The Epidemiology
UNIT
of Chronic
1
Diseases: An
Overview
Introduction
That you have chosen this module suggests that you recognize the burden
associated with chronic diseases. We will start this unit by describing what
chronic non communicable diseases are. We will then look at how big the
problem of chronic diseases is globally - in developed and developing countries,
highlighting its scale in sub-Saharan Africa in general and Southern Africa in
particular.
There are THREE sessions in this unit.
Study Session 1: An introduction to epidemiology and implication of chronic non
communicable diseases
Study Session 2: Demographic, epidemiological and nutrition transition
Study Session 3: Social Determinants for non communicable diseases
In session 1 we explain what chronic diseases are, and the diseases that fall into
this category. We also start to develop an overview of why they are a concern.
We also highlight the burden associated with chronic disease globally and in
developing countries, dispelling assumptions that certain parts of the world are
completely unaffected by chronic diseases. Basic concepts in chronic disease
epidemiology are also defined.
In session 2, we discuss demographic, epidemiological and nutrition transition
and how these relate to the development of chronic diseases.
In session 3, we look at how social determinants of health are associated with
non communicable diseases
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Unit 1 - Session 1
Introduction: Epidemiology
and implications of Chronic
Non Communicable Diseases
Contents
1.
2.
3.
4.
5.
6.
7.
8.
Learning outcomes of this session
Readings
Defining chronic disease
How big is the problem of chronic diseases?
Who is affected by chronic diseases?
Burdens associated with chronic diseases
The impact of chronic diseases on health services
Session summary
Timing of this session
There are four readings and seven tasks in this session. It should take you about
two hours to complete.
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LEARNING OUTCOMES OF SESSION 1
In the course of this session, you will be addressing the Session Outcomes in
the left column; they relate to the Module Outcomes indicated in the right
hand column:
Session Outcomes






2.
Explain the terms ‘chronic diseases’
and chronic non communicable
disease
Describe the extent of the problem.
Explain why chronic diseases are a
concern.
Understand the global and local
burden of chronic diseases.
Understand basic concepts in
chronic disease epidemiology.
Understand the implication of these
chronic diseases in relation to health
and development at the global,
country and family level
Module Outcomes

