Non-Communicable Diseases Watch July 2018

Hypertension: A Burning Health Problem Key Messages

※ Hypertension is a major public health issue because of its high prevalence and life-threatening

complications. If left uncontrolled, the elevated blood pressure can lead to heart attack, stroke, kidney

failure, blindness and cognitive impairment etc.

※ In Hong Kong, many people have hypertension but are unaware of their condition. The Population

Health Survey 2014/15 of the Department of Health found that 27.7% of non-institutionalised persons

aged 15–84 had hypertension, including 13.2% of persons who were previously undiagnosed but

measured to have hypertension during health examination.

※ Among school children and adolescents aged 9–18 years, a local study reported that 8.2% of boys

and 2.2% of girls had hypertensive blood pressure in 2014. The corresponding proportion for

pre-hypertensive blood pressure was 18.2% for boys and 7.7% for girls.

※ In May 2018, the Hong Kong SAR Government launched “Towards 2025: Strategy and Action Plan

to Prevent and Control Non-communicable Diseases in Hong Kong” announcing a list of committed

actions with clear targets. For hypertension, the target is to contain the prevalence of raised blood

pressure by 2025. The Government will step up efforts in promoting healthy diet and physical

activity participation, adopt stronger salt reduction strategy, as well as strengthen the health system

at all levels for better management of hypertension.

※ Healthy adults should have their blood pressure checked regularly and adopt a healthy lifestyle for the

prevention and control of hypertension. Key actions include: eat a balanced diet and restrict salt intake;

be physically active and avoid prolonged sitting; maintain an optimal body weight and waist circum-

ference; do not smoke; refrain from alcohol consumption; manage stress; and take medications as

prescribed and directed by doctors.

Target 6 : Contain the prevalence of raised blood pressure

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Hypertension: A Burning Health Problem

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Non-Communicable Diseases Watch July 2018

Hypertension is persistent elevation of blood

pressure above the normal range. If left uncontrolled,

the elevated blood pressure can lead to heart

attack, stroke, kidney failure, blindness and cognitive

impairment etc.1 The higher the blood pressure,

the higher the risk of damage to the heart and blood

vessels in major organs. As hypertension rarely

shows overt symptoms in the early stages, it is a

recognised „silent killer‟. Extremely high blood

pressure may cause headache, dizziness, visual

disturbance, fatigue and facial flushing. While most

people think of hypertension as a condition that

affects older people, it has become a growing health

problem among children and adolescents.2, 3

Definition of Hypertension

Blood pressure can differ from minute to minute

with changes in posture, physical activity, emotions,

sleep or other factors. Based on the cardiovascular

morbidity and mortality association with a certain

level of blood pressure, the definition of hyperten-

sion for adults is generally defined as consistently

having systolic blood pressure equal to or above 140

millimeters of mercury (mmHg) and/or diastolic

blood pressure equal to or above 90 mmHg.1 Systolic

blood pressure between 120 mmHg and 139 mmHg

or diastolic blood pressure between 80 mmHg and

89 mmHg should also be of concern as it is a

warning sign, indicating that some lifestyle changes

are required.

For children and adolescents, diagnostic criteria for

elevated blood pressure are grounded on the concept

that blood pressure in children increases with age and

body size. It is thus impossible to utilise a single

blood pressure level to define hypertension, as done

in adults. Based on the normal distribution of blood

pressure in healthy children, pediatric hypertension is

generally defined as blood pressure in the 95th per-

centile or greater for gender, age and height on

repeated measurements. If systolic or diastolic blood

pressure is equal to or above the 90th percentile but

below the 95th percentile, or equal to or above 120/80

mmHg (whichever is lower), caution should be

raised as healthy children should not have such a

chronic health condition.4, 5

Prevalence and Causes of Hypertension

Hypertension is a major public health issue

because of its high prevalence and life-threatening

complications. Globally, more than one in five (22%)

adults have hypertension.6 In children and adoles-

cents, the prevalence of hypertension is around

3–5%. Owing to the well-established childhood

obesity epidemic and the strong relationship of blood

pressure with body weight, the prevalence of hyper-

tension in the young is increasing.2, 4, 5 Moreover,

hypertension is one of the leading risk factors for

global mortality. The Global Burden of Disease

Study 2016 reported that the number of deaths

attributed to hypertension increased from about 9.1

million in 2006 to 10.5 million in 2016, representing

a 15.1% increase in 10 years.7

Many factors contribute to the development of

hypertension and its complications. As shown in Box

1, social determinants of health can have an adverse

impact on behaviours and then provoke the develop-

ment of hypertension and related complications.1

For most children, overweight and obesity is consid-

ered the primary risk for hypertension. Compared

with children of healthy weight, obese children

would have two-fold increased risk of developing

hypertension.8 While maternal smoking during

pregnancy is an additional risk factor for hyperten-

sion in children, children who were breastfed would

have a reduced risk of hypertension.3 In fact, many

lifestyle-related risk factors of hypertension or socio-

environmental determinants are modifiable through

adoption of healthy lifestyle and sound public health

policies.1

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Non-Communicable Diseases Watch July 2018

