J., 2 : 445.
groups were followed for an average of 7.4 years.
34. WHO (2008), The Global Burden of disease, 2004 update.
The treatment group had an 8.5 per cent and 1 2 . 6 per 35. WHO ( 1 9 8 6 ) . Techn. Rep. Ser., No. 732.
cent greater reduction in total cholesterol and LDL 36. Rose, G . ( 1 9 8 1 ) . Brit. Med. J., 2 8 2 : 1847.
cholesterol levels respectively than the placebo-treated 37. Puska, P. e t a l ( 1 9 7 9 ) . Brit. Med. J., 2 : 1 1 7 3 .
38. Multiple risk factor Intervention Trial Research Group ( 1 9 8 2 ) . JAMA,
group. This difference resulted in a 24 per cent reduction in
2 4 8 : 1465.
death from definite CHO and a 19 per cent reduction in
39. Farquhar,J.etal(1977).Lancet., 1 : 1192.
non-fatal myocardial infarction. The findings of this study
40. Salonen, J.T. et al ( 1 9 8 3 ) . Brit. Med. J., 2 8 6 : 1857.
have resulted in enthusiasm for the drug treatment of those
41. Lancet ( 1 9 8 5 ) . 1 : 320.
men with considerably elevated serum cholesterol levels.
42. Hjermann. I. et al ( 1 9 8 1 ) . Lancet, 2 : 1 30 3.
43. Lipid Research Clinics Programme ( 1 9 8 4 ) . JAMA, 2 5 1 : 3 5 1 .
Secondary prevention trials
44. Glasunov, I. et al ( 1 9 7 3 ) . Int. J. Ept., 2 (2) 1 3 7 .
Secondary prevention trials are aimed at preventing a 45. Bradely, N . ( 1 9 8 4 ) . I n : Medical Annual, D . J . P. Gray (ed ). John Wright
subsequent coronary attack or sudden death. A wide range and Sons.
of clinical trials have been performed with four main groups 46. Rose, G. ( 1 9 7 5 ) . Brit. J. PSM, 2 9 : 147.
47. G. Lamm ( 1 9 7 9 ) I n : Measurement of Levels of Health, WHO Reg.
of drugs – anti-coagulants, lipid-lowering agents (e.g.,
Publ. EURO Ser. No. 7 .
clofibrate), anti-thrombotic agents (e.g., aspirin) and beta
48. Lawrence M. Tierney, Jr. Stephen J. Mcphee Maxine A. Papadakis,
blockers. The most promising results to date have come from
Current Medical Diagnosis and Treatment, 41st Ed., 2002, Large
beta blockers. Publication.
In general the above studies and similar others show that 49. Dawber, T.R. (1980). The Framingham Study, Cambridege, M.A.,
Harvard University Press.
it is feasible through well-planned intervention programmes
50. Kannel, W.B. et al ( 1 9 7 6 ) . Am. J. Cardiol., 3 8 : 46.
to reduce the risk factors in the populations studied. The
primary and secondary prevention studies promise at
present to be the main contribution of epidemiology to the .HYPERTENSION
conquest of chronic diseases.
Hypertension is a chronic condition of concern due to its
References role in the causation of coronary heart disease, stroke and
1. WHO ( 1 9 8 2 ) . Techn Rep. Ser. No. 678. other vascular complications. It is the commonest
2. Pedoe, H.T. (1982). In Epidemiology of Diseases, D.L. Miller and cardiovascular disorder, posing a major public . health
R.T.D. Farmer ( e d s ) , Blackkwell, Oxford. challenge to population in socio-economic and
3. Rose, G.A. ( 1 9 7 3 ) . I n : Chronic Diseases, Public Health in Europe No.
epidemiological transition. It is one of the major risk factors
2, Regional Office of WHO, Copenhagen.
for cardiovascular mortality, which accounts for 20-50 per
4. WHO ( 1 9 7 2 ) . WHO Statis Rep., 25:430.
· cent of all deaths.
