Lifestyle and Disease
Transcript of Lifestyle and Disease
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What is a disease?
What is a disease?
An abnormal condition of an
organism that impairs its function
and which is accompanied by a
set of characteristic signs and
symptoms.
A disease is different from
physical trauma due to an
accident (e.g. breaking a rib in a
fall).
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Classifying diseases
Diseases can be classed in several ways:
by timescale – acute (develops quickly and lasts a shorttime, e.g. acute angina) vs. chronic (develops slowly and
lasts a long time, e.g. chronic bronchitis)
by number of causes – single factor (have a single
cause, such as a single mutated gene, e.g. sickle-cell
anaemia,) vs. multifactorial (have many causes, genetic
and environmental, e.g. cardiovascular disease).
Diseases can also be classified according to whether theyare infectious (e.g. HIV), non-infectious (e.g. lung cancer),
inherited (e.g. cystic fibrosis), caused by a deficiency (e.g.
scurvy), a mental disorder (e.g. schizophrenia), etc.
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UK deaths, 2005
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Genetics and environment
Many non-infectious diseases develop as a result of the
interaction between a person‟s environment/lifestyle and their
genes – they are multifactorial diseases.
These diseases have a genetic component, which means
they may be:
partly inherited – inheriting the „faulty‟ genes will make yougenetically predisposed (more susceptible) to develop
the disease, but environmental factors still play a role.
Examples include heart disease, cancer and Alzheimer‟s.
completely inherited – inheriting the „faulty‟ genes is
certain to make you develop the disease. Examples
include cystic fibrosis and Huntington‟s chorea.
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Calculating the risk of diseases
In 2005 in the UK, 100,936 people died from coronary heart
disease (CHD), and the population was 60,209,500. Whatwas the risk of death from CHD in the UK in 2005?
= 0.0017
= 0.17%
= 1 in (60,209,500 / 100,936)
= 1 in 597
Risk = 100,936 in 60,209,500 Or, risk = 1 / 597
Health risks are not the same for everyone, however,
because people have different risk factors.
What is the risk of developing a disease?
no. people with the disease at any one timetotal no. people who could develop the disease
risk =
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What are risk factors?
A risk factor is anything that increases the chance of
developing a disease.
Smoking is a major risk
factor for lung cancer,
which means smokers
have a much higher riskof developing lung cancer
than non-smokers.
Risk factors are correlational with a disease, not
necessarily causal. For example, international travel is a riskfactor for malaria, but it is not the travel itself that causes
malaria – it just increases the chance of coming into contact
with the malarial parasite.
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Types of risk factor
Risk factors may be modifiable or non-modifiable.
Modifiable risk factors are
those that can be prevented and
controlled. These are essentially
environmental or lifestyle risk
factors, such as smoking, dietand physical activity.
Non-modifiable risk factors are
those that cannot be preventedor controlled. These are age and
genetic risk factors, such as
gender and family history.
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Take a vote: lifestyle and health
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is commoninvolves a spectacular outcome
is familiar is unfamiliar
is an accidentis the result of an intentional
action
occurs over the long-termoccurs over the short-term
is done voluntary by youis out of your control
Underestimate the risk of
an event if it…
Overestimate the risk of an
event if it…
Perceived risk vs. actual risk
A person‟s perceived risk of a particular event can be
markedly different from the actual risk. What factors do you
think make an event seem more risky than it actually is?
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Worldwide deaths due to CVD, 2002
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What is coronary heart disease?
Coronary heart disease (CHD) is a disease of the arteries
supplying the heart (coronary arteries). Almost one-fifth of
all deaths in the UK in 2005 were due to CHD.
The major cause of CHD is
atherosclerosis: a thickening of
arteries caused by a build-up of
fatty plaques (atheromas) on the
inside walls.
Atherosclerosis can eventuallylead to a reduced blood supply
(ischaemia) to tissues, with
potentially fatal consequences.
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Trends in CVD death rates
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Gender, age, CHD and stroke
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Scientist case study
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Development of atherosclerosis
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others: stress, alcohol
diabetes mellitus
obesity
ethnicity/racephysical inactivity
family history of the diseasetobacco smoking
male gender high blood cholesterol
advancing agehigh blood pressure
CHD risk factors
Hundreds of risk factors for CHD and stroke have been
identified. The major ones are:
Non-modifiableModifiable
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Hypertension and CHD
High blood pressure (hypertension) is a major risk factor for
CHD and other cardiovascular diseases.