Box 1: Main modifiable risk factors that contribute to the development of hypertension and its

complications

(Source: World Health Organization 2013)

Situation in Hong Kong

Many people in Hong Kong have hypertension

but are unaware of their condition. The Population

Health Survey 2014/15 of the Department of Health

collected data of both diagnosed and undiagnosed

cases of hypertension through self-reporting of exist-

ing diagnosis and measurement of blood pressure

respectively. The survey found that 14.6% of non-

institutionalised persons aged 15–84 self-reported

having doctor-diagnosed hypertension and another

13.2% were previously undiagnosed but measured

to have hypertension during health examination

(with systolic blood pressure equal to or above 140

mmHg and/or diastolic blood pressure equal to

or above 90 mmHg), giving an overall prevalence

of hypertension of 27.7%. As shown in Table 1, both

the prevalences of „self-reported doctor-diagnosed‟

and „previously undiagnosed but measured‟ hyperten-

sion were higher among males than females and

increased steadily with age.9

A local study examined the secular trends in blood

pressure of over 402 000 school children and adoles-

cents aged 9–18 years from 1999 to 2014. Results

showed that 8.2% of boys and 2.2% of girls had

hypertensive blood pressure (defined as systolic or

diastolic blood pressure equal to or above the 95th

percentile) in 2014. The corresponding proportion for

pre-hypertensive blood pressure (defined as systolic

or diastolic blood pressure equal to or above the 90th

percentile but below the 95th percentile or equal to

or above 120/80 mmHg) was 18.2% for boys and

7.7% for girls. From 1999 to 2014, the overall

proportion with hypertensive blood pressure and

pre-hypertensive blood pressure decreased from

30.6% to 26.4% in boys and 18.3% to 9.9% in girls

(Table 2).10

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Non-Communicable Diseases Watch July 2018

Table 1: Prevalence of hypertension among non-institutionalised persons aged 15–84 by gender and

age group

Self-reported

doctor-diagnosed hypertension

Previously undiagnosed

but measured hypertension

Total

Gender

Male 15.2% 14.9% 30.1%

Female 14.0% 11.5% 25.5%

Age group

15–24 1.0% 3.4% 4.5%

25–34 0.4% 5.2% 5.6%

35–44 3.9% 11.3% 15.2%

45–54 10.5% 16.2% 26.7%

55–64 27.0% 19.4% 46.4%

65–84 43.8% 20.9% 64.8%

Base: All respondents aged 15-84 who had participated in the health examination.

Source: Population Health Survey 2014/15, Department of Health.

Table 2: Proportion of hypertensive blood pressure and pre-hypertensive blood pressure among school

children aged 9–18 from 1999 to 2014

Year

Boys Girls

Hypertensive blood

pressure

Pre-hypertensive

blood pressure

Hypertensive blood

pressure

Pre-hypertensive

blood pressure

1999 8.7% 21.9% 5.9% 12.4%

2000 12.1% 17.7% 5.5% 10.4%

2001 12.9% 16.6% 5.2% 9.3%

2002 12.8% 16.2% 4.5% 9.7%

2003 11.0% 15.3% 3.7% 8.5%

2004 8.0% 15.9% 2.9% 7.0%

2005 6.4% 16.4% 1.7% 6.7%

2006 6.4% 17.5% 1.3% 7.0%

2007 7.5% 18.2% 1.9% 7.8%

2008 7.7% 18.0% 1.8% 7.4%

2009 8.4% 17.1% 2.1% 8.1%

2010 7.9% 16.7% 2.5% 8.2%

2011 9.1% 20.5% 2.4% 8.1%

2012 9.2% 21.5% 2.1% 8.1%

2013 8.8% 21.1% 2.3% 7.8%

2014 8.2% 18.2% 2.2% 7.7%

Source: Kwok et al 2017.

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Non-Communicable Diseases Watch July 2018

Contain the Prevalence of Raised Blood Pressure

Significant room exists for improvement in reducing

the prevalence of hypertension for Hong Kong.

In May 2018, the Government launched “Towards

2025: Strategy and Action Plan to Prevent and

Control Non-communicable Diseases in Hong

Kong” (SAP) announcing a list of committed actions

and clear targets. Of the 9 local NCD targets to be

achieved by 2025, Target 6 is to contain the

prevalence of raised blood pressure (Box 2).

