Module 1/2/3 Flashcards
Denominator?
the number of people in a study population
EGO and CGO?
Exposure group occurrence (EGO) = a/EG
Comparison group occurrence (CGO) = b/CG
Epidemiologists measure and compare?
Epidemiologists measure and compare dis-ease occurrences in different groups of people
group and population are used…?
interchangeably.
numerator?
the number of people from the study population in whom dis-ease occurs
numerical measures can be represented as… by..?
Numerical measures can be represented as categorical measures by dividing into different categories
Quanitive data can be?
Categorical or numerical
what do the arrows represent?
Arrows represent time (vertical is incidence, horizontal is prevalence )
what does ‘occurence’ measure?
An ‘occurrence’ describes the transition from a ‘non-dis-eased state’ to a ‘dis-eased state’
What does the circle and square (A,B,C,D) represent? (8)
The circle represents the study-specific denominators.
One exposure group (EG) and comparison group (CG)
Some studies have multiple exposure groups.
The square represents the numerators or dis-ease outcomes A, , b, c, d. (from left to right) A = EG and disease B= CG and disease C= EG and no disease D= CG and no disease
What happens when the study exposure is in numerical measures?
the numerical measures are often converted into categorical measures (two or more). When they are changed it is possible to calculate the occurance
what does the traingle represent?
The triangle represents the Participant Population (P)
What is a population?
A population is any group of people who share a specified common factor
What is Epidemiology?
The study of how much ‘dis-ease’ occurs in groups (populations) and of the factors that determine differences in dis-ease occurrence between two groups
what is incidence?
If the transition from a non-dis-eased state to a dis-eased state is an easily observable ‘event’ then epidemiologists count the occurrences as the number of events over a period of time ( incidence)
what is prevelance?
However if the transition is not easily observable , like transitioning from a non-diabetic to a diabetic state, then epidemiologists count the occurrences as the number of people with the dis-ease ‘state’ at a point in time (prevalence)
What question is involved in epidemiological thinking?
‘what’s the denominator?’
Why do epidemiolgists study negative events?
Epidemiologists tend to study negative events or states, like death or disease, because they are easier to measure than positive states of health such as degrees of wellbeing
why do we use Dis-ease instead of disease?
Use ‘dis-ease’ instead of ‘disease’ to encompass any health-related event or health-related state.
Eg. defining the prevalence of significant asthma as the proportion of a group of people who at the time of asking have had at least two severe asthma attacks in the previous one-year period
This is an example of? why?
This is called period prevalence because the outcome definition depends on the time period specified
How can people leave the prevalence of diseases? Therefore…?
People can leave the prevalence pool either by dying or if they are cured
Therefore a population with a high incidence of disease could have a low prevalence if the death rate or cure rate is also high (vice versa)
How do we often measure the prevelance of diseases?
Often measure the prevalence of diseases at two points of time and calculate the change in prevalence
The difference in prevalence between the two time points is in fact a measure of the incidence of disease over the period between the two time points. (e.g 10/100 had diabetes at one point in time and 20/100 people had diabetes 10 years later, then the prevelance of diabetes increased by 10/100 over 10 years)
how is incidence calculated?
Incidence is calculated by counting the number of onsets of disease (events) occurring during a period of time, and then dividing the numerator by the number of people in the study population.
EGO= a÷EG (/T) CGO= b÷CG (/T)
If the numerator is a count of a categorical then prevelance…?
if the numerator is the sum of the scores for a numerical..?
- If the numerator is a count of a categorical disease states, then prevalence will be a proportion
- If the numerator is the sum of the scores for a numerical outcome measured on everyone then the mean is similar to a measure of prevalence
period prevelance does not include?
Period prevalence calculations do not include the actual number of episodes an individual person has in the calculation
Prevelance measures never include?
A unit of time in their description of the measurement (e.g 10 per 100 people)
There can be more than one…… but always only one….?
More than one EG possible but always only one CG
What are the two epidemiological measures of dis-ease ocurrence?
incidence and prevelance
What does incidence requires? (2)
It requires the disease outcome to be a categorical variable
vertical arrow in the GATE frame
what happens when numerical outcomes are not converted into categories?