Hypertension is defined as
systolic blood pressure above
140 mmHg and/or diastolic
blood pressure above 90 mmHg.
Hypertension puts strain on the
heart and blood vessels,
increasing the risk of
aneurysm or thrombosis. It issometimes called the „silent
killer‟ because it can develop
without symptoms.
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Hypertension and CHD
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Cholesterol and lipoproteins
Cholesterol is a soft waxy lipid that has a vital role as a
component of cell membranes, where it regulates fluidity.
Cholesterol is insoluble in blood, so
it is transported by lipoproteins.
These are spherical complexes
consisting of:
Two major types of lipoprotein are low-density lipoprotein
(LDL) and high-density lipoprotein (HDL).
an outer layer of phospholipids,
studded with proteins
an inner core of trigylcerides
and cholesterol.
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High blood cholesterol levels and CHD
LDLs generally transport cholesterol fr om the
liver to body tissues, depositing it on the
walls of blood vessels. In high levels,it contributes to atherosclerosis.
HDLs generally transport cholesterol away from the tissues
to the liver, where the cholesterol is metabolized. High levels
of HDL cholesterol are linked to a reduced risk of CHD.
Eating a diet high in saturated fat
is the biggest cause of elevated LDL cholesterol levels.
LDL cholesterol levels can be reduced by regular exercise,
eating plenty of fibre and a diet rich in polyunsatured fats.
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Smoking and CHD
Smoking tobacco is a major cause of CHD, and smokers are
at a higher risk of developing CVD than lung cancer.
Smoking increases the risk of CHD in several ways:
it damages and weakens the endothelial lining of blood
vessels
nicotine increases blood pressure and heart rate, andconstricts blood vessels
it increases clotting and the development of atheromas
carbon monoxide reduces the amount of oxygen that
blood can carry.
it lowers HDL cholesterol and raises LDL cholesterol levels
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Effects of CHD: heart attack
The most dangerous symptom/result of CHD is a heart attack,
known as a myocardial infarction (MI).
An MI occurs when the blood
supply to part of the heart muscle
(myocardium) is interrupted.
This causes oxygen deprivationand subsequent tissue damage.
The most common symptom is
chest pain, but shortness of breath,excessive sweating, nausea and
weakness may also be present. Loss
of consciousness and death can occur.
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Effects of CHD: angina
A less severe symptom of
CHD is angina pectoris.
This is a tight, grippingchest pain or ache, similar
to indigestion, which
commonly occurs during
physical activity.
The narrowing of the coronary arteries results in inadequate
blood and oxygen supply, forcing the heart to respire
anaerobically, and causing a build-up of lactic acid.
The pain normally subsides with rest, once the demand on
the heart has dropped and it can respire aerobically.
Di i h di
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Diagnosing heart disease
H d CHD d l ?
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How does CHD develop?
Id tif i CHD i k f t
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Identifying CHD risk factors
R d i th i k f CHD
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Reducing the risk of CHD
Ensuring a healthy lifestyle can make a significant difference
to a person‟s risk of developing CHD.
stopping smoking
These changes aim to reduce blood pressure and blood
cholesterol, and reduce weight if overweight or obese. Key
steps include:
regular cardiovascular exercise – about 30 mins of
moderate exercise several times a week
a healthy diet – low in saturated fats (including trans fats)
and salt, high in fibre, fresh fruit/vegetables, and
moderate mono/polunsaturated fats
reducing alcohol intake.
T ti CHD di ti
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Treating CHD: medication
T ti CHD
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Treating CHD: surgery
Surgery is used in the treatment or prevention of CHD, stroke
or MI. The type of operation depends on the severity and
location of atherosclerosis, and factors such as whether thepatient has diabetes.
A coronary artery bypass
graft (CABG) is an operationin which arteries from
elsewhere in the body (e.g.
legs or chest) are grafted on
to coronary arteries to
bypass blocked regions.
Single, double, triple bypass refers to the number of coronary
arteries that are bypassed.
T ti CHD i l t
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Treating CHD: coronary angioplasty
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Respiratory diseases
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Respiratory diseases
Respiratory diseases are one of the biggest causes of death
worldwide.
Respiratory diseases affect the lungs, bronchi, trachea and
throat. They can be mild (e.g. cold) or life-threatening (e.g.
pneumonia, lung cancer).
Chronic obstructive pulmonary disorder (COPD) is aterm for a group of diseases that cause a reduction in the
airflow in the lungs and which are not fully reversible.
