📋 Summary — What This Chapter Covers
- CVD risk factors: lifestyle (diet, blood pressure, smoking) vs uncontrollable factors (genetics, age, biological sex)
- Dietary antioxidants: the vitamin C/heart disease story — a classic example of conflicting evidence
- Core Practical 2: titrating vitamin C against DCPIP to build a calibration curve
- Interpreting data: describing data, drawing conclusions, and judging validity — without falling into the correlation-causation trap
- Designing good studies: sample size, randomisation, controls, repetition, avoiding bias
- Perceived vs actual risk: why people fear flying more than driving, statistically speaking
- Cholesterol & lipoproteins: HDL ("good") vs LDL ("bad") and why the ratio matters more than either alone
- Reducing CVD risk: diet, smoking cessation, exercise — and how public health messaging uses this evidence
- Treatments for CVD: antihypertensives, statins, anticoagulants, platelet inhibitors — their benefits and risks
1. CVD Risk Factors
Cardiovascular disease (CVD) is an umbrella term for anything going wrong with your heart and blood vessels. It's almost always linked to two underlying processes, and it's worth nailing the difference between them because exam questions love testing this:
Two Core Processes
Atherosclerosis — hard fatty plaques (atheromas) build up inside the artery lining, narrowing it and making it stiff.
Thrombosis — a blood clot forms in an artery, often triggered by a ruptured atheroma, which can block blood flow entirely.
Think of atherosclerosis as the slow build-up of gunk narrowing a pipe over years, and thrombosis as the sudden clog that finally blocks it. One sets the scene; the other delivers the crisis (heart attack or stroke).
What exactly is a "risk factor"?
A risk factor is anything statistically linked to a higher chance of developing a disease. Crucially — a risk factor is not a guarantee. A smoker isn't certain to get lung cancer; they just have a much higher probability than a non-smoker. This distinction (risk vs certainty) comes up constantly in exam answers.
Risk factors fall into four broad categories:
| Category | Example |
|---|
| Lifestyle | Diet, smoking, alcohol, exercise |
| Substances in body/environment | Air pollution, asbestos |
| Genetic predisposition | Inherited alleles affecting cholesterol handling |
| Other biological factors | Age, biological sex |
Many diseases arise from the interaction of several risk factors at once — e.g. someone who smokes, eats a high-cholesterol diet, AND doesn't exercise has a much higher combined risk than any single factor would suggest alone. This is why public health advice targets multiple behaviours at once rather than just one.
Lifestyle factors and their mechanisms
| Factor | How it increases CVD risk |
|---|
| Diet high in saturated fat | Raises blood cholesterol → more atheroma formation → more thrombosis risk |
| Diet high in salt | Raises blood pressure |
| High blood pressure |
| Smoking |