PPS: Risk Factors, Health Models, Management and Prevention of CHD Flashcards

Question

Why do we not want zero cholesterol?

Answer 1

Some necessary for cell membrane structure, etc. Keep LDL less than 2

Answer 2

An independent risk factor for CVD Abdominal obesity associated with the Metabolic Syndrome which also includes: –dyslipidaemia –hypertension –insulin resistance

Answer 3

Death from ischaemic heart disease and stroke

Answer 4

No previous CVD event | Risk assessment

Answer 5

Known CVD event (coronary heart disease, peripheral vascular disease, stroke) Proven to be high risk

Answer 6

For social scientists, ‘risk’ is most simply defined as the probability of a bad outcome occurring in relation to some event or behaviour. ‘Risk’ is understood to be a social construct (see next slide). That is, it does not exist in some objective space as an unchangeable feature of the physical world. Hence, the existence of quite different perceptions of what constitutes a health risk held by the public and by health professions.

Answer 7

The understanding that everyday knowledge is creatively produced by individuals and is directed towards practical problems. That is, we to come to know our world through the ideas and beliefs we hold about it - So that it is our shared concepts and categories that become our realities of the world. ‘Social facts’ are therefore created through interactions and mutual interpretations. Social constructions vary cross- culturally

Answer 8

Assessments of ‘risk’ are routinely practised not only within medicine, but also within engineering, finance, and many other sectors. This approach has shaped disease prevention strategies in UK. The assessment process sees the measurement of risk as being a technical matter, with “hard” quantitative analysis seen as being able to identify relative risk (i.e risk of disease, bridges falling down, stock market crashes, etc).

Answer 9

Linking identifiable 'risks' (volitional health behaviours like excessive drinking or unprotected sex) linking directly with actual or potential harm such as disease onset

Answer 10

In health prevention strategies, the assessment process seeks to link identifiable ‘risks’ (usually conceived as volitional health behaviours) directly with actual or potential harm i.e disease onset. A ‘health risk’ is therefore constructed through the process of aggregating statistical probabilities of a particular set of actions, linked to disease outcomes across whole populations. This epidemiological approach is then able to identify particular ‘at risk’ groups i.e smokers, the obese, sexually active teenagers, ‘heavy’ drinkers, etc, who then become the traditional target of health promotion interventions

Answer 11

In order to decide what is the level of health ‘risk’ associated with a given set of behaviours and events, epidemiologists are required to make a host of assumptions about the combinations of behaviours, and the context in which such activity arises. The kind of imagination they then bring to this activity depends on their objectives, values, training, and experience (Jasanoff).

Answer 12

In essence, epidemiology transforms what are statistical relationships existing between a range of population health variables, into causal factors for individual and social group health outcomes. These statistically-generated risk factors then become constructed as realities in their own right. Although in practice, most epidemiologists do acknowledge that health risk is not primarily volitional in character.

Answer 13

An exclusive focus on individual health risk can end up neglecting the less easily measurable social and cultural contexts within which these risky’ behaviours occur. It is environmental factors beyond the control of individuals that often determine relative ‘risk exposure’ – the place where you live, what your job is, the type of housing you live in, etc. Yet as Sheila Jasanoff has stated (with irony): ‘There is a pervasive view that “hard” analysis represents risks as they “really are”, whereas “softer” work in politics or sociology mostly explains why people refuse to accept the pictures of reality that technical experts produce for them with considerable investment of human ingenuity’ .

Answer 14

Theories of health risk can be broadly separated into two types of social analysis, micro and macro. The socio-cultural context in which lay people try and make sense of ‘expert’ risk assessments. The wider social and environmental context in which the hazards and insecurities of modern industrialised societies occur.

Answer 15

This approach emphases the cultural relativity of the notion of risk. Individual and social group understanding of health risk are seen to a culturally variable product, deriving from a shared social value system. A shared culture represents the attempt to make social relations meaningful and predictable for individuals – as such it acts as a bulwark against the inevitable uncertainties and anxieties of social life.