We often calculate the mean or median level of the outcome. so
EGO= Σa/EG
CGO= Σb/CG
What is a cohort study? (1)
It is a type of longitudinal study that follows research participants over a period of time. During the period some of the cohort will be exposed to a specific risk factor/charectersitics by measuring outcomes over a period of time.
What is a cross sectional study? (4)
The study takes place at a single point in time.
Used to describe what is happening at the present. (think of a cross sectional study as a snapshot of a particular group of people at a given point of time)
it does not involve manipulating variables
it’s often used to look at the prevailing charactheristics in a given population
What is prevelance calculated by?
Prevalence is calculated by counting the number of people with a dis-ease at one point of time and then dividing by the number of people in the study group at that point in time
What is the most appropriate measure of disease occurrence?
incidence as it has an easily observable onset
what’s always included in calculation of incidence?
Time
Why are some observable events still measured with prevelance?
Some diseases that do have observable onsets or events are still best measured as prevalence if the events come and go frequently - eg asthma attacks
Why is period prevelance a mix of incidence and prevelance?
Period prevalence is a mix of incidence and prevalence because it initially involves defining the presence of dis-ease based on the number of onsets that have occurred over a period of time, and then converting this into a single measure of disease at a point in time
Why is prevelance less useful? What type of arrow in the gate frame?
Prevalence is less useful than incidence because it is dependent on the death and cure rates
Horizontal arrow in gate frame
Allocation- What are measurement errors?
Inaccurate measures of exposures are usually known as measurement errors but as they can result in participants being allocated to the wrong exposure/comparison group , we consider them to be a type of allocation error ( allocation measurement error )
Allocation- What happens in observational studies (EG or CG) (2)
In observational studies the EG and CG are frequently quite different from each other in many respects and we usually try to adjust for these differences in the analyses ( age standardisation etc )
Important to collect sufficient information about the differences between EG and CG that can be used for the adjustments
Allocation- What happens in some small RCT’S? (2)
In some small RCTs, randomly allocating participants may not produce groups with similar characteristics just by chance alone
So always important to check for differences between EG and CG at the beginning of a study- called a ‘baseline comparison’ and should be done whether the study has allocated participants by randomisation or by measurement
Most epidemiological studies are designed to do what?
Most epidemiological studies are designed to investigate whether there are differences in disease occurrence between exposure and comparison groups within a study population
Recruitment- What is confounding error (caused by allocation)?
When the participants who are allocated to the exposure group are recruited from a different source than the participants allocated to the comparison group
Recruitment- What is involved in gate triangle (6)
Top represents setting
Rest of the triangle represents the eligible population
Tip of the triangle represents those from the eligible population who agree to take part
Often only a small proportion of the eligible population agree to participate in a study
If the non-responders are different from the responders, this can cause a recruitment error
Response rate of less than about 70-75% could cause significant recruitment error
relative risk greater than 1.0? What is it usually represented as? (2)
Relative risk increase. The RRi is usually expressed as a percentage increase, calculated by sibtracting 1.0 from the relative risk and then multiplying by 100.
RRI= (RR-1) x 100
e.g if the RR= 2.0 then the RRI= (2.0-1) x 100= 100% higher risk of…
Relative risk less than 1.0 can be expressed as? (3)
Relative Risk Reduction (RRR) because it is reduced below 1.0 (i.e the no-effect value).
The RRR is usually expressed as a percentage and is calculated by subtracting the relative risk from 1.0 and then multiplying by 100.
e.g heart attack (not taking the drug)= 10/100
(taking the drug)= 7/100
RR= 7/100 ÷ 10/100= 0.7
RRR= (1.0-0.7) x 100= 30%
What are non random errors?
Errors caused by problems with how the study is designed or conducted are called non-random errors (biases, systematic errors or validity problems)
What are random errors?
Errors caused by chance are described as random errors
What are the two main ways to compare two-disease occurrences?
EGO/CGO = relative risk (may be called a risk ratio)
EGO - CGO = risk difference (absolute risk difference to distinguish it from a relative risk (more appropriate measure))
What are two main ways of allocation?
- Randomly (reduces confounding ) ( experimental )
2. Allocate participants by measurement ( observational )
What happes in s ‘double blind’ randomized controlled trial (RCT)?
neither participants nor investigators know which intervention was given to which participant. They are like cohort studies except participants are allocated randomly to EG or CG.
What is an RCT?