5. Oliver, M.F. ( 1 9 8 1 ) . Br. Med. Bull., 37 ( 1 ) 49.
6. Rose, G.A. and Blackburn, H. (1968). Cardiovascular Survey Definition of hypertension is difficult and, by necessity
Methods, Geneva, WHO. arbitrary. Sir George Peckering first fomulated a concept
that blood pressure in a population is distributed A few salient points need be mentioned about measuring
continuously as a bell-shaped curve with no real separation blood pressure. A WHO Study Group (4) recommended the
between normotension and hypertension ( 1 ) . There is also a sitting position than the supine position for recording blood
direct relation between cardiovascular risk and blood pressure. In any clinic a uniform policy should be adopted,
pressure : the higher the blood pressure, the higher the risk using either the right or left arm consistently. The pressure at
of both stroke and coronary events ( 1 ) . As a consequence, which the sounds are first heard (phase I) is taken to indicate
the dividing line between normal and high blood pressure the systolic pressure. Near the diastolic pressure the sounds first
can be defined only in an operational way. become muffled (phase IV) and then disappear (phase V).
As intervention trials included only adults aged 1 8 years Most of the studies have used phase V to measure diastolic
or older, definition and classification of hypertension refer to blood pressure. The systolic and diastolic pressures should be
adults not taking anti-hypertensive drugs and not actually ill, measured at least three times over a period of at least 3 minutes
and based on the average of two or more readings on two or and the lowest reading recorded. For reasons of comparability,
more occasions after initial screening. Table 1 shows the the data should be recorded everywhere in a uniform way.
classification of hypertension by blood pressure level.
TABLE 1 Hypertension is divided into primary (essential) and
Classification of blood pressure measurements secondary. Hypertension is classified as “essential” when the
causes are generally unknown. Essential hypertension is the
most prevalent form of hypertension accounting for 90 per
cent of all cases of hypertension. Hypertension is classified
as “secondary” when some other disease process or
abnormality is involved in its causation. Prominent among
Normal < 120 < 80
these are diseases of kidney (chronic glomerulo-nephritis
Pre-hypertension 120-139 or 80-90
and chronic pyelonephritis}, tumours of the adrenal glands,
congenital narrowing of the aorta and toxemias of
· Stage.L 140-159 or 90-99 pregnancy. Altogether, these are estimated to account for
Stage 2 �160 oi �100 about 1 0 per cent or less of the cases of hypertension.
Source : (2) Magnitude of the problem
Although blood pressure is easily measured, it had taken
When systolic and diastolic: blood pressure fall into
several decades to realise that arterial hypertension is a
different categories, the higher category should be selected
frequent, worldwide health disorder (5).
to classify the individual’s blood pressure. “Isolated systolic
hypertension” is defined as a systolic blood pressure of
“Rule of halves”
140 mm of Hg or more and a diastolic blood pressure of less
than 90 mm of Hg. Hypertension is an “iceberg” disease. It became evident
in the early 1 9 7 0 s that only about half of the hypertensive
Organ damage subjects in the general population of most developed
countries were aware of the condition, only about half of
Although the extent of organ damage often correlates
those aware of the problem were being treated, and only
with the level of blood pressure, it is not always the case. In
about half of those treated were considered adequately
addition the rate of progression of organ damage varies
treated (6). Fig. 1 illustrates this situation (7). If this was the
from one individual to another depending on many
situation in countries with highly developed medical
influences, most of which are incompletely understood.
services, in the developing countries, the proportion treated
Therefore, blood pressure and organ impairment should be
would be far too less.
evaluated separately, since markedly high pressures may be
seen without organ damage and, conversely, organ damage
may be present with only moderate elevation. of blood
pressure. The presence of signs of organ damage confers an
increased cardiovascular risk to any level of blood pressure.
Blood pressure measurement
Despite more than 75 years of experience with the
measurement of blood pressure, discussion continues about
its reliability and wide variability in individual subjects.
Accurate measurements are essential under standardized
conditions for valid comparison between persons or groups
over time. Three sources of errors have been identified in
the recording of blood pressure : (a) Observer errors : e . g . ,
hearing acuity, interpretation of Korotkow sounds.
(b) Instrumental errors : e . g . , leaking valve, cuffs that do not
encircle the arm. If the cuff is too small and fails to encircle
the arm properly then too high a reading will be obtained; Hypertension in the community
and (c) Subject errors : e.g., the circumstances of
examination. These include the physical environment, the The areas of the circles shown in Fig. 1 correspond to the
position of the subject, external stimuli such as fear, anxiety, actual proportions observed in several population based
and so on (3). studies and number-wise represent the following : (6).