Two of the more serious types of COPD are chronicbronchitis and emphysema, and are both usually caused
by smoking.
COPD: chronic bronchitis
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COPD: chronic bronchitis
Chronic bronchitis is a
narrowing of the bronchi. It
is characterized by:
a persistent cough that
produces phlegm - due
to an increased number
and size of goblet cells
shortness of breath and wheezing - irritants in cigarettesmoke cause inflammation in the lining of the bronchioles.
Over time this leads to scarring and narrowing of the
bronchioles, reducing airflow.
normal
airway
inflammed
airway
mucus
bronchi
COPD: emphysema
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COPD: emphysema
Emphysema is a gradual breakdown of alveolar walls and
damage to terminal bronchioles and alveolar capillaries.
This reduces the efficiency of gas exchange, causing
chronic breathlessness and hyperventilation.
Using this photo of healthy lung tissue
(left ) and emphysema
lung tissue (right ), can
you explain why gas
exchange is less
efficient in
emphysema?
Diagnosing COPD
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Diagnosing COPD
There is no one single test for COPD. Diagnosis depends
on taking into account a patient‟s risk factors (e.g. whether
they smoke, their age), their symptoms and clinical tests.
Testing the patient‟s lung
function using spirometry
is essential. It can
determine whether there is
airway obstruction and can
help exclude the possibility
of other respiratorydiseases, such as asthma
or lung cancer.
Determining lung function
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Determining lung function
Treating COPD
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Treating COPD
Stopping smoking is the single most important step in
slowing the decline in lung function in people with COPD.
Medicines commonly prescribed to treat COPD include
bronchodilators, which widen the airways by relaxing
smooth muscles, and corticosteroids, which act as anti-
inflammatories.
Oxygen therapy,
especially for people
with emphysema, may
be required for most of each day.
What is asthma?
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What is asthma?
Asthma is a chronic condition in which the airways
occasionally narrow and become inflamed, limiting airflow.
Asthma causes difficulty
breathing, wheezing and
chest tightness, and can
be mild or life-threatening.
Treatment is with bronchodilators, corticosteroids, or a
combination of the two.
Asthma is triggered by a
range of stimuli, such as
allergens, dust, exercise,
stress and infections.
Lung cancer
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Lung cancer
Lung cancer is the biggest cause of cancer-related deaths in
men and second-biggest cause in women. About 90% of
cases are caused by smoking.
Symptoms include shortness of breath, coughing (including
coughing up blood) and loss of weight.
Most incidences of lung
cancer are due to
uncontrolled growth of epithelial cells lining the
airways. Cancers arising
from these cells are
called carcinomas.
Lung cancer
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Lung cancer
Lung cancer generally develops quite slowly. By the time it
has been diagnosed, the cancer may have spread to other
areas of the body. This is called metastasis, and makes itdifficult to treat successfully.
Lung cancer can be seen
on an X-ray or a CT scan,and diagnosis is usually
confirmed after a small
sample of tissue is taken
(a biopsy) and analysed.
Like many other cancers, lung cancer is treated by surgery,
chemotherapy and/or radiotherapy.
Cancer statistics
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Cancer statistics
Smoking and lung cancer
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Smoking and lung cancer
Smoking and lung cancer: epidemiology
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Smoking and lung cancer: epidemiology
The first solid epidemiological evidence that smoking
increased the risk of lung cancer came from a 1950 study by
Richard Doll, a British doctor and epidemiologist, and AustinBradford Hill, a British epidemiologist and statistician.
Their study of over 1,700 men and women in London
concluded that: “The risk of developing the diseaseincreases in proportion to the amount smoked. It may be
50 times as great among those who smoke 25 or more
cigarettes a day as among non-smokers.”
Before their study, it was unclear whether the rapid rise in
lung cancer was due to smoking or other atmosphericpollution, such as exhaust fumes, industrial plants or tarmac.
Smoking and health: epidemiology
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Smoking and health: epidemiology
Following Doll and Hill‟s research, a large-scale study into the
health and smoking habits of British male doctors began in
1950, continuing with periodic updates until 2001.
Two of the main findings of this British Doctors Study were:
life-long smokers died, on average, 10 years earlier than
non-smokers
the earlier smokers stop smoking, the more chance they
have of avoiding reduced life expectancy.
Which respiratory disease?
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Which respiratory disease?
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Glossary
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Glossary
What’s the keyword?
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What s the keyword?
Multiple-choice quiz