What are non-communicable diseases, and how are new medicines developed and tested?
Non-communicable diseases and their risk factors, the effect of lifestyle on health, the development and testing of new drugs, and the stages of clinical trials.
A focused answer to Edexcel GCSE Combined Science Topic 5 (CB5), covering non-communicable diseases and their risk factors, the effect of lifestyle on health, how new drugs are discovered and developed, and the stages of preclinical and clinical testing.
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What this dot point is asking
Edexcel wants you to describe non-communicable diseases and their risk factors, explain how lifestyle affects health, and describe how new drugs are discovered, developed and tested through preclinical and clinical trials.
Non-communicable diseases
Risk factors
A risk factor is anything that increases the chance of developing a disease. Important ones include:
- Smoking - linked to lung cancer and cardiovascular disease.
- Poor diet (high in fat or sugar) - linked to obesity, type 2 diabetes and heart disease.
- Lack of exercise - linked to obesity and heart disease.
- Alcohol - linked to liver disease and some cancers.
Some risk factors interact: being overweight, for example, both raises blood pressure and makes type 2 diabetes more likely, so the effects can add up. Risk factors may be part of a person's lifestyle (such as diet, exercise, smoking and alcohol), which can be changed, or they may be things a person cannot control, such as their age or inherited genes. Public-health campaigns often target the lifestyle factors because changing them can lower the rate of disease across a whole population.
Developing new medicines
New drugs must be shown to be safe (low toxicity), effective (they work), stable (can be stored), and able to be taken into and removed from the body. They are tested in stages.
Preclinical testing
The drug is first tested on cells and tissues in the laboratory, then on animals. This checks for toxicity, whether the drug works, and a suitable dose, before any human is involved.
Clinical testing
If preclinical tests are passed, the drug enters clinical trials:
- Tested on a small number of healthy volunteers at very low doses to check safety and side effects.
- Tested on a small number of patients to find the best dose and check it works.
- Tested on large numbers of patients to test how effective it is.
Trials often use a placebo (a dummy treatment) and a double-blind design, where neither the patient nor the doctor knows who has the real drug, to avoid bias. Results are checked by other scientists (peer review) before the drug is approved.
Try this
Q1. Define a risk factor. [1 mark]
- Cue. Something that increases the chance (probability) of developing a disease.
Q2. State what is tested in preclinical trials. [1 mark]
- Cue. Toxicity, whether the drug works, and dose, using cells, tissues and animals.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20204 marksA study finds that people who smoke are more likely to develop lung cancer. Explain what is meant by a risk factor, and why this correlation does not on its own prove that smoking causes lung cancer.Show worked answer →
A 4-mark question on risk factors and correlation versus cause.
A risk factor is something that increases the chance (probability) of developing a disease (1 mark). A correlation means two things are linked, here smoking and lung cancer occurring together, but on its own it does not prove cause, because a third factor could be responsible, or the link could be coincidence (2 marks). To show cause, scientists need a plausible mechanism (for example chemicals in smoke damaging lung cells) and repeated, controlled studies (1 mark).
Markers reward defining a risk factor as increasing probability, explaining why correlation is not proof, and how cause is established.
Edexcel 20225 marksDescribe the main stages a new drug goes through, from discovery to being prescribed, and state what is tested at each stage.Show worked answer →
A 5-mark describe question on drug development.
First the drug is tested in preclinical trials on cells and tissues, then on animals, to check it works and for toxicity (2 marks). If it passes, it goes to clinical trials on healthy volunteers using very low doses to test for safety and side effects (1 mark). Then it is tested on a small number of patients, and the dose is optimised (1 mark). Larger clinical trials on many patients, often using a placebo and a double-blind design, test how well it works before it can be approved and prescribed (1 mark).
Markers reward the order: preclinical (cells, tissues, animals) then clinical (healthy volunteers, then patients), with safety, efficacy, dose and side effects tested.
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Sources & how we know this
- Edexcel GCSE (9-1) Combined Science (1SC0) specification — Pearson (2016)