lecture 6: cardiovascular risk factors Flashcards
1
Q
What is cardiovascular (CV) disease?
A
- heart attack
- blockage/atherosclerosis of coronary arteries
- defined in terms of the death of the muscle of the heart
- no collateral arteries that can provide blood when things go wrong
- lots of collateral arteries in the brain
- when heart muscle dies it cannot recover
- stroke
- occurs if there is a problem with blood supply to the brain
- blockage → tissue starved of oxygen
- haemorrhage → blood vessel breaking under pressure and leaking blood into the surrounding tissue
- kills the cells in the brain
- unable to reproduce to make up for what’s lost
2
Q
What are established CVD risk factors?
A
- age
- even leading a healthy life the integrity of blood vessels lessens
- the processes of atherosclerosis are more likely as you get old
- blood pressure
- adding extra stress to vessels and heart
- cholesterol
- higher the level the greater the risk
- contributes to development of athersclerosis
- body mass index
- plugs into BP and cholesterol
- smoking
- diabetes
established risk factors because they have been shown to be associated with cardiovascular disease
3
Q
What are other CVD risk factors?
A
- left ventricular size
- even with no other risk factors people with naturally big hearts had increased risk of dying of CVD
- fibrinogen (clotting factors)
- levels of clotting factors perhaps a predisposition of developing clots
- other lipids
- beyond cholesterols e.g. apoplipoproteins etc
- homocysteine
- losing credibility as a major risk factor
- related to clotting and other factors in a way
- things that are associated with CVD but aren’t established as major risk factors
4
Q
What is true of CVD risk factors?
A
- risk factors tend to aggregate
- weight gain promotes major CVD traits
5
Q
What is the single most important risk factor in CVD?
A
- Age
- 80% of CVD occur in people greater than 65 years
6
Q
What is the relationship between sex and CVD?
A
- men die earlier and more frequently from CVD
- women are “protected” before the menopause
- even after menopause male risk is higher than female
- hormone therapy in the menopause does not reduce CVD
- now limited to the perimenopausal period to help women cope with symptoms e.g. flushes
7
Q
What is the contribution of family history to CVD?
A
- CVD in a first degree relative increases risk 4-fold
- genes and environment
8
Q
Are there CVD genes?
A
- individual genetic variants explain small amounts of risk
- must be polygenic
9
Q
How do lipids contribute to CVD?
A
- cholesterol
- LDL, VLDL – bad cholesterol
- the way the cholesterol is packaged up with proteins
- they are involved with transporting cholesterol and other lipids from the liver out to the peripheral tissues e.g. muscles (good) but sometimes end up in your arteries
- high levels → increased risk of atherosclerosis
- HDL – good cholesterol
- involved in reverse transport of cholesterol
- takes cholesterol from the peripheral tissues back to the liver
- (simplistic)
- marry with the evidence
- increased exercise leads to increased HDL
- also alcohol in moderation
- LDL, VLDL – bad cholesterol
- triacylglycerol
- associated with metabolic syndrome in particular
- tend to go up if your weight goes up
- associated with increased risk but not as strongly as cholesterol
10
Q
What is the contribution of being overweight to CVD?
A
- especially central adiposity
- high BP
- high lipids
- insulin resistance
11
Q
What is the contribution of alcohol to CVD?
A
- two units per day → best amount of alcohol you can drink to lower your risk of CVD
- if you drink with less → higher risk
- drink more → higher risk
- J curve
- HDL cholesterol is one explanation
12
Q
What is the contribution of stress to CVD?
A
- unproven but popular explanation
- paper that linked these was based on the Chicago Heart Study in which type A personalities were implicated but when they actually followed study all the way through it was the type B personalities who died more frequently of CVD
- how do you measure stress?
13
Q
What are graded risk effects?
A
- boxes of varying sizes reflecting the number of people that fit that box
- see that the people with the highest blood pressures have the highest risk
- (y axis is logarithmic, doubling of risks)
- even having a normal blood pressure is associated with a higher risk of CVD than someone who has low blood pressure i.e. even an average blood pressure carries a risk
- bigger jumps in risk with BPs above normal but still an important consideration
- a risk associated with every increment in blood pressure across a community
- relative risk vs absolute risk → a lot more people in the middle boxes, a lot more dying, so actually get more deaths with that particular group
- most of the people who die from CVD as a result of blood pressure are people with relatively average BPs
- concept that it’s all very well for doctors and patients to get together, but the real issue is getting people with even average blood pressure to get theirs lower
- this is the basis of the population public health approach
- medical approach is aimed at finding people with the highest risk and dealing with that individually while the other is aimed at targeting people/large populations with average risk and dealing with that
14
Q
What do public health measures have to be?
A
- safe
- cheap
- effective
- i.e. cannot just be put drugs in the tap water
15
Q
What is the CVD population paradox?
A
- more deaths occur in the large number at modest risk than in the small number at high risk
16
Q
What are approaches to reducing CV disease?
A
- public health prevention
- everybody
- treatment
- patients
17
Q
What are public health approaches to reducing CVD?
A
- better diet
- more exercise
18
Q
What are treatment approaches to reducing CVD?
A
- non-pharmacological
- individualised public health campaign
- fix your diet and exercise
- lifestyle etc
- come back and we will check out cholesterol/BP again etc
- pharmacological
- drugs to treat these things are usually forever
19
Q
When to treat?
A
- when the risk of treatment is less than the benefit of treatment
- take that for granted
20
Q
What is high CV risk?
A
- more than 15% event risk over 5 years (NHF)
- systolic more than 180 mmHg
- diastolic more than 11 mmHg
- systolic greater than 160 mmHg and diastolic less than 70mmHg (reflection of stiffness of vessels)
- but risk isn’t all about blood pressure
- so if systolic is greater than 140mmHg or Diastolic is greater than 90mmHg with associated conditions (diabetes, existing CV or renal disease) or high CV risk
21
Q
What are standard risk factors?
A
- age
- sex
- systolic pressure
- total:HDL cholesterol ratio
- smoking
22
Q
What is end organ damage?
A
- another way to measure risk
- e.g.
- LV hypertrophy
- Low eGFR*
- microalbuminuria *
- pulse wave veolicty
- intima-media thickness
- tests that are starting to appear to measure the overall risk etc
23
Q
How is CVD a modern epidemic?
A
- emerging as a major cause of death in developing countries
- rising in central and Eastern Europe and big asian countries
- falling in North America and Australasia
- falling from low levels in Japan
24
Q
What is the relationship between CVD and society?
A
- important factors
- diet
- cigarette smoking
- others
- diet probably number one: look at japan great diet but lots of smoking
25
Q
What is a possible explanation for low CVD in Japan?
A
- medical care
- low consumer
- smoking
- high (2/3 of men)
- nutrition
- dietary fat is less than 25% of japanese diet (UK 42%)
- PS:S ~ 1.1 (UK 0.4)
26
Q
What is the french paradox?
A
- love pastries, dairy etc
- also love smoking
- what is going on?
- don’t have a japanese diet
- no one knows
- market the concept that it is french red wine
- mysteries about populations are uncertain