A randomized controlled trial (RCT) is the best type of study to answer questions about the effect of treatments (but only if it is both ethical and practical)
What is in allocation random error? (2)
“Were the study participants successfully allocated to the Exposure Group (EG) and the Comparison Group (CG)?”
- If EG and CG differ in ways apart from the study ‘exposure’, and if these other differences also have an effect on the study outcome, then it’s not possible to know whether the study exposure or the other factors caused EGO and CGO to differ ( confounders )
What is it called when calculating the difference between two means?
if outome measures are calculated as means (averages) the difference between two means are called the mean difference (MD).
What is recruitment error? (3)
When the study findings are not applicable to a wider population
Commonly occurs when the main objective of the study is to measure the characteristics of a specified eligible population but the Participants (P) who are recruited are not representative of the Eligibles
In many studies it is unnecessary to recruit participants who are representative of a specified external population ( only when measuring prevalence in entire population)
What is the 95% confidence interval?
The 95% confidence interval is used to describe the amount of random error in the study results.
“there is about a 95% probability that the true value of EGO in the whole population of interest, from which the study participants were recruited, lies between 8.0 and 10.0”
What is used within the gate frame to indicate that there may be more than 2 exposure groups? (2)
Dotted horizontal and vertical lines are used within the GATE frame to indicate that there may be more than two exposure groups and more than two outcome groups
Alternatively either or both exposures and outcomes can be numerical measures
When is the RD considered an ARR or ARI?
If the risk is lower in the exposure group (ARR) or if the risk is higher in the exposure group (ARI)
Adjustment- stratified analysis- What is direct age-standardisation?
Direct age-standardisation - when disease incidence or prevalence in different populations with different age structures are compared. Each population is stratified into comparable age groups and disease incidence or prevalence is calculated for each strata. Then each population’s age structures are standardised and a standardised disease measure is calculated for the combined age strata
Adjustment- what is strata?
Confounding can be reduced by dividing participants into ‘strata’ , and then analysing the data as if there were two separate studies
The results of the analyses in the different strata can then be combined , if they give reasonably similar results
how can confounding in allocation occur? how is it solved and when is it possible? (3)
Confounding can still occur in a large RCT if the random allocation process is not done properly
Solved by concealment of allocation
Randomisation is only possible when the exposure being investigated is considered to be safe
What are the strengths of cohort studies? (2)
Cheaper than RCTs
Exposure measured before outcome, avoiding recall bias and providing clear time sequence between exposure and dis-ease outcomes
What are the weaknesses of cohort studies? (3)
How accurate was allocation (measurement)
How similar are EG and CG (confounding)
How well maintained in EG and CG
What happens if results are not statistically significant? (2) What is the width of the CI dependant on?
“Too much random error to determine if there is a real difference between EGO and CGO”
The width of the CI is dependent on the number of events that occur in a study
What happens in statistically significant results (large overlap)?
When there is a large overlap between 95% CIs for EGO and CGO - the study is unable to determine if EGO is different from CGO in the population from which the study participants were recruited.
What happens in statistically significant results (no overlap)? (2)
When there is no overlap in the CIs for EGO and CGO it is reasonable to assume that EGO and CGO are truly different from each other
The confidence intervals for RR and RD will not cross the no-effect line
What happens when maintanence errors are small? How is it improved? (2)
As long as any maintenance errors are small and similar in both EG and CG, the error will underestimate the true effect of the exposure on the study outcomes (this is considered preferable to not knowing whether the error will exaggerate or underestimate the true study effect measures)
Maintenance error improved by keeping participants/study practitioners blind
What is a 95% confidence interval statement?
“There is about a 95% chance that the true value in a population lies within the 95% confidence interval”
“In 100 identical studies using samples from the same population, 95/100 of the 95% confidence intervals will include the true value for the population”
What is blind or objective measurement error?
Can cause outcome measurement errors
Blinding or double blinding improves outcome allocation when the measurement is not very objective
Or use objective measurements wherever possible eg blood tests instead of questionnaires
What is clinical significance?