Understand the basic
epidemiological concepts related
to chronic diseases

Make a reasonable argument
why chronic diseases are a
concern globally
READINGS
There are four relevant readings for this session.
World Health Organisation. (2010). Ch 1 - Burden: Mortality, Morbidity and Risk
Factors. Global Status Report on Non-communicable Diseases 2010. Geneva:
WHO: 9-32. You will find this chapter in your Reader. The whole publication is on
your DVD.
World Health Organisation. (2011). Non-communicable Diseases Country Profiles
2011. Geneva: WHO: 1-30. You will find this section in your Reader. The whole
publication is on your DVD.
Suhrcke, M., Nugent, R.A., Stuckler, D. & Rocco, L. (2006). Ch 3: Economic
Consequences of Chronic Diseases. Chronic Disease: An Economic Perspective.
London: Oxford Health Alliance: 17-29. You will find this chapter in your Reader.
The whole publication is on your DVD.
World Health Organization. (2005). Preventing Chronic Diseases: A Vital
Investment. Geneva: WHO. 74-79.
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DEFINING CHRONIC DISEASE
TASK 1 – Develop your own definition of chronic diseases
(a)
As health workers, we encounter many different types of diseases: in
your understanding, what is a ‘chronic disease’?
What conditions fall within the category of ‘chronic disease’? List a few
that you know of.
(b)
FEEDBACK
(a) According to the World health Organisation, chronic diseases are
diseases of long duration and generally slow progression. So once
someone has the condition they will have to manage and control it.
Although HIV and AIDS will not be discussed in this module, it is important
to note that this disease is also chronic. However in this module we will
be discussing chronic diseases that are ‘non communicable’. Non
communicable means non infectious; therefore the conditions that we will
be referring to in this module are non infectious. Internationally, these
diseases are also referred to as ‘non communicable diseases’ or
‘degenerative diseases’.
(b) Chronic diseases include cancers, diabetes, hypertension and chronic
respiratory diseases such as emphysema. All these are non
communicable diseases. As mentioned, HIV and AIDS is also chronic;
however it can be transmitted from one person to the next.
A definition of chronic disease
Chronic diseases have been defined as diseases that have “a prolonged course,
do not resolve spontaneously and for which a complete cure is rarely achieved”
(Brownson et al, 1998). These are some of their major features:
They have an uncertain etiology: no direct causes have been identified for the
emergence of these diseases; studies show relationships between the
emergence of the disease and exposure to certain factors referred to as ‘risk
factors’. A cluster of factors, such as the ones mentioned above, are shown to
have a strong predictive relationship to these diseases, even if exposure to these
factors does not necessarily lead to such disease; for the chronic diseases we
are focusing on, major risk factors relate to life conditions and practices. This is
one of the major contributions of the field of epidemiology - establishing causal
relationships between the emergence of the disease and factors that the affected
persons have been exposed to.
-
They have multiple risk factors: unlike most infectious diseases they result
from exposure to several risk factors;
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They have a long latency period: the disease proceeds over a long course
of time without symptoms;
They show a prolonged course of illness;
They are generally non-contagious in origin;
They result in functional impairment or disability;
They are incurable;
They require long-term and systematic approach to treatment.
Do the conditions you identified have these characteristics? Can we add any
more characteristics to this list?
TASK 2: Identify some of the implications of the burden of chronic disease
The definitions above present a picture of the nature of chronic disease. What
then might be the implications of chronic disease?
 What costs or losses might a chronic disease predispose one to? Think of
costs, or the burden of suffering that chronic disease presents individuals,
families and the society at large. You may categorise your response
according to these affected populations.
 What opportunities does this picture show us for arresting the course of
disease?
FEEDBACK
Key issues to consider include the length of time the illness is present (a lifetime
burden); the implication of learning to live with the disease; the absence of a
known direct cause, which implies a more wide-ranging approach in treatment
and prevention; the possibility of living with the disease without knowing that one
is affected; a high cost of treatment is implied, as well as a lifelong systematic
approach to containing the course of the disease. There is a measure of
containment in this type of disease, since they are not infectious. And on the
positive side, there is the fact that something is known about the predisposing
factors; this might show an opportunity, a gap, for fighting the disease.
As we have mentioned, we shall mainly focus on the cluster of diseases that in
the past were referred to as ‘diseases of lifestyle’ due to the apparent relationship
of the disease to behavioural patterns. This phrase is out of favour nowadays in
recognition of the fact that ‘blaming the victim’ does not take adequate account of
the wide range of predisposing risk factors, some of which have their roots in the
environments of the affected.
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HOW BIG IS THE PROBLEM OF CHRONIC DISEASE?
It is estimated that a total of 57 million deaths occurred worldwide during 2008
and 63% of these deaths were due to NCDs, principally cardiovascular
diseases, diabetes, cancer and chronic respiratory diseases. In addition, a
majority of these NCD deaths (80%) occurred in low- and middle-income
countries.
The World Health Organization projects that NCDs will be responsible for a
drastically increased total number of deaths in the next decade. It was projected
that NCD deaths will increase by 15% globally between 2010 and 2020, resulting
in 44 million deaths. It is said that the greatest increases will occur in the WHO
regions of Africa, South-East Asia and the Eastern Mediterranean, where they
will increase by over 20 % (Global status report on non communicable diseases
2010)
Figure 1: Total deaths by broad cause group, by WHO Region, World Bank income group and by
sex, 2008 (Source, WHO, 2011)
If one looks carefully at these chronic NCD deaths you will find that cardiovascular diseases followed by cancers are the biggest contributors of NCD
deaths amongst those under the age of 70, as shown figure 2 on the next page.
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Figure 2: Proportion of global NCD deaths under the age of 70, by cause of death, 2008
(Source, WHO, 2011)
Read the following text, which gives more detail about Fig. 2.
READING
World Health Organisation. (2010). Ch 1 - Burden: mortality, morbidity and risk
factors. Global Status Report on Non-communicable Diseases 2010. Geneva: WHO: 932.
Now do the next reading, followed by Task 3.
READING
World Health Organisation. (2011). Non-communicable Diseases Country Profiles 2011.
Geneva: WHO: 1-30.
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TASK 3: Identify prevalent chronic diseases
Now that you have an overview on chronic diseases, refer to the NCD country
profile 2011 presented by WHO to answer the following questions:
 What chronic NCDs are prevalent in your country / community?
 Prioritize them from the most urgent to the least urgent.
 How does your country compare to other countries within the same income
group?
FEEDBACK
This task begins to address the questions presented in Assignment 1.
5 WHO IS AFFECTED BY CHRONIC DISEASES?
TASK 4: Evaluate a statement about chronic diseases
Consider this statement: ‘Chronic diseases are diseases of affluence’
Now that you have looked at the magnitude of chronic NCDs, take time to try
and understand the route through which chronic diseases manifest themselves
in communities. Reflect on the statement above and answer the following
questions, after reading the section below:




