Risk factors for Atherosclerosis and principles of primary and secondary prevention Flashcards
(34 cards)
Contributions of INTERHEART study
- identifies/confirms risk factors
- identified daily consumption of fruits and vegetables, regular physical activity and regular alcohol intake as protective
- study across genders and ethnic races, and different ages
What did interheart conclude about risk factors
That known moifiable risk factors account for 90% of the population attributable risk in men and 94% in women for mi
Non modifiable risk factors for atherosclerosis
1) Age
2) Gender
3) Genetic predisposition (as indicated by family hx)
Age as a risk factor
-over a lifetime individuals bv are exposed to a variety of fators that damage the endothelium –> initiating inflammatory process that leads to formation of atherosclerotic plaques over time
Gender as a risk factor
- men have earlier onset of CHD
- difference probably due to protective effects of estrogen on bv wall and endothelium (protective effect lost at menopause)
In what type of premenaupausal women is the protective effect of estrogen lost
-mainly if they are diabetic and to lesser extent if they -smoke -genetic dyslipidemia ** although protective effect is reduced
What can early vascular disease in men be attributed to
1) Lack of estrogen
2) lower HDL-C
3) Increased abdominal (visceral) fat
Family history of vascular disease
1) early onset in first degree male (father, brother or son) before age 55 or female (mother sister or duaghter) before 65
Genetic predictors of heart disease (that are inherited in some)
- elevated LDL cholesterol
- low HDL cholesterol
- high bp
- diabetes
- elevated lipoprotein a
Modifiable risk factors for atherosclerosis
- diet
- exercise
- elevated LDL-C
- low HDL-C
- smoking
- stress
- hypertension
- abdominal obesity
- inflammation
Dietary factors increasing risk atherosclerosis
-both indirect and direct increase risk atherosclerosis
Direct:
-trans and sat fats and high cholesterol in diet –> directly cause endothelial damage and plaque development
Indirect:
-calorie excess –> weight gain, abdominal obesity and hypertension related to weight gain
-diabetes
Dietary factors reducing risk coronary events
-higher levels of fruit/vegetable intake
Sedentary lifestyle as risk factor
-being sedentary = predictor of increased risk of vascular events (heart attack, stroke, tia, coronary bypass surgery, death due to mi)
Benefits of exercise
- reduced bp
- reduced LDL_C
- reduced triglycerides
- reduced progression of impaired glucose tolerance to type 2 diabetes mellitus
- increased HLD-C
- improved heart function
- *benefits even in absence of weight loss
Harmful role of lipoproteins including LDL
- elevated LDL particles (also indicated by elevated LDL and apolipprtein B)
- accumulate in artery wall and taken up either as aggregated LDL or oxidized LDL by macrophages or smooth muscle cells in the artery
- leads to foam cell formation and atherosclerotic lesions (plaques)
LDL and other risk factors
In the presence of other risk factors that damage the bv endothelium even lower levels of LDL can pass through the endothelium more easily and accumulate and cause harm
triglycerides as risk factor
- increased triglycerides on LDL make LDL more likely to be digested to smaller and denser particle
- making LDL more hamful
i. e. high triglycerides can be atherogenic if LDL or apoB levels are also elevated
HDL and apolipoprotein A-I
-HDL and its main protein component apoA-I correlate with protection against heart disease
Potential protective actions of HDL
-ability to remove excess cholesterol delivered to arterial cels by LDL (reverse cholesterol transport) and to induce relaxation of the artery wall
Strongest modifiable predictor of risk for mi as identified in INTERHEART
the ratio of apoB/apoA-I
-highlights the importance of the balance between delivery of cholesterol into the arteries by LDL and its removal by HDL
Assessment of someones cholesterol profile
-determine whether high cholesterol due to environmental factors (diet & exercise) or is genetic
Cholesterol levels likely due to genetic factors
- total cholesterol levels > 6.5 mmol/l
- or HDL < 0.7 mmol/l
- or LDL > 4.5 mmol/l
- or triglycerides >3 mmol/l
Why smoking is a risk factor for atherosclerosis + benefit of quitting
- inhaled chemicals dissolve in blood and damage endothelium
- damage leads to constriction of bv and reduction of flow to tissue including the heart
- harm is reduced immediately upon stopping smoking and long term risk mainly gone after 2 years of quitting
Why physochological stress is a risk factor for atherosclerosis
-something to do with stress resulting in increased blood cortisol and adrenaline levels and increased inflammatory cytokine levels and damage to the blood vessel endothelium
