The Epidemiology of Chronic Diseases: An overvie€¦ · Web viewThe Epidemiology of Chronic Diseases: An . Overview. Introduction. That you have chosen this module suggests that

The Epidemiology of Chronic 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 diseasesStudy Session 2: Demographic, epidemiological and nutrition transitionStudy 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

SOPH, UWC, Master of Public Health: Epidemiology and Control of Non-communicable Diseases – Unit 11

UNIT1


Unit 1 - Session 1Introduction: Epidemiology and implications of Chronic Non Communicable DiseasesSOPH, UWC, Master of Public Health: Epidemiology and Control of Non-communicable Diseases – Unit 1

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Contents

1. Learning outcomes of this session2. Readings3. Defining chronic disease4. How big is the problem of chronic diseases?5. Who is affected by chronic diseases?6. Burdens associated with chronic diseases7. The impact of chronic diseases on health services 8. 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.


1 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 Module Outcomes 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

Understand the basic epidemiological concepts related to chronic diseases

Make a reasonable argument why chronic diseases are a concern globally

2. 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.


3 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’?

(b) What conditions fall within the category of ‘chronic disease’? List a few that you know of.

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 diseaseChronic 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;


- 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.


4 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 diseases2010)

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.


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: 9-32.

Now do the next reading, followed by Task 3.

READING

World Health Organisation. (2011). Non-communicable Diseases Country Profiles 2011. Geneva: WHO: 1-30.


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


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 familyPeople 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.


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.

FEEDBACKCompare 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


7 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.


Unit 1 - Session 2Demographic, epidemiological and nutrition transitionIntroduction

The main concerns in developing countries have always been the high prevalence of health problems traditionally associated with poverty and under-development 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. Learning outcomes of this session2. Readings3. Demographic, epidemiological and nutrition transition4. Session summary


In this session there are four readings and one task. It should take you at least one hour to finish the session.


1 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 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

2 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].


http://www.biomedcentral.com/2/14


3 DEMOGRAPHIC, EPIDEMIOLOGICAL AND NUTRITION TRANSITION

Demographic transitionDemographic 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 socio-economic conditions, including increases in income of the population, improved education and employment status.

Epidemiological transitionEpidemiological 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 transitionNutrition 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-insulin-dependent 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


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 socio-economic 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, diet-related 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].


http://www.biomedcentral.com/2/14

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?

FEEDBACKNow 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.


Unit 1 - Session 3Social Determinants of health and non- communicable 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. Learning outcomes of this session2. Readings3. Understanding the key determinants of health 4. The link between diet and chronic diseases5. The link between physical inactivity and chronic diseases6. Tobacco use and chronic diseases7. Session summary


In this session there are five readings and five tasks. It should take you at least two hours to finish the session.


1 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 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

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

2 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 Non-communicable Diseases: The Neglected Chronic Diseases of Adults. The Lancet, 363: 903 - 908.


3 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.


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.


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, over- consumption 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.

READINGVorster, 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.


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?

FEEDBACKFood 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 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.

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.


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.

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 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?

FEEDBACKEvaluate 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. 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.


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.


TASK 5: Rating factors that influence health

Think of all the factors that influence or determine your health / ill-health. 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.)?

Documents

The Epidemiology of Chronic Diseases: An overvie€¦ · Web viewThe Epidemiology of Chronic Diseases: An . Overview. Introduction. That you have chosen this module suggests that