Key Stage 4 science · Biology – Health, disease and the development of medicines
GCSE non-communicable disease and new medicines
Not every disease is caught from someone else. At GCSE, students study non-communicable diseases such as cardiovascular disease, type 2 diabetes, lung disease and cancer, and how lifestyle, genes and the environment change the chance of developing them. They also learn how new medicines are discovered, tested in the laboratory and in clinical trials, and checked before they reach patients. The topic is as much about reading evidence carefully as about remembering biology.
Lifestyle disease and medicines, explained
Non-communicable diseases cannot be passed from one person to another. They include coronary heart disease, many cancers, lung diseases such as emphysema, liver disease and type 2 diabetes. Most have several causes working together rather than a single one. A risk factor is something that increases the chance of getting a disease, not a guarantee. Students also learn that not every non-communicable disease is linked to lifestyle: some, such as cystic fibrosis, are inherited, and type 1 diabetes is not caused by diet or lifestyle.
Lifestyle factors matter because they are things people can change. Smoking increases the risk of lung disease, cancer and cardiovascular disease. A diet high in saturated fat and salt, and a lack of physical activity, raise the risk of heart disease and, with obesity, type 2 diabetes. Alcohol damages the liver and, in pregnancy, the unborn baby. Students also meet environmental risk factors such as ultraviolet light, asbestos and ionising radiation, which can cause cancer by damaging DNA. Cancer happens when changes in cells lead to uncontrolled cell division. A benign tumour stays in one place, while a malignant tumour invades neighbouring tissues and can spread through the blood.
Students are also asked to read data critically. Studies often find correlation, where two things change together, such as smoking and lung cancer. Showing that one causes the other needs more: a plausible mechanism, a large sample, and results that hold up when repeated by other scientists. The topic also covers the costs of non-communicable disease to individuals, such as lost earnings and reduced quality of life, and to the health service and the economy.
New medicines come from several routes. Some began with plants and microorganisms, for example aspirin from a chemical in willow, digitalis (a heart drug) from foxgloves and penicillin from a mould. Today most new medicines are made by chemists in the pharmaceutical industry, often by testing very large numbers of compounds, although the starting point may still be a chemical found in a plant. Before any medicine reaches the public, it is tested in laboratory cells and tissues, then in animals where the law requires it, and then in clinical trials. Trials start with healthy volunteers for safety and dose, then involve patients. Good trials use a placebo, are blind or double blind to avoid bias, and are reviewed by other scientists before the results are accepted.
Words your child will hear
- Non-communicable disease
- A disease that cannot be passed from person to person, such as coronary heart disease.
- Risk factor
- Something that increases the chance of developing a disease without making it certain.
- Correlation
- A link in which two things change together. It does not prove that one causes the other.
- Benign and malignant
- A benign tumour stays in one place. A malignant tumour invades nearby tissue and can spread, which is cancer.
- Clinical trial
- A carefully controlled test of a new medicine on people to check it is safe and works.
- Placebo
- A treatment that looks the same as the medicine but has no active ingredient.
- Double blind
- A trial where neither the patients nor the doctors know who is receiving the real medicine.
What the National Curriculum says
The programme of study for Key Stage 4 says:
- Students should be taught about non-communicable diseases
- Students should be taught about the impact of lifestyle factors on the incidence of non-communicable diseases
- Students should be taught about the process of discovery and development of new medicines
Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.
A model exam answer
A company has developed a new drug to lower blood pressure. Describe how it should be tested before it can be given to the public.
- Laboratory testing first. The drug is tested on cells and tissues grown in the laboratory, and on animals where required, to check it is not toxic and to see whether it has the expected effect.
- First human trial. A small group of healthy volunteers is given low doses to check safety and to find the right dose.
- Trial with patients. People who really have high blood pressure are split at random into two groups. One receives the new drug and the other a placebo, so any change can be compared fairly.
- Remove bias. The trial is double blind: neither the patients nor the doctors know who has the real drug until the end, so expectations cannot affect the results.
- Check the results. The data is analysed and reviewed by other scientists before the drug is approved for general use, and side effects continue to be monitored afterwards.
Laboratory tests, then healthy volunteers for safety and dose, then a randomised, double-blind trial with patients using a placebo, then peer review of the results before the drug is approved.
Common mistakes and how to help
“My grandad smoked all his life and was fine, so smoking isn’t that dangerous”
A risk factor raises the chance of disease, it doesn’t guarantee it. One person’s story can feel more convincing than a statistic.
What helps: Talk about populations: among a large group of smokers, many more develop lung disease than among non-smokers. Individual cases are not evidence against the pattern.
Tumour and cancer mean the same thing
The words are used interchangeably in everyday speech, so a lump sounds like a serious diagnosis.
What helps: Benign tumours stay in one place and are not cancer, although a large one can still cause problems by pressing on nearby organs. Malignant tumours invade nearby tissue and can spread, which is what makes a cancer dangerous.
If two things are correlated, one must cause the other
Headlines often use causal words, and a graph with two lines moving together looks convincing.
What helps: Ask: could a third factor explain both? Has the study been repeated? Is there a believable mechanism? Students lose marks for saying “causes” when the data only shows a link.
The placebo group is pointless, or is being left untreated
It seems unfair or wasteful to give some patients a dummy treatment.
What helps: A placebo shows what happens without the active ingredient, because people often feel better when they expect to. Without it, the trial can’t show whether the drug itself made the difference.
How to help at home
- Read a headline together. Find a news story that says a food or habit “causes” or “is linked to” a disease. Ask what sort of evidence it might be, how many people were studied and whether anything else could explain the link.
- Talk habits, not weight. Sleep, movement, family meals and fresh food are positive habits that lower risk. For teenagers, focusing on habits and energy rather than body size avoids unhelpful pressure about appearance.
- Read a food label. Compare the salt, saturated fat and sugar on two similar products from the cupboard. Ask which they would choose and why, then link it to the risk factors on their notes.
- Design a fair trial. Pose a simple question such as whether a new revision method helps, and ask how to test it fairly. Which groups, which measurements, and how would they stop bias? It is the same thinking as a clinical trial.
Related topics
More on biology – Health, disease and the development of medicines
- Key Stage 4: Communicable disease and immunity
Updated .