1. The whole community individuals grow older. This phenomenon of persistence of
2. Normotensive subjects rank order of blood pressure has been described as
“tracking” (11). This knowledge can be applied in
3. Hypertensive subjects
identifying children and adolescents “at risk” of developing
4. Undiagnosed hypertension
hypertension at a future date.
5. Diagnosed hypertension
6. Diagnosed but untreated
7. Diagnosed and treated �
8. Inadequately treated “‘
9. Adequately treated 0.
INCIDENCE : The concept of incidence has limited value 0
in hypertension because of the variability of consecutive
readings in individuals, ambiguity of what is “normal” blood
pressure and the insidious nature of the condition (8).
Worldwide, raised blood pressure is estimated to cause
7 .5 million deaths, about 1 2 . 8 per cent of the total of all
annual deaths. This accounts for 57 million DALYs or
3. 7 per cent of total DALYs. It is a major risk factor for
coronary heart disease and ischaemic as well as
haemorrhagic stroke. In some age groups, the risk of
cardiovascular disease doubles for each incremental increase
Tracking of blood pressure
of 20/10 mm Hg of blood pressure. In addition, complication
of raised blood pressure includes heart failure, peripheral Risk factors for hypertension
vascular disease, renal impairment, retinal haemorrhage and
Hypertension is not only one of the major risk factors for
visual impairment. Treating systolic and diastolic blood
most forms of cardiovascular disease, but that it is a
pressure so that they are below 140/90 mm Hg is associated
condition with its own risk factors. A WHO Scientific Group
with a reduction in cardiovascular complications (9).
(5) has recently reviewed the risk. factors for essential
Globally, the overall prevalence of raised blood pressure hypertension. These may be classified as :
in adults aged 25 years and over was around 40 per cent in
1 . Non-modifiable risk factors
2008 (9). The proportion of the world’s population with high
blood pressure, or uncontrolled hypertension, fell modestly (a) AGE : Blood pressure rises with age in both sexes and
between 1980 and 2008. However, because of population the rise is greater in those with higher initial blood pressure.
growth and ageing, the number of people with hypertension Age probably represents an accumulation of environmental
rose from 600 million in 1980 to 1 billion in 2008 (9). influences and the effects of genetically programmed
senescence in body systems (3). Some populations have
Across the income groups of countries, the prevalence of
now been identified whose mean blood pressure does not
raised blood pressure was consistently high, with low, lower
rise with age (12). These communities are for the most part
middle and upper-middle-income countries all having rates
primitive societies with calorie and often salt intakes at
of around 40% for both sexes. The prevalence in high
income countries was lower, at 35% for both sexes.
(b) S E X : Early in life there is little evidence of a difference
Prevalence in I n d i a in blood pressure between the sexes. However, at
adolescence, men display a higher average level. This
A community based survey was carried out by ICMR
difference is most evident in young and middle aged adults.
during 2007-08 to identify the risk factors for non
Late in life the difference narrows and the pattern may even
communicable diseases under state based Integrated Disease
be reversed ( 1 ) . Post-menopausalchanges in women may be
Surveillance Project Phase I. The survey was carried out in
the contributory factor for this change. Studies are in progress
the states of Andhra Pradesh, Kerala, Madhya Pradesh,
to evaluate whether oestrogen supplementation protects
Maharashtra, Uttarakhand, Tamil Nadu and Mizoram.
against the late relative rise of blood pressure in women ( 1 ) .
According to the survey report, the prevalence of
(c) GENETIC FACTORS: There is considerable evidence
hypertension was varying from 1 7 to 2 1 per cent in all the
that blood pressure levels are determined in part by genetic
states with marginal rural-urban differences. Overall pattern
factors, and that the inheritance is polygenic. The evidence
of prevalence was found increasing with age groups in all
is based on twin and family studies. Twin studies have
states. Though hypertension was prevalent in all educational
confirmed the importance of genetic factors in hypertension.
levels, it was high in higher education levels of Uttarakhand,
The blood pressure values of monozygotic twins are usually
Mizoram and Madhya Pradesh. Hypertension was
more strongly correlated than those of zygotic twins. In
comparatively more prevalent in executive and service
contrast, no significant correlation has been noted between
categories in all the states ( 1 0 ) .
husbands and wives, and between adopted children and
“Tracking” of b l o o d pressure their adoptive parents (5).