Answer 16

The challenge in constructing preventative healthcare strategies is to be able to translate the numbers and measurements derived from medico-epidemiological research, into culturally meaningful knowledge. Social research have shown that lay people tend to transform numbers and degrees into simple all-or-nothing messages: Measurements and results expressed as numbers seem to be strong metaphors which people contextualize and interpret in different ways according to their personal experience and spheres of knowledge (Adelswärd & Sachs 1996).

Answer 17

Social and anthropological research has found that what might be regarded as ‘risky’ (health) behaviour, often operates at a latent, or extra-rational level of meaning for individuals. Here a distinction can be drawn between a social world of routine activities associated with unconsidered risk behaviours, and a situation in which novel / out of the usual events occur. The latter requires an individual to consider alternatives, requiring calculated action, whilst the former does not.

Answer 18

Traditional social studies of the behaviour of young men, particularly those who come from more socially disadvantaged backgrounds, demonstrate that health practices are mediated by and expressed through masculine ‘performances’ within specific settings.‘ This is the idea of proving one’s ‘manhood’ as enacted through disregard for danger. For example, behaviours such as binge drinking, unprotected sex, drunk driving etc. More recent studies have shown that these forms of ‘risky’ behaviour are not confined only to young men, but can be found also in the behaviour of young women.

Answer 19

It has been argued that we are now living through a distinct period of history in which the hazardous environmental costs of industrialisation and globalisation now far outweigh their benefits (see reference - Beck). This is the perspective that technical and scientific ‘progress’ has brought us to the brink of environmental catastrophe. This position references the unintended consequences of nuclear-power, the impact of the internal combustion engine and other sources of carbon emission, global consumption of plastics, etc. These developments are to seen to have resulted in the emergence of what has been termed the ‘Risk Society’. A cultural and social situation in which people are forced, willingly or not, to think through an uncertain future over which they have little or no control. Risk’ therefore becomes not an issue of people acting rationally (or not) according to expert advice, but rather how the culture of a society engages with the prominence of environmental risk to all.

Answer 20

‘Risk’ therefore becomes not a ‘category of understanding’ (rational knowledge of probabilities of the consequences of actions), but rather a ‘category of fear’ (a social ‘fact’ from which there is no exit). What has emerged as a consequence, according to social theorist’s such as Ulrich Beck, is an over-identification of the objects of risk as existing in all spheres of modern society. It is this cultural fear/panic of uncertainty that the proliferation of risk assessment and management strategies (described above) are primarily responding to.

Answer 21

One consequence, is that perceptions of risk can be highly selective or partial. One example would be the issue of peanut allergy. Whilst a real phenomena, the numbers of parents reporting symptoms in their children in the USA has tripled since 1997, leading to panics and health scares (Christakis:2008). The notion of the ‘risk society’ has clear implications for the willingness of individuals to respond to interventions to limit health risk behaviours and to adopt ‘healthy lifestyles’ i.e why change my individual health behaviour when much greater levels of risk are embedded into the fabric of modern societies?

Answer 22

Today, most analysts would probably agree that risk assessment is not a purely objective scientific process. In practice, facts and values often merge (cultural factors intervene) when experts assess issues of high uncertainty, such as health behaviour and its outcomes. Risk communication is more effective when it is structured as a dialogue than as a one-way transfer of facts from experts to the public. We are not mere passive consumers of risk information. ‘ What people “know” about risk is a fluid and changeable concept. Given appropriate stimuli, the “lay person” can become an “expert” in a very short span of time, and her expertise can be all the more formidable because it combines formal technical knowledge with local knowledge that is as relevant as it is unstructured and informal’ (Jasanoff).

Answer 23

All result from ISCHAEMIA of the myocardium, almost always the result of coronary artery atherosclerosis - (no symptoms) - angina pectoris - myocardial infarction - heart failure - heart rhythm disturbances (including sudden death)

Answer 24

9 million deaths worldwide per year Major cause of PREMATURE death Major cause of physical disability

Answer 25

Observational

Answer 26

Definition: A prospective, cohort study is one in which a group of people with different exposures is followed over time to see if they acquire a disease/outcome. Study involves following groups with different exposures forward over time, providing disease incidence (PROSPECTIVE STUDY)

Answer 27

- a strong research design, because exposure is measured before disease develops * - can provide information on several parameters - relative risk, incidence and attributable risk-can look at several exposures and several disease outcomes in one study BUT -not quick or cheap!-challenging when disease studied is rare (* unlike in a case control study)

