CB5.4 — Non-communicable disease (Edexcel 1SC0)
Cardiovascular disease (CVD)
CVD is the leading cause of death in the UK. Main forms: coronary heart disease (CHD), stroke.
Mechanism of CHD:
- Atherosclerosis: fatty plaques (cholesterol + other substances) build up in artery walls.
- Lumen narrows → reduced blood flow → reduced oxygen delivery to heart muscle.
- Blood clot (thrombosis) may form on rough plaque surface.
- Blockage → heart attack (myocardial infarction) or stroke.
Lifestyle risk factors
| Risk factor | How it increases CVD risk |
|---|---|
| High cholesterol diet | More cholesterol available for plaque formation |
| Obesity (high BMI) | Raised blood pressure; increased cholesterol |
| Smoking | Nicotine raises heart rate; carbon monoxide reduces O₂ in blood; damages artery walls |
| Lack of exercise | Reduces HDL cholesterol; increases blood pressure |
| Excessive alcohol | Raises blood pressure; increases triglycerides |
| Stress | Raises blood pressure; may lead to unhealthy behaviours |
BMI
$$\text{BMI} = \frac{\text{mass (kg)}}{\text{height}^2 \text{ (m}^2\text{)}}$$
BMI 18.5–24.9 = healthy; 25–29.9 = overweight; ≥30 = obese.
Treatments
- Statins: lower blood cholesterol.
- Anticoagulants: reduce blood clotting (e.g. warfarin).
- Stents: metal mesh inserted to keep artery open.
- Bypass surgery: healthy vessel used to route blood around a blocked coronary artery.
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