If blood pressure levels of individuals were followed up Family studies have shown that the children of two
over a period of years from early childhood into adult life, normotensive parents have 3 per cent possibility of
then those individuals whose pressures were initially high in developing hypertension, whereas this possibility is 45 per
the distribution, would probably continue in the same cent in children of two hypertensive parents (13). Blood
“track” as adults. In other words, low blood pressure levels pressure levels among first degree adult relatives have also
tend to remain low, and high levels tend to become higher as been noted to be statistically significant (5).
Attempts to find genetic markers that are associated with (g) PHYSICAL ACTIVITY: Physical activity by reducing
hypertension have been largely unsuccessful. The detailed body weight may have an indirect effect on blood pressure.
mechanism of heredity, i.e., how many genes and loci are
(h) ENVIRONMENTAL STRESS : The term hypertension
involved and their mode of inheritance have not yet been
itself implies a disorder initiated by tension or stress. Since
conclusively elucidated. stress is nowhere defined, the hypothesis is untestable (3).
(d) ETHNICITY : Population studies have consistently However, it is an accepted fact that psychosocial factors
revealed higher blood pressure levels in black communities operate through mental processes, consciously or
than other ethnic groups (1). Average difference in blood unconsciously, to produce hypertension. Virtually all studies
pressure between the two groups vary from slightly less than on blood pressure and catecholamine levels in young people
5 mm Hg during the second decade of life to nearly 20 mm revealed significantly higher noradrenaline levels in
Hg during the sixth. Black Americans of African origin have hypertensives than in normotensives. This supports the
contention that over-activity of the sympathetic nervous
been demonstrated to have higher blood pressure levels
system has an important part to play in the pathogenesis of
hypertension ( 1 1 ) .
2 . Modifiable risk f a c t o r s . (i) SOCIO-ECONOMIC STATUS : In countries that are in
post-transitional stage of economic and epidemiological
(a) OBESITY : Epidemiological observations have
change, consistently higher levels of blood pressure have
identified obesity as a risk factor for hypertension ( 1 4 ) . The
been noted in lower socio-economic groups. This inverse
greater the weight gain, the greater the risk of high blood
relation has been noted with levels of education, income
pressure. Data also indicate that when people with high
and occupation. However, in societies that are transitional
blood pressure lose weight, their blood pressure generally
or pre-transitional, a higher prevalence of hypertension
decreases. “Central obesity” indicated by an increased waist
have been noted in upper socio-economic groups.
to hip ratio, has been positively correlated with high blood
This probably represents the initial stage of the epidemic of
pressure in several populations.
CVD ( 1 ) .
(b) SALT INTAKE : There is an increasing body of
(j) OTHER FACTORS : The commonest present cause of
evidence to the effect that a high salt intake ( i . e . , 7-8 g per
secondary hypertension is oral contraception, because of
day) increases blood pressure proportionately. Low sodium
the oestrogen component in combined preparations. Other
intake has been found to lower the blood pressure ( 1 5 ) . For
factors such as noise, vibration, temperature and humidity
instance, the higher incidence of hypertension is found in
require further investigation (5).
Japan where sodium intake is above 400 mmol/day while
primitive societies ingesting less than 60 mmol/day have
virtually no hypertension (16). It has been postulated that PREVENTION OF HYPERTENSION
essential hypertensives have a genetic abnormality of the
kidney which makes salt excretion difficult except at raised The low prevalence of hypertension in some communities
levels of arterial pressure (5). indicates that hypertension is potentially preventable ( 1 8 ) .
The WHO has recommended the following approaches in
Besides sodium, there are other mineral elements such as
the prevention of hypertension :
potassium which are determinants of blood pressure.
Potassium antagonizes the biological effects of sodium, and 1. Primary prevention
thereby reduces blood pressure. Potassium supplements (a) Population strategy
have been found to lower blood pressure of mild to
(b) High-risk strategy
moderate hypertensives. Other cations such as calcium,
2. Secondary prevention
cadmium and magnesium have also been suggested as of
importance in reducing blood pressure levels.
1 . PRIMARY PREVENTION
(c) SATURATED FAT : The evidences suggest that
Although control of hypertension can be successfully
saturated fat raises blood pressure as well as serum
achieved by medication (secondary prevention) the ultimate
cholesterol ( 1 7 ) . For further details refer to chapter 1 0 .
goal in general is primary prevention. Primary prevention
(d) DIETARY FIBRE : Several studies indicate that the
has been defined as “all measures to reduce the incidence of
risk of CHD and hypertension is inversely related to the disease in a population by reducing the risk of onset” (19).
consumption of dietary fibre. Most fibres reduce plasma total The earlier the prevention starts the more likely it is to be
and LDL cholesterol ( 1 ) . effective.