Can chronic NCDs really still be considered ‘diseases of affluence’?
Do chronic NCDs only affect rich countries?
Do chronic NCDs affect only the rich in rich countries?
Are chronic NCDs a problem only for the elderly?
Advances in medical technology have resulted in people living longer and
therefore the ageing population increases. In many parts of the world, especially
developed countries such as Sweden where they have high proportion of ageing
population, the prevalence of NCDs tends to be higher.
Previously Chronic NCDs were known as diseases of affluence. However,
current data shows that low- and middle-income countries now have the highest
mortality rates due to NCDs, which suggests a change in NCD trends. Vulnerable
and disadvantaged communities also tend to have lower life expectancy than
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people from higher social classes – determined by education, occupation,
income, gender and ethnicity.
Figure 1 shows this phenomenon explicitly. The question is why are we
observing this trend? Session 4 in Unit 1 will show the factors that are propelling
this trend. The drivers include globalisation, urbanisation and physical inactivity,
to name a few. For example in South Africa black urban women have the
highest prevalence of obesity which puts them at risk of NCDs.
6
BURDENS ASSOCIATED WITH CHRONIC DISEASES
Chronic NCDs have been said to place a burden on individuals, families, health
systems and the economy, brought about by loss of independence, loss of
income, increased budget for medication and loss of economically active
workforce.
After reading the following text about the economic effects of chronic disease,
answer the questions in the task below:
READING
Suhrcke, M., Nugent, R.A., Stuckler, D. & Rocco, L. (2006). Chapter 3: Economic
consequences of chronic diseases. Chronic Disease: An economic perspective.
London: Oxford Health Alliance: 17-29. You will find this chapter in your Reader. The
whole publication is on your DVD.
TASK 5: Consider the costs and effects of chronic diseases
1. What have the authors listed as direct, indirect and intangible cost of
chronic diseases?
2. What are the effects of chronic diseases on labour supply and productivity
(workforce)?
Effects on the individual and family
People living with chronic diseases are affected socially and economically.
Chronic disease has major adverse effects on the quality of life of affected
individuals; it causes premature death, creates significant adverse, and
underappreciated, economic effects on families, communities and societies in
general.
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Effects on the workforce
In Tough Choice: Investing in Health for Development, the World Health
Organisation warns of some of the risks posed by NCDs, and consequent higher
morbidity levels:
Increased morbidity will also reduce productivity and limit individuals’ capacity
to participate in the labour force. Coping mechanisms - such as removing
young girls from education to care for a sick family member – should also be
factored into the cost (WHO: 118).
Chronic diseases have not only social, but also economic effects. A significant
proportion of affected people are those of working age – family breadwinners and
people who should be productive members of the economy. In addition, in the
case of chronic disease there is a need for regular visits to the health facility,
which impacts on time at work, and productivity. Healthier individuals are less
likely to be absent from work.
TASK 6: Think about the burden of chronic diseases
Think of people that you have seen with any of the chronic NCDs. Think about
the effect these diseases have on the individual, family, society and health
services.

Make brief notes under the following headings:
- Effects on the individual
- Effects on the family
- Effects on the health services

