B7: Non-communicable diseases

Communicable diseases

• Can spread from person to person

• Spread by a pathogen

Non-communicable disease

Can’t be passed from person to person

Health

State of physical + mental well being

What are non-communicable diseases caused by?

Risk factors

Edpidemiology

Study of the patterns of disease to determine its risk factors

How can different types of disease may interact?

• 4

1. Defects in IS → individual more likely to suffer from infectious diseases

2. Viruses living in cells trigger cancers

3. Immune reactions initially caused by a pathogen trigger allergies eg skin rashes + asthma

4. Severe physical ill health can lead to depression + other mental illness

Risk factors

Factors linked to an increased rate of a disease

What are many diseases caused by?

Interaction of a number of factors

What can risk factors be?

1. Aspects of a person’s lifestyle

2. Substances in the person’s body or environment

Correlation

A link between two factors

• Eg non-communicable disease + lifestyle factors

How to determine if there is a correlation between 2 factors?

Plot scatter graph

Positive correlation

When 2 variables move in the same direction

• As 1 increases, the other also increases

Correlation doesn’t prove…

Cause

What does this graph show?

Suggests smoking cigarettes + lung cancer linked

• Doesn’t prove smoking causes lung cancer

Causal mechanism

Scientific explanation of how 1 factor causes another thru a biological process

Causal mechanism of how cigarette smoking causes cancer

Cigarette smoke contains chemicals that damage DNA + increase risk of cancer

Carcinogen

Cancer causing chemical

When will scientists accept that 1 factor increases the risk of another factor?

• Strong correlation betw 2 factors

• Causal mechanism proved

Has a causal mechanism been proven for all risk factors?

No- only some

Issue with studying patterns of disease to determine risk factors?

Sampling- not possible to sample every single person

Ideally how would you investigate if a disease is linked to diet?

1. Look at every single person in population

2. Look at what they ate + chances of them developing the disease

What do scientists do instead of sampling every single person in the population?

• Sample a group of people

• Then try to draw conclusions abt the whole population

Issue with sampling

Can get biased sample → can’t use results to draw conclusions abt whole country

Example of biased sample

Sample selected from only 1 town → may not represent entire pop of country

• Eg ppl in the town may do less exercise than average or be exposed to certain type of pollution only there in that town

How to avoid bias when sampling?

• Use large sample

• Must be as random as possible

What can’t conclusions be drawn from?

Small / non-random sample

What do scientists need to prove a correlation?

Causal mechanism

Is the human and financial cost of non communicable diseases high or low?

High

Human cost of non communicable diseases (individual, local community)

Lots of people die per year from NCD:

1. Individual- emotional

2. Financial effect on family / local community (support people who are ill)

Financial effects of NCDs on nations

Expensive to:

• Treat ill people

• Research into disease

Financial effects of NCDs globally

Disease affects working age population

What happens in cell division by mitosis?

1 cell copied into 2 identical cells

Where does cell division by mitosis in the body occur?

All over the body

When are rates of mitosis high in the body?

During growth + repair

Key feature of mitosis

Tightly controlled process

How is mitosis a tightly controlled process?

Genes in nucleus tell cells when to divide + when to stop dividing

What do changes in genes (that control mitosis) lead to?

Uncontrolled growth + mitosis

What produces a tumour?

Uncontrolled growth + mitosis

Tumour

Mass of abnormally growing cells formed when control in cell cycle is lost

2 types of tumor

• Benign

• Malignant

Benign tumors

Growths of abnormal cells contained in 1 area, within a membrane

Features of benign tumours

Don’t invade other parts of the body

Are benign tumors cancerous?

No

When can benign tumors be dangerous?

When it causes pressure / damage to an organ

Malignant tumour cells

Cancers

Malignant tumours

Mass of abnormal cells that invade neighbouring tissues + move into BS

Features of malignant tumours (cells)

Once in BS, MC spread to diff parts of body + form secondary tumours

How are secondary tumours formed?

1. MC invade neighbouring tissue + move into BS

2. MC spread to diff parts of body → undergo uncontrolled cell division → forms ST

How are cancer cells different to normal cells?

• Divide quicker

• Live longer

What is cancer the result of?

1. Changes in the DNA of cells (mutations)

2. That lead to uncontrolled growth + division

3. Results in the formation of a malignant tumour

Cancer

Result of mutations in cells, leading to uncontrolled growth + division, forms MT

Risk factors for developing cancer

1. Genetics- (breast, prostate, LI)

2. Lifestyle (eg substances in enviorment)

What does it mean if the risk factor for cancer is genetic?

Can inherit genes from our parents that increase the risk of these cancers

Cancers linked to lifestyle

1. Smoking → lung

2. Ultraviolet → skin

3. Alcohol → mouth + throat

What substances in the environment can cause cancer?

Radon → lung cancer

Radon

• Radioactive gas

• Increases risk of developing lung cancer

How does radon increase the risk of lung cancer?

• Releases ionising radiation, which damages DNA in cells

• Causes uncontrolled cell division in cells → cancer

Example lifestyle factors that can increase risk of NCD

• Diet

• Alcohol

• Smoking

Risk factors for cardiovascular diseases

1. Diet

2. Smoking

How does a high fat diet increase risk of cardiovascular disease?

↑ cholesterol level in blood → ↑ rate fatty materials build up in arteries

How does a diet high in salt increase risk of cardiovascular disease?

↑ blood pressure

What decreases risk of developing cardiovascular diseases?

Regular exercise

What does smoking increase the risk of?

• Lung cancer

• Lung diseases (emphysema)

• Miscarriage

How does smoking increase the risk of lung cancer?

Cigarette smoke contains carcinogens

Carcinogens

Chemicals that can trigger cancer

Effects of NCD

• Poor life quality

• Reduced life span

Effects of smoking when pregnant on unborn baby?

↑ risk of

• Miscarriage

• Premature birth

• Baby born w low body mass

After smoking, why do you feel breathless?

CO binds to haemoglobin instead of O2

How does smoking increase risk of infections?

1. Cilia move mucus + bacteria away from lungs

2. Chemicals in smoke paralyzes cilia in trachea + bronchi

3. So pathogens enter the lung

What does smoking do to blood vessels?

Narrows it

What does drinking alcohol while pregnant cause?

Fetal alcohol syndrome

What do children born with FAS have?

• Learning difficulties

• Mental + physical problems

Pregnant women shouldn’t

• Drink alcohol

• Smoke

Example carcinogens

1. Ionising radiation

2. Tar (in smoke)

3. Alcohol

What does drinking alcohol increase the risk of?

1. Fetal alcohol syndrome

2. Liver cirrhosis

3. Liver cancer

4. Memory loss

What organ can alcohol affect?

1. Liver

2. Brain → leads to addiction + memory loss

What can’t people with type 2 diabetes control?

Their blood glucose levels

What can type 2 diabetes lead to?

Blindness

What may type 2 diabetes require?

Amputation of limb

Risk factor for type 2 diabetes?

Obesity

Risk factors interacting: how does drinking alcohol increase risk of type 2 diabetes?

Drink excess alc → obesity (increase risk of T2D)

What happens if you eat more food than you need?

Excess stored as fat

What does the food you eat transfer?

Energy to muscles

What does the amount of exercise you do affect?

• Amt of respiration in muscles

• Hence amt of food you need