Aetiology, pathophysiology, definitions, diagnosis and management

Question 1

What are the four non-modifiable risk factors for CVD?

Answer 1

1. Age (primarily affects >50y)
2. Gender (males have higher risk and earlier development)
3. Family history of CVD (shared environment, genetic factors)
4. Ethnic background

Question 2

What are the five modifiable risk factors for CVD?

Answer 2

1. Healthy diet
2. Physical activity
3. Smoking cessation
4. Weight management
5. Alcohol consumption

Question 3

People from which two ethnic backgrounds have an increased risk of CVD compared to Europeans?

Answer 3

1. South Asian
2. Sub-Saharan African

Question 4

People from which two ethnic backgrounds have a decreased risk of CVD compared to Europeans?

Answer 4

1. South American
2. Chinese

Question 5

One in how many deaths in the UK are associated with CVD?

Answer 5

1 in 4

Question 6

Elevated levels of which type of cholesterol are a significant risk factor for CVD?

Answer 6

Low density lipoproteins (LDLs)

Question 7

What are the four major sources of dietary cholesterol?

Answer 7

1. Eggs
2. Offal
3. Dairy foods
4. Shellfish

Question 8

What typically contributes more to body cholesterol: bile or ingested cholesterol?

Answer 8

Bile at approx 1000mg/day, compared to 3-400mg in a typical westernised diet

Question 9

Is cholesterol absorption standard or varied between individuals?

Answer 9

Varied between approx 29-80%

Question 10

What factors are believed to affect cholesterol absorption?

Answer 10

Receptors in enterocytes called NPC1L1 receptors whose activity is affected by genetic variations

Question 11

What three homeostatic controls exist for cholesterol levels in the body?

Answer 11

1. Endogenous synthesis
2. Intestinal absorption
3. Hepatic excretion

Question 12

Increased cholesterol intake enhances gut absorption.
In what four ways does the liver respond to prevent lipotoxicity?

Answer 12

1. Reducing cholesterol synthesis
2. Downregulates NPC1L1 receptor to reduce absorption
3. Increases HPB excretion of cholesterol in to bile
4. Reduces LDL receptor expression to reduce LDL uptake by the liver

Question 13

What are three major sources of saturated fat in the diet?

Answer 13

1. Meat
2. Dairy products e.g. ghee, butter, cheese, milk
3. Some vegetable oils e.g. coconut, palm, cocoa butter
4. Lard

Question 14

How does saturated fat increase LDL cholesterol levels

Answer 14

1. Inhibits activity of hepatic LDL receptors which increases circulating levels
2. Upregulates synthesis of LDL particles

Question 15

Is the effect of saturated fat intake on LDL levels standard or varied between individuals?

Answer 15

Varied

Question 16

What are three potential mechanisms causing inter-individual variation in LDL response to saturated fat?

Answer 16

1. Genetics e.g. apolipoprotein E phenotype
2. Bile acid composition
3. Gut microbiota composition

Question 17

Why were cholesterol limits abandoned for the general population?

Answer 17

Dietary cholesterol has a relatively small effect on serum LDL and CVD risk compared to other diet and lifestyle factors

Question 18

Which two groups are still advised limits on cholesterol and what are their limits?

Answer 18

1. Those with or at high risk of developing CVD - <300mg/day
2. Familial hypercholesterolaemia/hyperabsorbers - <200mg/day