(e) A L C O H O L : High alcohol intake is associated with an In connection with primary prevention, terms such as
increased risk of high blood pressure. It appears that alcohol “population strategy” and “high-risk strategy” have become
consumption raises systolic pressure more than the diastolic. established (5, 20). The WHO has recommended these
But the finding that blood pressure returns to normal with approaches in the prevention of hypertension. Both the
abstinence suggests that alcohol-induced elevations may approaches are complementary.
not be fixed, and do not necessarily lead to sustained blood
pressure elevation (3). a. POPULATION STRATEGY
(f) HEART RATE : When groups of normotensive and The population approach is directed at the whole
untreated hypertensive subjects, matched for age and sex, population, irrespective of individual risk levels. The
are compared, the heart rate of the hypertensive group is concept of population approach is based on the fact that
invariably higher. This may reflect a resetting of sympathetic even a small reduction in the average blood pressure of a
activity at a higher level. The role of heart variability in population would produce a large reduction in the incidence
blood pressure needs further research to elucidate whether of cardiovascular complications such as stroke and
the relation is casual or prognostic ( 1 ) . CHD (18). The goal of the population approach is to shift
the community distribution of blood pressure towards lower Detection of high-risk subjects should be encouraged by
levels or “biological normality” (11). This involves a the optimum use of clinical methods. Since hypertension
multifactorial approach, based on the following tends to cluster in families, the family history of
non-pharmacotherapeutic interventions : hypertension and “tracking” of blood pressure from
childhood may be used to identify individuals at risk.
(a) NUTRITION : Dietary changes are of paramount
importance. These comprise : ( i ) reduction of salt intake to
2 . SECONDARY PREVENTION
an average of not more than 5 g per day (ii) moderate fat
intake (iii) the avoidance of a high alcohol intake, and The goal of secondary prevention is to detect and control
(iv) restriction of energy intake appropriate to body needs. high blood pressure in affected individuals. Modern anti
(b) WEIGHT REDUCTION : The prevention and correction hypertensive drug therapy can effectively reduce high blood
of over weight/obesity (Body Mass Index greater than 25) is pressure and consequently, the excess risk of morbidity and
a prudent way of reducing the risk of hypertension and mortality from coronary, cerebrovascular and kidney
indirectly CHO; it goes with dietary changes. (c) EXERCISE disease. The control measures comprise:
PROMOTION : The evidence that regular physical activity (i) EARLY CASE DETECTION : Early detection is a major
leads to a fall in body weight, blood lipids and blood problem. This is because high blood pressure rarely causes
pressure goes to suggest that regular physical activity should symptoms until organic damage has already occurred, and
be encouraged as part of the strategy for risk-factor control our aim should be to control it before this happens. The only
(25). (d) BEHAVIOURAL CHANGES : Reduction of stress effective method of diagnosis of hypertension is to screen the
and smoking, modification of personal life-style, yoga and population. But screening, that is not linked to follow-up and
transcendental meditation could be profitable. (e) HEALTH sustained care, is a fruitless exercise. It is emphasized that
EDUCATION : The general public require preventive advice screening should not be initiated if health resources for
on all risk factors and related health behaviour. The whole treatment and follow-up are not adequate.
community must be mobilized and made aware of the
In the developed countries, mass screening is not
possibility of primary prevention, and (f) SELF-CARE : An
considered essential for the adequate control of blood
important element in community-based health programmes
pressure in the population. In Europe, the large majority of
is patient participation. The patient is taught self-care, i.e.,
people have at least one contact in every 2 years with the
to take his own blood pressure and keep a log-book of his
health service. If blood pressure is measured at each such
readings. By doing so, the burden on the official health
contact, the bulk of the problem of detecting those in need
services would be considerably reduced. Log-books can
of intervention is solved.
also be useful for statistical purposes and for the long-term
(ii) TREATMENT : In essential hypertension, as in
follow-up of cases (22).
diabetes, we cannot treat the cause, because we do not
Table 2 shows some of the lifestyle modifications to
know what it is. Instead, we try to scale down the high blood
pressure to acceptable levels. The aim of treatment should
be to obtain a blood pressure below 140/90, and ideally a
b. HIGH-RISK STRATEGY
blood pressure of 120/80. Control of hypertension has been
This is also part of primary prevention. The aim of this shown to reduce the incidence of stroke and other
approach is “to prevent the attainment of levels of blood complications. This. is a major reason for identifying and
pressure at which the institution of treatment would be treating asymptomatic hypertension. Care of hypertensives
considered” (3). This approach is appropriate if the risk should also involve attention to other risk factors such as
factors occur with very low prevalence in the community (3). smoking and elevated blood cholesterol levels ( 1 8 ) .