Discuss the coping mechanisms you see occurring within families and the
working environment, to withstand the conditions brought about by the
burden of chronic diseases in your area.
FEEDBACK
Compare your notes with the points made in this reading.
READING
World Health Organization. (2005). The Economic Impact of Chronic Diseases.
Preventing Chronic Diseases: A vital investment. Geneva: WHO: 74-79
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THE IMPACT OF CHRONIC DISEASES ON HEALTH SERVICES
Chronic diseases threaten to overwhelm already over-stretched health services.
While historically the health care system has focussed on treating acute
illnesses, today there is growing pressure for the health care system to effectively
manage the increasing number of chronic disease sufferers as well. Chronic
conditions are long-term illnesses that limit life activities and require ongoing
care. Yet many people do not have access to ongoing medical attention,
especially in developing countries, and particularly in the African region where
resources are scarce. Lives are then lost due to the fact that acute care models
and available services cannot accommodate the needs of chronically ill
individuals. These are often people from the most needy groups, where the result
is further increased stress on families due to loss of breadwinners.
TASK 7: Consider the case of South African health services
Bearing in mind the strain on health services brought about by the burden of
chronic diseases, explain the South African health service status within a
developing country, and highlight how you see health systems accommodating
people from different socio-economic statuses (especially the poor).
FEEDBACK
Compare your answers with the WHO article, Tough Choices: Investing in health
for development.
8
SESSION SUMMARY
In this session we have introduced you to chronic diseases and defined related
concepts. In addition we have looked at the magnitude of chronic NCDs and the
people affected by these conditions. We have further highlighted the global
spread of NCDs dispelling assumptions that certain parts of the world are
completely unaffected by chronic NCDs. We have looked at the implications or
consequences of chronic NCDs. Consequences of NCDs include its effects on
the individuals, families, the workforce and the health services.
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Unit 1 - Session 2
Demographic,
epidemiological and nutrition
transition
Introduction
The main concerns in developing countries have always been the high
prevalence of health problems traditionally associated with poverty and underdevelopment such as nutritional, peri-natal, maternal and infectious diseases
which lead to high mortality rates. With increasing urbanization, and the
concomitant changes in life circumstances (including dietary, physical activities
and social habits), the prevalence of chronic diseases like non-insulin-dependent
(type II) diabetes mellitus (NIDDM), hypertension and cardiovascular diseases
have increased in the developing world. The result is that in the last few decades,
there have been major health changes in developing countries. These changes
have been described as the demographic, epidemiological and nutrition
transition.
In this session the terms will be explained.
Contents
1.
2.
3.
4.
Learning outcomes of this session
Readings
Demographic, epidemiological and nutrition transition
Session summary
Timing of this session
In this session there are four readings and one task. It should take you at least
one hour to finish the session.
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LEARNING OUTCOMES OF THIS SESSION
In the course of this session, you will be addressing the Session Outcomes in
the left column; they relate to the Module Outcomes indicated in the right
hand column:
Session Outcomes
Module Outcomes



2
Differentiate between the
demographic, epidemiological and
nutrition transitions.
Explain chronic diseases in
developing countries in relation to
demographic, epidemiological and
nutrition transition.
Describe epidemiological transition
incorporating social, behavioural,
cultural and environmental factors
READINGS
There are four readings for this session. You will be referred to them in the
course of the session.
Popkin, B. M. (2004). The Nutrition Transition: An Overview of World Patterns of
Change. Nutrition Reviews, 62(2): S140–S143.
Vorster, H.H., Bourne, L.T., Venter, C.S. & Oosthuizen, W. (Nov 1999). Contribution
of Nutrition to the Health Transition in Developing Countries: A Framework for
Research and Intervention. Nutrition Reviews, 57 (11): 341-349.
Omran, A.R. (1971). The Epidemiologic Transition: A Theory of the Epidemiology of
Population Change (Extract). The Milbank Quarterly, 49 (4): 509-538, in Bulletin of
the World Health Organisation,(2001). 79(2): 161-170.
Hawkes, C. (2006). Uneven Dietary Development: Linking the Policies and Process of
Globalisation with the Nutrition Transition, Obesity and Diet-Related Chronic
Diseases. Globalisation and Health, 2(4): 18 pages. BioMed Central Public Health,
2:2: 1-9. [Online]. Available: www.biomedcentral.com/2/14 [Downloaded:
10/7/07].
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DEMOGRAPHIC, EPIDEMIOLOGICAL AND NUTRITION
TRANSITION
Demographic transition
Demographic transition refers to a shift from a pattern of high fertility and high
mortality to one of low fertility and low mortality, typical of modern and
industrialised nations. These changes occur as a result of improved socioeconomic conditions, including increases in income of the population, improved
education and employment status.
Epidemiological transition
Epidemiological transition describes the shift from a pattern in which pestilence,
famine, and poor sanitation lead to a high prevalence of infectious diseases and
malnutrition, to a pattern in which the prevalence of chronic and degenerative
diseases is high. These changes are due to the decline in fertility rates, mortality
rates and infectious diseases, as well as a bigger aging population. This results
in a shift in the cause of death profile. The epidemiological profiles of developing
countries increasingly reflect diseases and health problems of adults rather than
those of children. In particular, chronic and degenerative diseases, and accidents
and injuries, become more prominent in the disease burden of populations. The
transition occurs at different paces in different places, depending on the rate of
fertility change, the distribution of risk factors that contribute to the incidence of
disease, and the health system’s ability to respond to the changing
epidemiological profile.
The epidemiological transition combined with the demographic transition has
become known as the health transition.
Historically, in developed countries during industrialisation and the accompanying
economic growth spurt, these countries experienced a health transition which led
to the increase of chronic diseases. Developing countries that are experiencing
rapid urbanisation are experiencing a health transition often characterised by a
double burden of disease: infectious diseases and undernutrition remain
important health problems, with chronic diseases also becoming more prevalent.
Nutrition transition
Nutrition transition is closely related to the health and demographic transition. It is
defined as a sequence of characteristic changes in dietary patterns and nutrient
intakes associated with social, cultural and economic changes during the
demographic transition. The nutrition transition has been associated with higher
rates of coronary heart disease, some kinds of cancer, obesity and non-insulindependent diabetes mellitus. The traditional diet in most developing countries
has a starchy or carbohydrate-rich basis that is also high in fibre, while protein
(especially animal protein) and fat intakes are low. With development and
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urbanization this diet is replaced by Western diet, which is high in saturated fats,
animal protein and sugar, and low in fibre.
Most often, these changes in diet have been ascribed to the rise in socioeconomic status (SES) as a result of industrialisation and economic growth.
As a result of changes in the way we eat and live, some chronic diseases are
increasingly affecting both developed and developing countries. Indeed, dietrelated chronic diseases - such as obesity, diabetes, cardiovascular disease,
cancer, dental disease, and osteoporosis - are the most common cause of death
in the world and present a great burden for society. In what is known as the
nutritional transition, traditional plant-based diets including foods such as cereals
and potatoes are increasingly being replaced by diets that are richer in added
sugars and animal fats. This transition, combined with a general trend towards a
more sedentary lifestyle, is an underlying factor in the risk of developing chronic
diseases.
The average food consumption (in terms of calories) appears to have increased
steadily in countries around the world, particularly in developing countries,
though not in sub-Saharan Africa. The average fat content of the diet is also
increasing throughout the world, and it is especially high in parts of North
America and Europe. An increasingly large portion of this fat comes from animal
products and vegetable oils. Factors such as rising incomes and population
growth have raised the demand for animal products like meat, dairy products,
and eggs. These products provide high-value protein and many essential
nutrients, but excessive consumption can lead to excessive intakes of fat.
READINGS
Popkin, B.M. (2004). The Nutrition Transition: An Overview of World Patterns of Change.
Nutrition Reviews, 62 (2): S140–S143,
Vorster, H.H., Bourne, L.T., Venter, C.S. & Oosthuizen, W. (Nov 1999). Contribution of
Nutrition to the Health Transition in Developing Countries: A Framework for Research
and Intervention. Nutrition Reviews, 57 (11): 341-349.
Omran, A.R. (1971). The Epidemiologic Transition: A Theory of the Epidemiology of
Population Change (Extract). The Milbank Quarterly, 49 (4): 509-538, in Bulletin of
the World Health Organisation,(2001). 79(2): 161-170.
Hawkes, C. (2006). Uneven Dietary Development: Linking the Policies and Process of
Globalisation with the Nutrition Transition, Obesity and Diet-Related Chronic Diseases.
Globalisation and Health, 2(4): 18 pages. BioMed Central Public Health, 2:2: 1-9.
[Online]. Available: www.biomedcentral.com/2/14 [Downloaded: 12/08/10].
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TASK 1: Use the readings to answer questions about transition

