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A risk factor is a factor that increases the likelihood of developing a disease. Free GCSE Edexcel Biology notes with key definitions and 13 FAQs.
Risk Factors and Lifestyle Effects on Health (Part 1/2) is part of Animal tissues, organs and organ systems in GCSE Edexcel Higher Biology.
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A risk factor is a factor that increases the likelihood of developing a disease. Free GCSE Edexcel Biology notes with key definitions and 13 FAQs.
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Use this lesson to stay inside Animal tissues, organs and organ systems while connecting the detail back to the wider Topic 5: Health, disease and the development of medicines topic.
Read the core explanations from Risk Factors and Lifestyle Effects on Health (Part 1/2) before testing yourself from memory.
Your health isn't just about luck. Every day, you make choices that either protect your body or put it at risk. Some people smoke for decades and never get lung cancer. Others eat junk food daily but stay slim. Why the difference?
Think of risk factors like loading dice. One loaded die might still roll a six, but load enough dice and you're almost certain to lose. Risk factors work the same way - they increase your chances of disease.
Risk factors fall into two main categories: aspects of your lifestyle (what you choose to do) and substances in your body or environment (what you're exposed to). Let's see how this plays out in real diseases.
Your heart is a muscle that beats 100,000 times per day. Like any hardworking muscle, it needs the right fuel and regular maintenance. Get this wrong, and cardiovascular disease becomes much more likely.
Diet effects: A diet high in saturated fats and salt increases blood pressure and cholesterol levels. This damages artery walls and makes blood clots more likely. Think of your arteries like pipes - fatty deposits narrow them, forcing your heart to pump harder.
Exercise effects: Regular exercise strengthens your heart muscle, lowers blood pressure, and improves cholesterol balance. It also helps maintain a healthy weight, reducing strain on your cardiovascular system.
Smoking effects: Tobacco smoke contains over 70 carcinogens and damages blood vessel walls. Nicotine increases heart rate and blood pressure, while carbon monoxide reduces oxygen transport. This triple threat massively increases cardiovascular disease risk.
Here's a connection that catches many students off-guard: being overweight doesn't just affect how you look - it fundamentally changes how your body processes sugar.
In Type 2 diabetes, your body becomes resistant to insulin - the hormone that moves glucose from blood into cells. Obesity makes this worse because fat tissue, especially around the abdomen, releases chemicals that interfere with insulin action.
The vicious cycle: Obesity → insulin resistance → high blood glucose → more fat storage → worse insulin resistance. Breaking this cycle requires lifestyle changes: better diet, more exercise, and often weight loss.
Alcohol affects two crucial organs differently, and understanding both helps explain why drinking guidelines exist.
Liver damage: Your liver breaks down alcohol, but this process produces toxic chemicals. Heavy drinking overwhelms the liver's repair systems, leading to fatty liver, hepatitis, and eventually cirrhosis (scarring that can't be reversed).
Brain effects: Alcohol is a depressant that slows brain activity. Short-term: impaired judgment, slower reactions, memory problems. Long-term: permanent brain damage, addiction, and increased risk of mental health problems.
Effects on unborn babies: Alcohol crosses the placenta freely. Even small amounts can cause fetal alcohol syndrome - permanent brain damage, growth problems, and facial abnormalities. No amount of alcohol is safe during pregnancy.
Tobacco smoke isn't just one harmful substance - it's a cocktail of over 4,000 chemicals, including more than 70 known carcinogens. Here's how this chemical assault damages your body.
Lung disease: Smoke particles irritate and inflame lung tissue. Over time, this destroys the tiny air sacs (alveoli) where gas exchange happens, leading to emphysema and chronic bronchitis - collectively called COPD.
Cancer development: Carcinogens damage DNA in cells. Usually, damaged cells die or repair themselves. But if DNA repair fails, cells can become cancerous - growing uncontrollably and spreading to other organs.