Lifestyle modifications to manage hypertension
Weight reduction Maintain normal body weight (BM!, 18.5-24.9) 5-20 mm Hg/10 kg
weight loss ·
Adopt DASH Consume a diet rich in fruits, vegetables and low-fat dairy products with a 8-14mmHg
eating plan reduced content of saturated fat and total fat
Dietary sodium R�duce dietary sodium intake to no more than 100 �Eq/d 2 – 8 m m Hg
reduction (2.4 g sodium or 6 g sodium chloride}
Physical activity Engage in regular aerobic physical activity such as brisk walking . 4 ,- 9 m m Hg
(at least 30 minutes per day, most days of the week)
Moderation of alcohol Limit consumption to no more than two drinks per day 2-4 min Hg
consumption ( 1 oz or 30 ml ethanol eg, 24 oz beer, 10 oz wine, or 3 oz 80- proof whisky}
in most men, and no more than one drink per day in women and
lighter-wetght persons .
For overall cardiovascular risk reduction, stop smoking.
The effects of implementing these modifications are dose and time dependent and could be higher for some individuals.
BM! – body mass index calculated as weight in kilograms divided by the square of height in metres;
DASH – Dietary Approaches to Stop Hypertension.
S o u r c e : (2)
_ E__ ..• 37,7
(iii) PATIENT COMPLIANCE : The treatment of high deficit”) manifests itself by various neurological signs and
blood pressure must normally be life-long and this presents symptoms that are related to extent and site of the area
problems of patient compliance, which is defined as “the involved and to the underlying causes. These include coma,
extent to which patient behaviour (in terms of taking hemiplegia, paraplegia, monoplegia, multiple paralysis,
medicines, following diets or executing other lifestyle speech disturbances, nerve paresis, sensory impairment, etc.
changes) coincides with clinical prescription”. The Of these hemiplegia constitutes the main somatoneurological
compliance rates can be improved through education disorder in about 90 per cent of patients (2).
directed to patients, families and the community.
Stroke includes a number of syndromes with differing
Intensive research carried out during the past decade, aetiologies, epidemiology, prognosis and treatment. These
aiming at control of hypertension at the community level, are listed below :
has already provided valuable results. The studies have
A. Ischaemic stroke
shown that control of hypertension in a population is
a. Lacunar infarct
feasible, that it can be carried out through the existing system
b. Carotid circulation obstruction
of health services in different countries, and that the control
c. Vertebra-basilar obstruction
of blood pressure leads to a reduction of complications of
high blood pressure – namely stroke, heart failure and renal B. Haemorrhagic stroke
failure. In some of the projects the incidence of myocardial a. Spontaneous intracerebral haemorrhage
infarction was also reduced. As a result of these findings b. Subarachnoid haemorrhage
some countries have launched nationwide control c. Intracranial aneurysm
programmes in the field of hypertension (23). d. Arteriovenous malformations.
1. WHO ( 1 9 9 6 ) . Techn. Rep. Ser., No. 862.
Stroke is a worldwide health problem. It makes an
2. STEPHEN J. McPHEE, MAXINE A. PAPADAKIS (2010), Current
important contribution to morbidity, mortality and disability
Medical Diagnosis and Treatment, 49th Ed. A Lange Publication.
in developed as well as developing countries. Although there
3. Hart, J.T. (1980). Hypertension, Library of General Practitioner
are substantial differences in frequency from place to place,
Series, Churchill Livingstone.
cerebral thrombosis is usually the most frequent form of
4. WHO ( 1 9 8 3 ) . Bull WHO, 6 1 ( 1 ) 53.
stroke encountered in clinical studies, followed by
5. WHO ( 1 9 8 3 ) . Techn. Rep. Ser., No. 686.
6. Strasser, T. ( 1 9 7 2 ) . WHO Chronicle, 2 6 : 4 5 1 .
haemorrhage. Subarachnoid haemorrhage and cerebral
7. WHO ( 1 9 7 4 ) . WHO Chronicle, 28 (3) 1 1 . embolism come next as regards both mortality and
8. Pedoe, H.T. ( 1 9 8 2 ) . I n : Epidemiology of Diseases, D.L. Miller and morbidity (2). However, stroke from cerebral haemorrhage
R.T.D. Farmer ( e d s ) , Blackwell, Oxford. is more common in Japan than elsewhere ( 1 ) .
