Explain how obesity can increase the risk of developing cardiovascular disease.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Obesity is a growing public health concern in the UK. A person is classified as obese when their body mass index (BMI) exceeds 30. Research shows that obese individuals have a significantly higher risk of developing cardiovascular disease compared to individuals with a normal BMI.
Model answer (4 marks)
Obesity increases body fat, which raises blood volume and cardiac output, leading to high blood pressure (hypertension).
Hypertension damages the inner lining of arteries (endothelium).
Damaged endothelium allows lipids and inflammatory cells to accumulate, forming atheromas (fatty plaques).
Atheromas narrow arteries and can rupture, causing blood clots that block flow and lead to heart attack or stroke.
Hypertension damages the inner lining of arteries (endothelium).
Damaged endothelium allows lipids and inflammatory cells to accumulate, forming atheromas (fatty plaques).
Atheromas narrow arteries and can rupture, causing blood clots that block flow and lead to heart attack or stroke.
Examiner tips
- Use the chain of cause–effect: obesity → hypertension → arterial damage → atheroma → blockage.
- Mention that hypertension is a key risk factor and that atheroma formation is the main mechanism for cardiovascular events.
Common mistakes
- Confusing obesity with diabetes; both are risk factors but the question asks for the direct link via hypertension.
- Omitting the step that atheromas restrict blood flow or that they can rupture and cause clots.
Mark scheme (4 marks)
- Obesity causes high blood pressure (hypertension)
- High blood pressure causes damage to artery walls
- Damaged artery walls lead to the build-up of atheromas (fatty deposits / plaques)
- Atheromas restrict blood flow / increase risk of blockage, leading to heart attack or stroke
Key terms in this question
obesity · cardiovascular disease
Related
- All Edexcel GCSE Biology (1BI0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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