Answer 28

``` Framingham (1950s) Seven countries (1960s) ```

Answer 29

Hypothesis, confounding factors Size and statistical power of study Selection of study population (needs to include participants with a wide range of exposures) Baseline assessment of exposure and confounders, to identify (and potentially exclude) prevalent disease cases Follow up methods Approach to analysis

Answer 30

Factors associated with both the exposure and outcome of interest eg. blood cholesterol and CHD with age/sex/HBP/smoking/social class

Answer 31

Need to ensure that you design a study big enough to have a good chance of finding an association if present – many studies too small To do this need to consider: How strong an association? (relative risk) How common is the exposure? What is the incidence rate in unexposed group? What p value will be statistically significant? What chance do you want to have of detecting an association if present?

Answer 32

Wide range of exposures from low to high eg gen population or: geographically defined population like Framingham or: well defined population groups like GP, british doctors, civil servants

Answer 33

Consider international cohort study

Answer 34

A highly exposed occupational group: assessing the hazards of occupational exposures, such as asbestos, radiation, & mining exposures Low exposure comparison groups –an internal comparison group of workers in the same factory without exposure –an external comparison group of similar workers without exposure In this way, cohort study can study exposures uncommon in general population (difficult in CCS)

Answer 35

Questionnaire, examination, blood sample, medical records as appropriate Make measurement as objective as possible Repeat assessment if possible to provide `usual’ values, gives more accurate assessment of associations ALSO: Identify and assess potential confounding factors, especially to allow assessment in analysis Assess disease status at outset, to be sure that participant is not already a (prevalent) case of disease, make sure they don't already have a history

Answer 36

Cohort studies allow examination of multiple outcomes if desired Outcome data can come from various sources –routine surveillance systems; death and cancer registers –medical records –questionnaire data –physical re-examination Outcome data collection should be collected independently of knowledge of exposure that participant has Participants may be event free, develop the disease, die for another reason or be lost to follow up- count all of these periods of time to provide indication of incidence rate in group based on new disease cases divided by person years at risk

Answer 37

Risk expresses the number of outcomes per 1000 recruited study members in defined period (e.g. year) Calculate the incidence rate of the key outcome (e.g. CHD event) in the exposed cohort members Incidence rate = number of cases /1000 person years at risk Do the same thing for unexposed cohort members and compare them Relative risk is measured as risk in exposed/risk in unexposed Attributable (excess) risk is the risk in exposed people minus the risk in unexposed people

Answer 38

association is strong and graded

Answer 39

Logistic regression or Cox proportional hazards modelling

Answer 40

- logistic regression takes account of whether an event has occurred during follow-up (0 or 1) - Cox proportional hazards modelling takes account of whether and when incident events occurred, so more precise) Can take account of graded exposures, and for potential confounding (using stratification and adjustment, similar principles as in case control studies) These analyses show an association between circulating total and LDL-cholesterol concentrations and CHD risk – is the association causal?

Answer 41

High levels of circulating cholesterol, particularly: Total blood cholesterol Low density lipoprotein (LDL) cholesterol Apolipoprotein B (Also denoted by total chol-HDL cholesterol (`non-HDL cholesterol’) total chol:HDL cholesterol) ....are positively associated with CHD risk in cohort studies. LDL and ApoB implicated in transporting cholesterol from the liver (where synthesized) to the tissues.

Answer 42

Prospective study measuring cholesterol Followed people over 5-10 years so prospective Analysis adjusted for age and other risk factors so association INDEPENDANT of cofounders

Answer 43

Looking at statins, blocking HMG CoA reductase reducing cholesterol synthesis in body -> reducing circulating total of LDL cholesterol In randomised control trials dramatically reduced risk of CHD events in wide range of people, those who had previous MI or at high risk etc. SIMILAR RELATIVE RISK REDUCTIONS IN DIFFERENT PATIENT GROUPS

Answer 44

High dietary saturated fat intake High dietary saturated fat: polyunsaturated fat ratio Overweight/obesity Genetic predisposition- familial hypercholesterolaemia (1/500 heterozygotes, autosomal dominant)

Answer 45

LDL cholesterol (+ve association w CHD risk) Apolipoprotein B (causal) Triglyceride (+ve association w CHD risk) probs non causal HDL cholesterol (-ve association w CHD risk)

Answer 46

Inverse association w CHD risk

Answer 47

Increased physical activity Increased alcohol intake Lower levels adiposity Being a non smoker

Answer 48

High blood cholesterol (total, LDL, apoB) High BP Cigarette smoking

Answer 49

Diabetes (presence of diabetes increases risk of CHD (and stroke) by more than 2 times(increase especially marked in women and patients with longstanding diabetes)) Adiposity/obesity