Effects on pregnancy: Smoking during pregnancy reduces oxygen supply to the fetus, increases miscarriage risk, and causes low birth weight. Carbon monoxide from cigarettes binds to hemoglobin more strongly than oxygen, literally suffocating the developing baby.
Risk factor questions appear frequently in GCSE exams, often worth 4-6 marks. Here's how to maximise your score.
Worked example: Worked Example: Applying Risk Factors and Lifestyle Effects on Health (Part 1/2)
Use this method to answer an exam-style question about what are risk factors?.
Answer: A complete response links mechanism, evidence, and conclusion for risk factors and lifestyle effects on health (part 1/2).
Command word focus: 'Describe' questions want you to state what happens. 'Explain' questions need the biological reason why it happens. 'Evaluate' questions require you to weigh up evidence and reach a conclusion about the relative importance of different risk factors.
Remember: examiners often test your understanding that correlation doesn't equal causation. Just because two things happen together doesn't mean one causes the other - there might be other factors involved.
Published by Revise Right. Use the official specification reference to check the requirements for your course. Content updated: 2026-03-23.
Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.
COPD is the collective name for emphysema and chronic bronchitis. Smoke particles irritate and inflame lung tissue, and over time this destroys the alveoli, the tiny air sacs where gas exchange happens.
Insulin resistance is when the body becomes resistant to insulin, the hormone that moves glucose from blood into cells. It happens in Type 2 diabetes and is made worse by obesity, because fat tissue around the abdomen releases chemicals that interfere with insulin action.
Cirrhosis is scarring of the liver that cannot be reversed, caused by heavy drinking. Breaking down alcohol produces toxic chemicals, and heavy drinking overwhelms the liver's repair systems, leading to fatty liver, hepatitis and eventually cirrhosis.
Risk factors for cardiovascular disease include a diet high in saturated fats and salt, which raises blood pressure and cholesterol, lack of exercise, and smoking. Nicotine increases heart rate and blood pressure, while carbon monoxide reduces oxygen transport.
A risk factor is a factor that increases the likelihood of developing a disease. Risk factors do not guarantee disease but stack the odds against a person, and they fall into two categories: aspects of lifestyle and substances in the body or environment.
Smoking during pregnancy reduces oxygen supply to the fetus, increases miscarriage risk and causes low birth weight. Carbon monoxide from cigarettes binds to hemoglobin more strongly than oxygen, literally suffocating the developing baby.
Examples of carcinogens include chemicals in tobacco smoke, asbestos and ionising radiation. A carcinogen is a substance that can cause cancer by damaging DNA in cells, and tobacco smoke contains more than 70 known carcinogens.
Smoking affects the heart because tobacco smoke damages blood vessel walls, nicotine increases heart rate and blood pressure, and carbon monoxide reduces oxygen transport. This triple threat massively increases cardiovascular disease risk.
Obesity is a risk factor for Type 2 diabetes because fat tissue, especially around the abdomen, releases chemicals that interfere with insulin action, so the body becomes resistant to insulin. The result is a vicious cycle of insulin resistance, high blood glucose and more fat storage.
The liver breaks down alcohol, but this produces toxic chemicals, so heavy drinking leads to fatty liver, hepatitis and eventually cirrhosis. Alcohol is a depressant that slows brain activity, causing impaired judgment and slower reactions, and long-term permanent brain damage and addiction.
Regular exercise reduces the risk of heart disease because it strengthens the heart muscle, lowers blood pressure and improves cholesterol balance. It also helps maintain a healthy weight, reducing strain on the cardiovascular system.
Fetal alcohol syndrome is permanent brain damage, growth problems and facial abnormalities in a baby caused by alcohol during pregnancy. Alcohol crosses the placenta freely, and no amount of alcohol is safe during pregnancy.
A diet high in saturated fats and salt increases blood pressure and cholesterol levels, which damages artery walls and makes blood clots more likely. Fatty deposits narrow the arteries, forcing the heart to pump harder.