If a clinician would make the same clinical decision whether the true result was at one end of the confidence interval or the other
What is cohort study commonly used for? (2)
Commonly used for investigating risk factors for disease with large effects, as usually unethical to do RCTs
Not very useful for studying benefits of interventions with small effects because confounding may hide a small harm
What is maintenance error? (4)
Maintenance error caused when…
Participants do not maintain their exposure and comparison status throughout the study ( switch groups )
Are exposed to other factors that could influence the study outcomes
Drop out of the study
What is meta-analyses? (3)
Combining the results of a number of small studies is similar to conducting a larger study and reduces the amount of random error
Can change conclusion of study (from statistically not significant to statistically significant)
When none of the individual studies are large enough to give a precise enough estimate
What is random allocation error?
The EG and CG in a randomised controlled trial may differ by chance alone, particularly if the trial is small
What is random error? How can they be reduced? (2)
Errors that occur due to chance
Most random errors can be reduced by increasing study size or by increasing the number of times a factor is measured on each participant
What is random measurement error?
Our ability to measure biological factors in exactly the same way every time we measure them is often poor
What is random sampling error?
Every representative sample recruited will be slightly different from every other sample just by chance
Inherent in every study because every study population can only be a sample of the total population of interest
The bigger the sample chosen, the smaller the differences between the sample and the total population
what is the randomness inherent in biological phenomena?
Inherent variability in all biological phenomena and therefore inherent variability in all measurements of biological phenomena
Take multiple measurements then average the results
How to deal with confounding variable?
Divide the study into substudies (or strata) so participants with the confounder are all in one study.
What are the strengths of a cross setional study
No maintenance error as no follow-up
Cheap and completed quickly
Best design for assessing prevalence
What are the weaknesses of RCT?
Random error common because they are expensive so often the number of participants is small and the length of follow up short
Ethical limitations
Long-term follow up difficult and costly
Maintenance error
What does meta analysis not influence? (2)
But doesn’t influence amount of non-random error
What is ecological study?
a study of population (longitudinal and cross-sectional)
What is the strength and weaknesses of ecological study? (4 altogether)
Problems:
Confounding very common
Strengths:
Cheap and quick
Useful when the majority of some populations are exposed but others are not
Efficient for rare outcomes
What is the strength of RCT?
Confounding is minimised (if random allocation is done properly)
What is the weaknesses of cross sectional study? (3)
Uncertain time sequence (possible REVERSE CAUSALITY)-limits interpretation of cause and effect
Confounding
Important to recruit a representative sample of a population if you want to measure prevalence in that population
What is RCT? (longitudinal study)
study of individuals randomly allocated to groups and then outcomes counted over time
individual vs population health (individual)
“Clinicians” generally deal with individuals. They aim to treat disease – to restore “health
- Interested in all those who have the disease, and interested in all those
that are in the early stages, and interested in physical and social environment.
individual vs population health (population health) (3)
- Concerned with the health of groups of individuals, in the context of their environment
- Interested in identifying & treating all appropriate patients in a population
- More comprehensive, proactive population approach.
What does the public/population health framework involve?
- define the problem
- cross sectional studies - identify risk and protective factors
- cohort studies
- case-control studies - develop and test prevention strategies
- RCT
- Diagnostic test accuracy studies - Assure widespread adoption
- evaluative studies
What is the cause of the problem in relation to the public/population health framework?
- An important role of epidemiology is to seek the cause of “dis-ease”, so appropriate preventive measures can be introduced
- Epidemiology determines the relationship or association between a given exposure and dis-ease in population
What are the main points of the Bradford hill criteria?
- Temporality,
- Strength of association,
- Consistency of association
- Biological
gradient (dose-response) , - Biological plausibility of association,
- Specificity of association
- Reversibility Judgement!
1) temporality
- First the cause then the disease (e.g smoking
====> lung cancer deaths) - Essential to establish a causal relation
2) strength of associated
The stronger an association, the more likely to be causal in absence of known biases (selection,
information, and confounding). (British Drs
study RR>10)
3) Consistency of association
- Replication of the findings by different investigators, at different times, in different places, with different methods . (multiple studies have shown similar results).
4) Biological gradient (dose-response)
- Incremental change in disease rates in conjunction with corresponding changes in exposure
- Biological plausibility of association - Does the
association make sense biologically? (chemicals
in tobacco are known to promote cancers)
5) Specificity of association (weakest criteria)
- A cause leads to a single effect or a an effect has
a single cause. However, health issues have multiple, interacting causes and many outcomes
share causes.