Answer 50

Physical activity, moderate alcohol intake, high HDL-cholesterol levels all associated with reduced CHD risk (potentially protective)

Answer 51

Strong overall evidence that they are causal Relative risks associated with exposure are high Risks widespread in the population

Answer 52

high cholesterol (circulating total and LDL) + high BP + cigarette smoking risks MULTIPLY not add CHD risk concentrated in ppl with multiple risk factors

Answer 53

Poor foetal growth and nutrition Inflammation Micronutrient status0 low vit C or low vit D or low folate Evidence inconsistent tho

Answer 54

- A cause is a factor which, of itself, increases the risk of a disease occurring - An event, condition, or characteristic without which the disease would have been less likely to have occurred A risk factor is any characteristic which IDENTIFIES a group at increased (decreased) risk of disease now or in the future

Answer 55

Selection and information bias Selection bias: if there is marked and selective loss to follow up To be a serious problem this would need to involve subjects with a particular exposure-disease combination (e.g. low cholesterol with high CHD risk) being lost to follow-up Information bias: Misclassification of outcome status (disease or not) influenced by knowledge of exposure status

Answer 56

Ensure that follow-up is as complete as possible (minimizes selection bias)- Ensure that assessment of outcome events is carried out without reference to knowledge of exposure (minimizes information bias)

Answer 57

The cohort (longitudinal) study is a fundamentally stronger design because exposure to the potential causal factor is being measured BEFORE disease has developed (not the case in a CCS) Bias (systematic error) can occur either in case control study or a cohort study but is much more likely in a case control study

Answer 58

Very large cohorts and/or pooling of data from several cohorts to add statistical power and precision (Good for studying less strong associations and for studying the interplay of multiple factors, like Prospective Studies Collaboration w 1 million participants from ~60 studies) Nested case control studies within a cohort Historical (retrospective) cohort studies

Answer 59

Within a cohort study, once follow-up has occurred, possible to do a focussed study in samples of incident disease cases and controls (non-cases) and compare exposures – a powerful prospective case control study design (unlike the usual retrospective CCS)

Answer 60

PROSPECTIVE case control study

Answer 61

Historical cohort study – exposures have already occurred and been assessed, cohort established while follow-up is occurring (or has already occurred)

Answer 62

Exposure is measured before disease onset, reducing potential for bias Allows temporal sequence of exposure and effect to be studied (exposure precedes effect – a key Bradford Hill criterion) Multiple outcomes (diseases) can be studied for many different exposures Incidence of disease can be measured in the exposed and unexposed groups Potential for nested case control studies

Answer 63

Slow, expensive, administratively difficult and complex Needs large numbers of participants studied over a long time period Difficult to keep study procedures constant over time Changing exposure and diagnostic criteria over time Ascertainment of outcome status may be influenced by knowledge of exposure Losses to follow up may introduce selection bias (i.e. those left have different health behaviours) Collection of data may alter behaviour of participants

Answer 64

A coherent account of a phenomenon arrived at | through inference and thought. In today's world most people prefer theories that are empirically testable.

Answer 65

To provide an explanation for the phenomenon and to generate predictions. If we can generate accurate predictions then we can manipulate or control the behaviour in question.

Answer 66

Explain a related set of observations. • Generate testable predictions or hypotheses. • Be parsimonious – i.e. involve no more concepts or elements than are necessary. Be the simplest explanation of the phenomenon at hand. • Be comprehensible and coherent. NOT BE CONTRADICTED BY OBSERVATIONS

Answer 67

Spurious correlation, or spuriousness, occurs when two factors appear casually related to one another but are not. The appearance of a causal relationship is often due to similar movement on a chart that turns out to be coincidental or caused by a third "confounding" factor. eg. positive correlation with eating ice cream and drowning, cannot infer causality from this- third confounding factor is hot weather, and correlation drops to zero when you factor this in

Answer 68

An expectancy-value model • E.G. expectancies about the outcome of a particular behaviour relate to ones use of it. - If I believe I can escape a negative consequence by taking precaution e.g. using a condom I am more likely to do so. But it is important to realise factors such as my expectations that this will be protective and my assessment of my ability to take this precaution will also impact on whether I take precaution or not. • The value an individual places on the consequences are also critical to this model. • Critically focuses on perceived threat / susceptibility / barriers and benefits

Answer 69

Allows comparison of different influences on health behaviours Identifies importance of barriers to behaviour change