Give an outline of the role played by urbanization on individuals’ behaviours
(e.g. diets and physical activity), as well as health in developing countries.

Outlines the Stages of the Nutrition Transition (this should include health,
nutritional and demographic changes).

What are the policy and planning implications of the demographic,
epidemiological and nutritional transition for a developing country?
FEEDBACK
Now that you have answered the questions in Task 1 above, compare your
discussion with the information given in the above prescribed readings.
4
SESSION SUMMARY
This session has introduced the concepts of demographic, epidemiological and
nutritional transition – these are critical concepts in understanding the emergence
of and the problem of chronic non communicable diseases. Do you feel you
understand adequately what is meant by these concepts? Could you describe
them to someone else, as well as explain how these transitions contribute to non
communicable chronic disease? Understanding these transitions leads us to a
better understanding of the mechanisms by which chronic non communicable
diseases develop in populations. Having an understanding of these mechanisms
is helpful and will assist in devising interventions that are likely to be effective.
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Unit 1 - Session 3
Social Determinants of
health and noncommunicable diseases
Introduction
How do chronic diseases develop? Most have no clear- cut process of causation,
and most are found to require the presence of a number of factors before they
can develop. Studies have led to the recognition of a number of risk factors that
predispose a person to chronic disease.
At every stage of life, health is determined by complex interactions between
social and economic factors, the physical environment and individual behaviour.
These factors are referred to as ‘Social Determinants of Health’. They do not
exist in isolation from one another. It is the combined influence of the
determinants of health that determines health status of individuals.
Understanding the interactions of these determinants is therefore very important
in planning community interventions. In this session, we are going to discuss the
key social determinants of health and their association to chronic non
communicable diseases.
Contents
1.
2.
3.
4.
5.
6.
7.
Learning outcomes of this session
Readings
Understanding the key determinants of health
The link between diet and chronic diseases
The link between physical inactivity and chronic diseases
Tobacco use and chronic diseases
Session summary
Timing of this session
In this session there are five readings and five tasks. It should take you at least
two hours to finish the session.
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LEARNING OUTCOMES OF THIS SESSION
In the course of this session, you will be addressing the Session Outcomes in
the left column; they relate to the Module Outcomes indicated in the right
hand column:
Session Outcomes