To achieve such target, the Government will step

up efforts in promoting healthy diet and physical

activity participation, adopt stronger salt reduction

strategy, as well as strengthen the health system

at all levels for better management of hyperten-

sion.11

Box 2: 9 local NCD targets by 2025

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Non-Communicable Diseases Watch July 2018

Having regular blood pressure checks allows early detection of

hypertension. Healthy adults aged 18 or above in general should

have their blood pressure checked at least once every two years.

However, more frequent intervals may be required according to

the blood pressure level, individual‟s age, overall cardiovascular

risk profile, and doctor‟s advice.12 Other than having regular

blood pressure checks, adoption of healthy lifestyle is effective

for the prevention and control of hypertension. Key actions

include—

Restrict salt intake and eat a balanced diet;

Be physically active and avoid prolonged sitting;

Maintain an optimal body weight and waist circumference;

Do not smoke;

Refrain from alcohol drinking;

Manage stress; and

Take medication to control blood pressure or/and other

chronic diseases as prescribed and directed by doctors.

For more information about the Government key initiatives and

specific actions to contain the local prevalence of hypertension,

please refer to the SAP which can be found at the Change for

Health Website of DH https://www.change4health.gov.hk/en/

saptowards2025/.

References

1. A Global Brief on Hypertension. Geneva:

World Health Organization, 2013.

2. Falkner B. Hypertension in children and ado-

lescents: epidemiology and natural history.

Pediatr Nephrol 2010; 25(7):1219-24.

3. Riley M, Bluhm B. High blood pressure in

children and adolescents. Am Fam Physician

2012; 85(7):693-700.

4. Flynn JT, Kaelber DC, Baker-Smith CM, et

al. Clinical Practice Guideline for Screening

and Management of High Blood Pressure in

Children and Adolescents. Pediatrics 2017;

140(3):e20171904.

5. Lurbe E, Agabiti-Rosei E, Cruickshank JK,

et al. 2016 European Society of Hyperten-

sion guidelines for the management of high

blood pressure in children and adolescents. J

Hypertens 2016; 34(10):1887-920.

6. Global Status Report on Noncommunicble

Diseases 2014. Geneva: World Health Or-

ganization.

7. Global, regional, and national comparative

risk assessment of 84 behavioural, environ-

mental and occupational, and metabolic risks

or clusters of risks, 1990-2016: a systematic

analysis for the Global Burden of Disease

Study 2016. Lancet 2017; 390(10100):1345-

1422.

8. Parker ED, Sinaiko AR, Kharbanda EO, et

al. Change in Weight Status and Develop-

ment of Hypertension. Pediatrics 2016; 137

(3):e20151662.

9. Population Health Survey 2014/15. Hong

Kong SAR: Department of Health. 10. Kwok MK, Leung GM, Chung TWH, et al.

Divergent secular trends in blood pressure

and body mass index in children and adoles-

cents in Hong Kong. Sci Rep 2017; 7

(1):4763.

11. Towards 2025: Strategy andAction Plan to

Prevent and Control Non-communicable

Diseases in Hong Kong. Hong Kong SAR:

Food and Health Bureau, May 2018.

12. Hong Kong Reference Framework for Hy-

pertension Care for Adults in Primary Care

Settings (Patient Version). Hong Kong SAR:

Task Force on Conceptual Model and Pre-

ventive Protocols of the Working Group on

Primary Care; Revised in 2018.

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Non-Communicable Diseases Watch July 2018

The Leisure and Cultural Services Department (LCSD) will hold Sport For All Day 2018

on August 5 (Sunday) to encourage people of all ages and those with disabilities to maintain

a healthy lifestyle by participating more in various sports activities and to form the habit of

exercising at least half an hour a day.

“Stay Active, Healthy and Happy!” has been adopted as the slogan. Clear and catchy, the slogan

is tailored to remind everybody of the benefits of daily exercise on both the body and the mind,

and encourage members of the public to include exercise in their everyday routine.

On the day of the event, various recreation and sports programmes will be offered at designated

venues in the 18 districts, and most of the leisure facilities of the LCSD will be open for public use,

all free of charge. For details of the free programmes and facilities for free use, please visit the

Sport For All Day designated website: http://www.lcsd.gov.hk/en/sfad/2018/index.html.

Non-Communicable Diseases (NCD) WATCH is dedicated to

promote public’s awareness of and disseminate health information

about non-communicable diseases and related issues, and the

importance of their prevention and control. It is also an indication of

our commitments in responsive risk communication and to address

the growing non-communicable disease threats to the health of our

community. The Editorial Board welcomes your views and comments.

Please send all comments and/or questions to so_dp3@dh.gov.hk.

Editor-in-Chief

Dr Regina CHING

Members

Dr Thomas CHUNG Dr Ruby LEE

Dr Cecilia FAN Mr YH LEE

Dr Anne FUNG Dr Eddy NG

Dr Rita HO Dr Lilian WAN

Dr Karen LEE Dr Karine WONG