Answer 70

* Threat does not predict behaviour change for many health behaviours e.g. Smoking, drinking, drugs. * Leaves out emotions, habit, social norms motivations for behaviour change. • Taylor and Brown 1988 – people consistently underestimate their likelihood of being involved in accidents, contracting disease and overestimate their potential. • Does not define how to test relationships between different elements in the model

Answer 71

• Again is an expectancy-value model • Is an intentional theory. Intention is said to be the result of a process that takes account of: – Attitudes – Subjective norms – Perceived behavioural control

Answer 72

* Intentions predict some behaviours * Highlights social norms * Perceived control often the most important factor

Answer 73

Does not adequately address: • Most of the time intentions do not predict behaviour • Past behaviour is often the best predictor of behaviour • Environmental influences • Social support • Habits

Answer 74

• Pashcal Sheeran – Meta analyses of the intention behaviour relationship suggest that intentions generally predict about 28% of the variance in behaviour. • What might predict the rest? • Dostoyevsky’s protagonists – consistently formulate an intention to behave in a certain way but nevertheless find themselves acting in a contrary way. Have you ever experienced something similar?

Answer 75

Stage model of behaviour change * Pre-contemplation – no change contemplated * Contemplation – desire to change within 6 months * Preparation – intend to change in near future * Action – behaviour is changed * Maintenance * Relapse

Answer 76

• Intuitively appealing model which is popular in practice • Predicts change in some behaviours •Broad and has identified many useful processes involved in behaviour change

Answer 77

• Stage definitions are arbitrary and vary widely between studies and lead one to assume this process occurs in all behaviour change which is clearly not the case. • Assumes that change is planned – spontaneous change left out • Pre Contemplation, Contemplation and preparation could be viewed as a continuum of ‘desire’ rather than discrete stages • Doesn’t assess readiness to change. • Doesn’t consider negative processes e.g. wishful thinking, avoidance, blame • Suggests insight into behaviour

Answer 78

Cognitive dissonance theory postulates that an underlying psychological tension is created when an individual's behaviour is inconsistent with his or her thoughts and beliefs. This underlying tension then motivates an individual to make an attitude change that would produce consistency between thoughts and behaviours.

Answer 79

The way to resolve dissonance is to change either belief one or two to make them consonant or to add other beliefs that will resolve the dispute. eg here alter belief 1 and say drinking is not fun, so both beliefs are consonant and the consequence of drinking is no longer there.

Answer 80

* Identity – Who I see myself as influences what I do * Impulses/inhibitory forces/effort/inertia – thought suppression * Momentary priorities – changing priorities * Spontaneous/chaotic change - accidents * Triggers – environmental stimuli * Motives/desires – changing desires * Evaluations – What leads to certain evaluations * Plans - accidents * Memory – state dependent memory * Conditioning – past experience – learned helplessness * Positive illusions – people underestimate risks and overestimate ability

Answer 81

– Common sense: How much do you want to stop smoking? – Transtheoretical model / theory of planned behaviour: Are you planning to stop within the next ....? – Identity theories: As you go about your daily life, how often do you feel very uncomfortable about the fact that you smoke? Is smoking central to your self identity?

Answer 82

(COM-B) • Developed as the former models were inadequate to explain the data seen in practice • Developed to facilitate better links between models and interventions – i.e. to improve the evidence base of behavioural medicine

Answer 83

COM-B (Michie, van Stralen & West 2011) • Model considered the minimum number of factors needed to account for whether change in the behavioural would occur, given sufficient motivation. Two sources used - 1. US consensus meeting of behavioural theorists in 1991 2. Principle of US criminal law dating back many centuries • The US consensus meeting identified three factors that were necessary and sufficient prerequisites for the performance of a specified volitional behaviour: 1.) the skills necessary to perform the behaviour, 2.) a strong intention to perform the behaviour, and 3.) no environmental constraints making it impossible to perform the behaviour. • Under US criminal law, in order to prove that someone is guilty of a crime one has to show three things: means or capability, opportunity, and motive.

Answer 84

Capability = the individual’s psychological and physical capacity to engage in the activity. includes having the necessary knowledge and skills. Motivation = all those brain processes that energize and direct behaviour, not just goals and conscious decision-making. includes habitual processes, emotional responding, as well as analytical decision-making. Opportunity = all the factors that lie outside the individual that make the behaviour possible or prompt it. Interventions may change one or more components in the behaviour system. The causal links within the system then work to reduce or amplify the effect of interventions by causing changes elsewhere. This model provides a basis for designing interventions aimed at behaviour change. The task considers what the behavioural target would be, and what components of the behaviour system need to be changed to achieve that.