2
Understand the social determinants
of health
Identify factors that contribute to
chronic diseases
Describe the role played by these
factors in the development of chronic
diseases
Group them according to modifiable
and non-modifiable
Module Outcomes

Understand the basic
epidemiological concepts related
to chronic diseases

Describe and analyse the
modifiable and non-modifiable
risk factors for chronic diseases

Critically analyse barriers to the
implementation of global
strategies for the prevention and
control of CNCDs in order to
develop local preventive
strategies
READINGS
There are five readings for this session.
Vorster, H.H., Bourne, L.T., Venter, C.S., Oosthuizen, W. (1999). Contribution of
Nutrition to the Health Transition in Developing Countries: A Framework for Research
and Intervention. Nutrition Reviews. November: 57 (11). 341-349
Lee, I.M., Shiroma, E.J., Lobel, F., Puska, P., Blair, S.N., Katzmarzyk, P.T. & the Lancet
Physical Activity Series Working Group. (2012). Effect of Physical Inactivity on Major
Non-communicable Diseases Worldwide: an Analysis of Burden of Disease and Life
Expectancy. Lancet 380: 219–229
Booth, K.M., Pinkston, M.M., Poston, W.S.C. (2005). Obesity and the Built Environment.
Journal of American Dietetic Association, 105: s110-s117
Jha, P. (2009). Avoidable Cancer Deaths and Total Deaths from Smoking. Nature
Reviews, 9: 655-664
Beaglehole, R. & Yach, D. (2003). Globalization and the Prevention and Control of Noncommunicable Diseases: The Neglected Chronic Diseases of Adults. The Lancet, 363: 903
- 908.
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UNDERSTANDING THE SOCIAL DETERMINANTS OF HEALTH
There is a growing understanding that many of the health problems that we are
currently experiencing in the world can be attributed to social conditions in which
people live and work. This means that in order to tackle many health problems
we therefore need to focus on ‘the cause of the cause’.
Adapted from Whitehead & Dahlgren, 1991
The diagram above is an illustration of the factors that determine health. These
factors tend to interact and are intertwined.
Ill health of the poor and the social gradient in health within countries and distinct
health inequities between and within countries are caused or driven by:
1. Structural factors sometimes referred to as distal factors include
unequal distribution of power, income, goods and services both
globally and nationally
2. Individual level factors sometimes referred to proximal factors,
which are the factors that are most glaring and therefore more
obvious. They include access to health care, schools, education,
conditions of work/leisure, homes, communities, towns, or cities.
These factors tend to inhibit an individual’s chances of leading a
flourishing life.
The structural determinants together with the daily life conditions form the social
determinants of health.
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Framework of the major categories and pathways of determinants of health
inequities and well-being
Source: WHO Commission on Social Determinants of Health, August 28 2008
The Framework of the major categories and pathways of determinants of health
inequities and well-being suggests that there is a need for a multi and
intersectoral approach to addressing the determinants of health. In addition it
further highlights the role of departments of health in policy development in other
sectors, as these tend to have an influence on health.
Numerous studies over the years have shown a link between certain factors and
the ultimate development of chronic disease. These are the risk factors. We will
look at three that are linked to such chronic diseases as diabetes, hypertension
and cardiovascular diseases; these are diet and nutrition, inadequate physical
activity (a sedentary lifestyle) and obesity. You will notice that these risk factors
are to a certain extent related to individual behaviours and are proximal in nature
and therefore more amenable to change. Chronic diseases are not caused by
individual lifestyle factors alone – the prevailing belief patterns and systems, the
living environment, as well as genetic / biological factors are also implicated.
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4
THE LINK BETWEEN DIET AND NUTRITION AND CHRONIC
DISEASES
Diet, nutrition and chronic disease
The impact of diet on the development of chronic diseases is well established,
with dietary guidelines focussing on limiting foods high in salt, sugar and fat, and
emphasizing the intake of whole grains, fruit and vegetables. For example, overconsumption of fat and sugar accelerates weight gain to the extent that body fat
accumulation becomes excessive; this is a condition known as obesity. Obesity
has been identified as the major risk factor for the development of chronic
diseases later in life (diabetes and hypertension in particular).
Both what is eaten and how much contribute in different ways to the development
of chronic disease. However, food is a very important part of human life, and as
such is subject to many beliefs and practices. Cultural beliefs, traditions, and
ethnic preferences exert a strong influence on diet. For example, in some
cultures and ethnic groups cooking methods such as barbequing, drying and
smoking are a norm. These involve the overuse of salt in preparation and also
promote the consumption of meat very high in fat. Barbequing in particular uses
cuts with visible fat as lean meat does not barbeque well.
Acculturation has been identified as the most powerful factor influencing people’s
diets, through food availability, cost, convenience, time constraints and dietary
knowledge, which influence food selection and preparation.