9. WHO ( 2 0 1 1 ) , Global Status Report on Non-communicable Diseases,
2010. MORBIDITY AND MORTALITY
10. Govt. oflndia ( 2 0 1 1 ) , National Health Report 2 0 1 1 , Ministry of Health
Cerebrovascular disease remain a leading cause of death
and Family Welfare, New Delhi.
from NCDs. In 2008 it was estimated that cerebrovascular
11. WHO ( 1 9 8 5 ) . Techn. Rep. Ser., No. 7 1 5 .
disease accounted for 6.1 million deaths worldwide,
12. Marmot, M . G . (1984). Brit. Med. Bulletin, 40 (4) 380.
equivalent to 1 0 . 8 per cent of all deaths. Majority of these
13. Bianchi, G . et al ( 1 9 7 9 ) . Lancet, 1 : 1 7 3 – 1 7 7 .
deaths occurred in people living in developing countries and
14. Stamler, R. et al ( 1 9 7 8 ) . JAMA, 2 4 0 : 1607.
15. Beard, T.C. et al ( 1 9 8 2 ) . Lancet, 2 : 455.
33. 72 per cent of the subjects were aged less than 70 years
16. Oliver, M.F. ( 1 9 8 1 ) . Br. Med. Bull., 37 ( 1 ) 49. (3). Additionally, cerebrovascular disease is the leading
17. Puska, P. et al ( 1 9 8 3 ) . Lancet, 1 : 1-5. cause of disability in adults and each year millions of stroke
18. WHO ( 1 9 8 6 ) . Techn. Rep. Ser., No. 732. survivors have to adopt life with restriction in activities of
19. Hogarth, J. (1978). Glossary Health Care Terminology, WHO, daily living as a consequence of stroke. Many surviving
Copenhagen. stroke patients will often depend on other people’s
20. Rose, G. ( 1 9 8 1 ) . Brit.Med.J., 1 : 1847. continuous support to live (4).
21. WHO ( 1 9 8 2 ) . Techn. Rep. Ser., No. 678.
In demographically developed countries, the average age
22. WHO ( 1 9 7 8 ) . WHO Chronicle, 32 ( 1 1 ) 448.
at which stroke occurs is around 73 years reflecting the older
23. WHO ( 1 9 8 0 ) . Sixth Report World Health Situation, Part I.
age structure of these countries. The probability of a first
stroke or first TIA is around 1 . 6 per 1000 and 0.42 per 1000
respectively. In less developed regions, the average age of
stroke is less due to the different population age structure,
The term “stroke” (syn : apoplexy) is applied to acute
resulting from higher mortality rates.
severe manifestations of cerebrovascular disease. It causes
both physical and mental crippling. WHO defined stroke as Stroke patients are at highest risk of death in the first
“rapidly developed clinical signs of focal disturbance of weeks after the event, and between 20-50 per cent die
cerebral function; lasting more than 24 hours or leading within first month depending on type, severity, age, co
to death, with no apparent cause other than vascular morbidity and effectiveness of treatment of complications.
origin” ( 1 ) . The 24 hours threshold in the definition excludes Patients who survive may be left with no disability or with
transcient ischaemic attacks (TIA) which is defined to last mild, moderate or severe disability. Considerable
less than 24 hours, and patients with stroke symptoms spontaneous recovery occurs upto about 6 months.
caused by subdural haemorrhage, tumours, poisoning or However, patients with history of stroke are at high risk of a
trauma are excluded. subsequent event of around 1 0 per cent in the first year and
5 per cent year thereafter (4).
The disturbance of cerebral function is caused by three
morphological abnormalities, i.e., stenosis, occlusion or The proportion of patients achieving independence in
rupture of the arteries. Dysfunction of the brain ( “neurological self-care by one year after a stroke range from around