Answer 85

All are heavily biased towards us being rational beings making volitional decisions freely – this is contentious None have been instrumental in explaining a majority of statistical variance in behaviour

Answer 86

prevention taking place BEFORE disease is actually present – Aim to prevent disease from developing in the first place

Answer 87

prevention taking place when EARLY DISEASE is present – Aim to prevent recurrence (`cure’) or prevent progression and complications

Answer 88

prevention taking place when ESTABLISHED OR LATE disease is present – aim to limit progression and complications

Answer 89

CHD prevention mainly achieved by reducing exposure to causes – also through altering pathogenesis (use of antiplatelet medications) ``` Reducing exposure to causes – greatest benefits: – The more a causal factor is lowered – The longer the time it is lowered for – Reducing more causal factors – Especially three key causal factors – Circulating LDL-cholesterol level – Blood pressure – Cigarette smoking ```

Answer 90

Relative risk reductions in blood pressure and blood cholesterol are similar in a wide range of people (discussed in earlier BP lecture, also applies for cholesterol lowering) Attributable risk reductions (indicating the benefits of prevention) tend to be greatest in people at high baseline risk of CHD

Answer 91

• People who already have coronary heart disease • People with other atherosclerotic arterial vascular diseases – Stroke/Transient Ischaemic Attack – Peripheral arterial disease • These people are at very high risk of further CHD (death rate ~5% per year) • Principle: Reduce as many risk factors as possible by as much as possible in this group

Answer 92

Health behaviour changes - cigarette smoking cessation (~30% reduced CHD risk) - dietary change (consistent with other health advice) - reduce dietary saturated fat and salt intake - reduce dietary energy intake - increased fruit/fresh vegetables, oily fish - more Mediterranean diet - increased physical activity Medications to reduce as many risk factors as possible by as much as possible (esp LDL-Cholesterol, blood pressure) Statins, beta blocker, ACE inhibitor, antiplatelet agent (eg aspirin) all reduce relative risk individually, this increases to around 70% when combined

Answer 93

STRENGTHS • Can offer intervention appropriate to individual • Because subject at high risk, intervention likely to be:- – Effective – Cost effective • Approach fits within medical model • Motivation of subject and doctor usually high • Avoids interference with low risk population LIMITATIONS • Not a radical approach • No effect on disease incidence (on new disease)

Answer 94

HIGH RISK STRATEGY Identify individuals at high risk for CHD Reduce their risk Clinical approach POPULATION STRATEGY Reduce risk in whole population Public health approach

Answer 95

Single risk factors (e.g. blood cholesterol) not very good when used alone at predicting who will get CHD • Multiple risk factor scores (e.g. Framingham score or QRISK score) to identify subjects with 10 year CHD risk of 20% or more

Answer 96

No fixed agreement -early guidelines focused on people with an annual CHD episode risk of ~3% (30/1000 in 10 years) -more recent guidelines have focused on lower levels of annual risk ~2%, or possibly 1.5% (20/1000 or 15/1000 in 10 years)

Answer 97

Lifestyle changes - cigarette smoking cessation - dietary change - reduce saturated fat and salt intake - reduce calorie intake - increased fruit/fresh vegetables/fish - increase exercise Medications to reduce risk factors and interfere with pathogenesis of CHD

Answer 98

Could use a simpler approach to identify people at high CHD risk– simply select high risk individuals on the basis of age – much simpler than measuring all those risk factors

Answer 99

from BMJ- a pill to prevent 80% of heart attacks ``` “The polypill....could largely prevent heart attacks and stroke if taken by everyone aged 55 and older...” (high risk strategy simply based on age) ```

Answer 100

Are at very high risk of developing CHD, at least double the risk in people without diabetes Tight (improved) control of glucose concentrations in diabetes has a very limited effect on CHD risk BUT Controlling blood cholesterol and blood pressure levels (and stopping smoking) in patients with diabetes a very important part of preventive management in patients with diabetes (even in patients who do not currently have CHD)

Answer 101

STRENGTHS • Can offer intervention appropriate to individual • Because subject at high risk, intervention could be:- – Effective – Cost effective • Motivation of subject and doctor usually high • Approach fits within medical model • Avoids interference with low risk population LIMITATIONS • Process involves risk factor SCREENING which – provides imperfect prediction of those at risk – has costs and risks • Some high risk subjects will have developed disease (secondary not primary prevention) • Not a radical approach, likely to have limited impact on overall incidence in the whole population • Singling out, medicalizing and labelling individuals as abnormal

Answer 102