Poor communities are particularly affected where there are money constraints
and food is scarce, and where people rely on vendors or tuck-shops for their
daily food supply, with the food on offer not necessarily good or healthy, yet very
costly. Time constraints sometimes force people to make a decision to eat out or
make use of take-away convenience foods.
The reading below illustrates the relationship between nutrition and the
development of chronic diseases. Read this text before tackling the Task 1.
READING
Vorster, H.H., Bourne, L.T., Venter, C.S., Oosthuizen, W. (Nov 1999). Contribution of
Nutrition to the Health Transition in Developing Countries: A Framework for Research
and Intervention. Nutrition Reviews, 57 (11): 341-349.
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TASK 1: Outline factors that influence diet and nutrition
1. What are some of the factors that influence diet and decisions about food
and eating in populations in general?
2. What factors influence food and eating in communities with adequate or
plenty of money to spend?
3. What factors influence food and eating in communities with less money, if
different from the above?
4. Can people be influenced to change their way of eating by outside agents,
e.g. health workers?
5. Does your health service have accurate, reliable data on food and eating
practices in the communities it serves and do you think it is the role of a
health service to concern itself and spend resources on such an issue?
FEEDBACK
Food availability, beliefs about food and eating, beliefs about body size, common,
or traditional practices are all factors that influence diet and decisions about food
and eating. Compare your responses with the information in the article you read,
and any other relevant references you can find.
5
THE LINK BETWEEN PHYSICAL INACTIVITY AND CHRONIC
DISEASES
TASK 2: Think about ‘physical activity’
Before we highlight the role played by physical inactivity on the development
of chronic NCDs, please take time to think about physical activity:
 What would you consider as physical activity?
 Some people do not exercise. Please outline the reasons why they do not
exercise.
 How difficult is it to exercise? Outline some barriers to performing physical
activity.
FEEDBACK
Physical activity covers all forms of work or movement in which the person uses
all or most parts of the body. In this way, domestic and all forms of manual work,
as well as exercise, are all forms of physical activity. Chronic disease prevention
focuses on exercise as physical activity due to the general lack of arduous
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physical work as part of the daily activity of many people in a modern urban
setting.
Now read the reading by Lee and colleagues to get a better understanding of the
effect of physical activity on chronic NCDs.
READINGS
Lee, I.M., Shiroma, E.J., Lobel, F., Puska, P, Blair, S.N., Katzmarzyk, P.T. & the
Lancet Physical Activity Series Working Group. (2012). Effect of Physical Inactivity on
Major Non-communicable Diseases Worldwide: an Analysis of Burden of Disease and
Life Expectancy. Lancet, 380: 219–29.
Inadequate physical activity and chronic disease
Physical activity is recognised as one of the risk factors for the chronic NCDs
including hypertension, cardiovascular diseases, diabetes and cancer. The cost
associated with physical inactivity is borne by taxpayers, employers, and
individuals in the form of higher taxes to subsidize public insurance programs
and increased health insurance premiums.
Recent studies estimate that 6-10% of the burden of major non communicable
diseases such as coronary health diseases, type 2 diabetes and breast and
colon cancers can be attributed to physical inactivity. In addition, it is estimated
that in 2008, 9% of premature deaths or more than 5.3 of the 57 million deaths
were due to physical inactivity. Physical activity is one of those modifiable
behaviours that, if adopted, appears to be protective of chronic diseases by
acutely lowering blood lipid concentrations, improving tissue sensitivity to insulin,
decreasing blood clotting, increasing good cholesterol while reducing bad
cholesterol, lowering blood pressure and increase life expectancy.
Research relating to the determinants of physical inactivity has previously
focused on individual level factors, largely neglecting structural factors such as
physical environments, which also influence physical activity. It is now
acknowledged that environments in which live provide potential opportunities and
barriers to engaging in physically activity. Research aimed at understanding how
elements of the natural and built environment influence physical activity is now
increasing. For example, it has been shown that suburban sprawl and the way
neighbourhoods are designed are related to the physical health and bodyweight
status of adults residing in those neighbourhoods.
Findings of existing primary studies and narrative reviews studying the
associations between the perceived environment and physical activity are
ambiguous. Perceptions of neighbourhood crime have also been found to have a
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negative association with physical activity, in that the more crime increases in
the area, the less people walk to and from places.
Although physical inactivity is a behavioural factor there are factors that are
beyond the individual’s control that may either hinder or enhance physical
activity.
To assist you in answering the questions below, refer to the reading by Booth et
al.
READING
Booth, K.M., Pinkston, M.M., Poston, W.S.C. (2005). Obesity and the Built
Environment. Journal of American Dietetic Association, 105: s110-s117.
TASK 3: What are the influences on and barriers to physical activity?

