5.3.3 Lifestyle and Non-Communicable Disease · 5. Health, Disease and the Development of Medicines | Edexcel GCSE Combined Science 1SC0: Biology

Section 1 of 9Multiple causes of non-communicable disease

Non-communicable diseases such as cancer, type 2 diabetes, cardiovascular disease and liver disease are usually caused by several factors acting together.

Genetic

Some factors are genetic or due to ageing, but many are lifestyle factors that people can change: diet, activity, smoking, alcohol and drugs.

Environmental factors such as air pollution and exposure to carcinogens also matter.

A risk factor increases the chance of disease but is not a certain cause.

Section 2 of 9Diet, obesity and type 2 diabetes

A diet high in energy and sugar combined with little exercise leads to obesity, usually defined as a body mass index (BMI) above 30, where BMI = mass in kg / (height in m)².

Diet, obesity and type 2 diabetes

For example, a person of mass 90 kg and height 1.70 m has BMI = 90 / 2.89 = 31.

Obesity increases the risk of type 2 diabetes, in which body cells stop responding properly to insulin so blood glucose remains high.

It also increases the risk of cardiovascular disease, some cancers and joint problems.

Regular exercise and a balanced diet reduce the risk.

Section 3 of 9Smoking

Tobacco smoke contains tar (a mixture of carcinogens that cause mutations leading to cancer), nicotine (addictive, increases heart rate and blood pressure), carbon monoxide (binds to haemoglobin and reduces oxygen carried), and particles that damage the lining of the airways.

Smoking

Smoking is linked to lung cancer, chronic bronchitis, emphysema (damage to alveoli) and cardiovascular disease.

Smoking in pregnancy can lower the birth mass of the baby.

Data from large studies in which smokers and non-smokers are compared show a strong correlation, supported by laboratory evidence of how the chemicals cause damage.

Section 4 of 9Alcohol and other substances

Alcohol is broken down by the liver, and heavy drinking can lead to fatty liver, hepatitis and cirrhosis, and damage to the brain and heart.

Alcohol and other substances

It affects reaction time and judgement,

leading to accidents, and drinking in pregnancy can harm the development of the baby.
- (foetal alcohol syndrome)

Some other drugs also have effects on health and on the nervous system.

Section 5 of 9Cancer

Cancer happens when mutations cause cells to divide uncontrollably, forming a tumour.

Benign

A benign tumour stays in one place within a membrane and is not usually dangerous.

Malignant

A malignant tumour invades neighbouring tissues, and cells can spread in the blood and form secondary tumours elsewhere.

Risk factors include smoking, ultraviolet radiation, some viruses, certain chemicals and inherited alleles, for example for breast cancer.

Treatment includes surgery, radiotherapy and chemotherapy.

Section 6 of 9Costs and interpreting data

Non-communicable disease has a high cost to the individual, who may suffer reduced quality of life and income, and to society through health service spending and lost working days.

Costs and interpreting data

When data show deaths from a disease, remember to compare rates per 100 000 people, check whether the sample is large,

and consider other variables such as age, income and diet.

A reliable conclusion needs a plausible mechanism, supporting evidence from many studies and control of confounding factors.

Think also about prevention at population level.

1

Governments use taxes on tobacco and sugary drinks, advertising bans, smoke-free public places, labelling of foods,

and campaigns to encourage exercise.

2

Doctors screen for risk factors, such as measuring blood pressure and cholesterol, and offer advice.

3

Individuals vary in how they respond because genes also affect risk, so two people with the same lifestyle can have different outcomes.

4

Questions often provide a table of rates of disease in different countries or years; describe the pattern first, quote data with units,

then suggest a reason such as diet, wealth, or age of the population.

5

If data come from a survey, comment on the size and representativeness of the sample.

6

Link lifestyle risks to other lessons: smoking and obesity both appear in the cardiovascular disease lesson,

and cancer connects to cell division and mutation.

Exam tip for risk questions

always give a mechanism.
For example, say that saturated fat raises blood cholesterol which builds up in arteries, not just that fat is bad for you.
A mechanism shows biological understanding and is what mark schemes reward.

Section 7 of 9Exam-style questions

A man has a mass of 85 kg and a height of 1.75 m. Calculate his BMI and state whether he is obese. [3]3 marks
Explain how smoking can cause lung cancer. [3]3 marks
Explain why studies showing that smokers have a higher rate of heart disease do not on their own prove that smoking causes it. [2]2 marks

Section 8 of 9Key terms

Term	Meaning
Lifestyle factor	A behaviour such as diet, exercise or smoking that affects health.
Obesity	Excess body fat, with a BMI over 30.
Carcinogen	A substance that can cause cancer.
Tumour	A mass of abnormal cells.
Malignant	A tumour that invades other tissues and can spread.
Benign	A tumour that stays in one place.
Type 2 diabetes	A condition in which body cells do not respond properly to insulin.

Section 9 of 9Exam technique

1

Saying carbon monoxide causes cancer. It reduces oxygen transport; tar is the carcinogen.

2

Treating a risk factor as a guaranteed cause.

3

Confusing benign and malignant tumours.

4

Calculating BMI without squaring the height.