``` • Population-wide changes in diet (changes in food availability/marketing/pricing) • Lower saturated fat intake • More polyunsaturated fat • More fruit, vegetables, fish, fibre • Lower salt intake ``` * Reducing cigarette smoking prevalence * Price mechanism/taxation * Advertising restrictions * Restrictions on smoking locations • Encouragement of physical activity • Mechanisms – voluntary agreements/ legislation/ education /environmental changes

Answer 103

STRENGTHS • Radical, aiming to reduce disease incidence • Large potential benefits for the population especially where risk is widespread • Behaviourally appropriate - no need for some individuals to behave differently from others • Does not require screening/identification of high risk group • Does not depend on medical care services, which tend to be expensive LIMITATIONS • Usually depends on a sense of public purpose and/or political will - individuals and health professionals are poorly motivated for prevention • Though benefit for the population can be large, the benefit for individuals (even high risk individuals) is small - `prevention paradox’ • If the population strategy involves exposure to a new factor with potential adverse effects (e.g. fluoride into drinking water, medication) balance of benefit and harm may be narrow

Answer 104

It depends on the distribution of disease risk in the population • If most disease cases occur at very average risk factor levels – this would favour a population strategy (this is the case with the cholesterol-CHD association) • If most disease cases occur at very high risk factor levels – this would favour a high risk strategy

Answer 105

LOOK AT OVERALL RISK IN POPULATION (multiply CHD risks by % of population in each group and add up to assess weighted population CHD risk) HEN RECALCULATE AFTER MOVING EACH GROUP (EXCEPT THE LOWEST) TO A LOWER CHD RISK GROUP

Answer 106

• Very strong evidence that antiplatelet medications (e.g. aspirin, even in small doses) reduce relative risk of future CHD (whether or not already have CHD) by about 25% • Effective and widely used in people who already have CHD or other arterial disease and in people at high risk of developing these conditions • However, definitely not recommended for people at low CHD risk, in whom risks of side effects (especially bleeding, in brain or gastrointestinal tract) outweigh the benefits

Answer 107

• Average saturated fat + salt intakes + blood LDL- cholesterol + blood pressure levels remain high • Need to control rising risks of obesity and type 2 diabetes (a challenge to existing CHD gains) • Need to strengthen population-based strategies for reducing CHD risk (especially nutritional) • Need to understand reasons for social and ethnic differences in CHD and use to reduce risks in high risk groups (ethnic minorities esp South Asians and socioeconomically disadvantaged) • Need to control rising CHD epidemic in middle and lower income countries

PPS: Risk Factors, Health Models, Management and Prevention of CHD Flashcards

(141 cards)