How does the built environment hinder or enhance physical activity in
communities? .

What are some of the more practical ways that people can employ in order
to adopt physical activity in your own setting?
FEEDBACK
Evaluate and modify your answers in accordance with the readings above.
6
THE LINK BETWEEN TOBACCO AND CHRONIC
DISEASES
Over one thousand million people worldwide smoke tobacco. The percentage of
smokers has decreased in developed countries, but is increasing in developing
countries and especially among women. Tobacco is mainly smoked as
cigarettes, but also as pipes or cigars. All current tobacco products expose
smokers to chemicals which can cause cancer. The amounts of harmful
substances to which smokers are exposed depend on the type of tobacco, the
way it is smoked, product design and whether filters are used.
Tobacco smoking strongly increases the risk of developing cancer of the lung,
oral cavity (mouth), pharynx and larynx, oesophagus, pancreas, bladder and
renal pelvis (the kidney outlet). It also increases the risk of cancer of the nasal
cavities (nose) and sinuses, stomach, liver, kidney, cervix (neck of the uterus)
and bone marrow (myeloid leukaemia). Active smoking can cause pregnancy
problems, as well as diseases of the respiratory and cardiovascular system.
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Smoking can also cause changes in the metabolism of cells or tissues, resulting
in changes to the way foreign substances that are broken down by the body.
Read the two texts in the box below. In Beaglehole & Yach (2003), note the facts
in Table 2 (p5), and the preceding section on ‘Globalisation and the tobacco
pandemic’. In the reading by Jha (2009), take particular note of smoking patterns
and increasing cessation rates (p655-661).
READINGS
Beaglehole, R. & Yach, D. (2003). Globalization and the Prevention and Control of
Non-communicable Diseases: The Neglected Chronic Diseases of Adults. The Lancet,
363: 903 - 908.
Jha, P. (2009). Avoidable Cancer Deaths and Total Deaths from Smoking. Nature
Reviews, 9: 655-664
TASK 4: Think about some key factors relating to smoking
After reading the two texts above, explain:
 What are the trends in active smoking worldwide?
 What are some of the measures that have been undertaken to control the
use of tobacco?
 Outline the benefits of reducing major risk factors.
Many of the individual level factors or determinants that have been highlighted in
the section above such as physical inactivity, nutrition and smoking are factors
that can be modified. However there are other factors that have been linked to
the development of many chronic NCDs that are non- modifiable. In the next
task you are required to think carefully about modifiable and non- modifiable
determinants and thereafter categorise determinants accordingly.
To help you with the following task, refer to the section on social determinants of
health in your Health Promotion module.
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TASK 5: Rating factors that influence health


Think of all the factors that influence or determine your health / illhealth. Jot them down and rank them according to which ones you think
are the most important or have the most influence on your health.
Which ones do you have control over (can modify) and which ones you do
not have control over (non-modifiable)?
Modifiable

Non-modifiable
Consider how these factors could determine and change your weight
status, and how these changes in weight status would impact on your
health status (e.g. the development of hypertension / diabetes mellitus
etc.)?
FEEDBACK
The notion of ‘determinants of health’ refers to the most important factors that
have a key influence on health; that can determine whether one enjoys good
health or ill health. Compare your determinants of health with the information in
the diagram on page 21 above.
7
SESSION SUMMARY
This session looked at the social determinants of health, and selected risk factors
for NCDs which tend to affect individuals. Understanding the determinants of
health gives insight into the appropriate prevention strategies that need to be
employed at the different levels both nationally and globally. This session should
prepare you to start thinking of the strategies that are required to combat NCDs.
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