Causes of non-communicable diseasesSpec 5.23
Many non-communicable diseases are caused by the interaction of a number of factors. No single factor usually explains why one person gets the disease and another does not.
| Type of disease | Examples of factors involved |
|---|---|
| Cardiovascular disease | Diet, lack of exercise, smoking, alcohol, inherited factors |
| Many forms of cancer | Smoking, harmful radiation, certain chemicals, inherited factors |
| Some lung diseases | Smoking, air pollution |
| Some liver diseases | Drinking too much alcohol |
| Diseases influenced by nutrition | Too much or too little of certain foods; obesity and malnutrition |
Factors can be lifestyle (what a person chooses to do), environmental (what a person is exposed to) or inherited (passed on in genes). Having several of these together increases the chance of disease more than having one alone.
Lifestyle factors and non-communicable diseasesSpec 5.24
Lifestyle choices affect the risk of non-communicable diseases. Their effects are seen at three levels.
| Level | What it means | Example |
|---|---|---|
| Local | A community, town or region | Local access to affordable healthy food and sports facilities affects obesity rates |
| National | A whole country | The cost to a country's health service of treating cardiovascular disease; government campaigns |
| Global | Around the world | Obesity and malnutrition are both found around the world; the WHO monitors and responds to them |
Exercise and diet: obesity and malnutrition
Malnutrition is a diet that does not contain the right balance of nutrients. It can mean too little food or too much. Obesity is having too much body fat, often because energy taken in from food is greater than energy used in exercise. Obesity increases the risk of cardiovascular disease and other diseases influenced by nutrition. Regular exercise and a balanced diet reduce the risk.
Two measurements are used to assess body size:
A high BMI suggests a person is overweight or obese. A high waist : hip ratio means more fat is stored around the waist, which is linked to a higher risk of cardiovascular disease. You will be given the values to compare with.
Calculating BMI
A person has a mass of 72 kg and a height of 1.80 m. Calculate their BMI.
- height² = 1.80 × 1.80 = 3.24 m²
- BMI = mass ÷ height² = 72 ÷ 3.24
- BMI = 22.2
Answer: BMI = 22.2 (to 1 decimal place)
Calculating waist : hip ratio
A woman has a waist circumference of 81 cm and a hip circumference of 90 cm. Calculate her waist : hip ratio.
- waist : hip ratio = waist circumference ÷ hip circumference
- = 81 ÷ 90
- = 0.90
Answer: 0.90 (a ratio has no units, as long as both measurements are in the same unit)
Alcohol and liver disease
The liver breaks down alcohol. Drinking too much over a long time damages liver cells and can cause liver diseases such as a fatty liver, inflammation and scarring (cirrhosis), which can lead to liver failure.
Smoking and cardiovascular disease
Chemicals in tobacco smoke damage the lining of arteries, which increases the build-up of fatty deposits and narrows the arteries. Nicotine also increases heart rate and blood pressure. Together this increases the risk of cardiovascular disease. Smoking is also a risk factor for lung diseases and lung cancer.
Treating cardiovascular diseaseSpec 5.25
Cardiovascular disease is disease of the heart or blood vessels. In an evaluate question you must give advantages and disadvantages of each treatment, then reach a conclusion.
| Treatment | Advantages | Disadvantages |
|---|---|---|
| Life-long medication, for example statins to lower cholesterol, or drugs that lower blood pressure or stop blood clotting | Reduces risk; no operation needed; can be effective for many years | Must be taken every day for life; possible side effects; ongoing cost; may be forgotten |
| Surgical procedures, for example stents, bypass surgery, valve replacement or a heart transplant | Can quickly restore blood flow or heart function; effective for serious cases | Risks of surgery such as infection and bleeding; recovery time; cost; a transplant needs a donor and may be rejected |
| Lifestyle changes, such as stopping smoking, eating a balanced diet and exercising | Cheap; no side effects; also reduces the risk of other diseases | Needs long-term effort; results take time; not enough alone for severe disease |
The best choice depends on the patient. Lifestyle changes are suitable for most people to reduce risk. Medication is used to manage existing disease. Surgery is usually used when disease is severe or has caused a blockage.
Quick check
What does it mean that many non-communicable diseases are caused by an interaction of factors?
Show answer
Several factors, such as lifestyle, environmental and inherited factors, act together to cause the disease, rather than one factor alone.
Write the BMI equation.
Show answer
BMI = mass (kg) ÷ height (m)²
How does smoking increase the risk of cardiovascular disease?
Show answer
It damages artery linings, so fatty deposits build up and arteries narrow; nicotine raises heart rate and blood pressure.
Which disease is linked to drinking too much alcohol?
Show answer
Liver disease, for example cirrhosis.
Give one advantage and one disadvantage of life-long medication.
Show answer
It reduces risk without surgery; it must be taken for life and may have side effects.