6) Reversibility
- The demonstration that under controlled
conditions changing the exposure causes a
change in the outcome.
What is defined as a cause of disease:
An event, condition, characteristic (or combination of these factors) which play an
essential role in producing the disease
What are the 3 main points of framework 2 casual pies (KJ Rothman)
sufficient cause
component cause
necessary cause
casual pies- Sufficient cause
- A sufficient cause i s a factor/s that will inevitably produce the specific dis-ease.(the entire pie)
Casual pies- Component cause
A component cause is a factor that contributes towards dis-ease causation, but is not sufficient to cause dis-ease on it’s own (triangles in the pie including necessary cause).
What are the determinants of health for population defined as?
- Concepts are similar as for individuals, but nature of determinants is often different
- Not just application of the individual perspective to whole population, but includes characteristics of the population itself.
- Determinants of health in populations are also related to the context in which the population exists.
Often, determinants and actions/interventions designed to improve population health are
discussed the analogy of a river
What are examples of the determinants of health?
- Income
- Employment
- Education
- Housing and
- neighbourhoods
- Societal characteristics e.g. racism, attitudes to
- alcohol or violence, value on children
- Autonomy and empowerment – social cohesion
What are downstream interventions?
operate at the micro (proximal) level, including
treatment systems, and disease management
What are upstream interventions?
operate at the macro (distal ) level, such as
government policies and international trade agreements
What are proximal determinants?
- A determinant of health that is proximate or near to the change in health status;
- ‘near’ generally refers to any determinant that is readily and directly associated with the change in health status. E.g. lifestyles and
behavioural factors related to nutrition or smoking or other exposures.
What are distal determinants?
- A determinant of health that is either distant in time and/or place from the change in health status.
- Distal determinants of health are also referred to as ‘upstream factors’. E.g.
national, political, legal and cultural factors that indirectly influence health by acting on the proximal factors.
What are the three levels of influence?
The person
The community
The environment
three levels of influence (individual) (12)
● Age, sex, constitutional factors & individual lifestyle factors ● At the core of the Dahlgren & Whitehead model are factors that are sometimes referred to as ‘non- modifiable’ determinants: genes and biology ● There are important distinctions between the impact on individuals and populations ● – Single gene disorders = rare among the population ● – Polygenic inheritance = influences likelihood of offspring ● developing a disease ● Genes are important, but so too is the influence of the environment ● There is a wealth of evidence demonstrating the importance of food, exercise, and risky behaviours in relation to health outcomes. ● – Remember the social gradient ● The choices you make as an individual impact on the likelihood that you will have good(or bad) health ● Habitus: lifestyle, values, dispositions and expectation of particular social groups ‘learned’ through everyday activities ● – Ability to change behavior(s) may vary by social group
Three levels of influence (community) (6)
● Social and community networks Living and working conditions ● Families and friends play a significant role in developing ‘normative’ behaviours ● Attitudes and behaviours of people living and working in the local community influences the sense of what is normal and acceptable ● Social capital - the value of social networks that facilitates bonds between similar groups of people ● – provides an inclusive environment for people from diverse backgrounds ● – Civic participation, volunteerism, supportive communities “it’s not what you know, but who you know”!
Three levels of influence (environment) (13)
● General Socioeconomic,cultural and environmental conditions ● Physical Environments ● – Water quality, clean air, all living things ● Built Environments ● – Design of communities: buildings, roads, light rail ● Cultural environments ● – Knowledge, beliefs, and values that are accepted by a group of people ● Biological Environments ● – Emerging or re-emerging toxins affecting populations ● The Ecosystem ● – Biodiversity, climate change, the ecological footprint ● Political Environments ● – Approaches to improving population health
What are the four capitals?
Natural capital
Human capital
social capital
financial/physical capital
The four capitals (natural capital)
All aspects of environment needed to support life and human activity. Includes
soil, water, plants and animals
The four capitals (human capital)
People’s skills, knowledge and physical and mental health
The four capitals (social capital)
Describes the norms that underpin society e.g trust, the rule of law, Crown Maori
relationship, cultural identity
The four capitals (financial/physical capital)
Includes things like houses, roads, buildings, hospitals, vehicles etc. These are the things that make up the country’s
physical and financial assets which have a
direct role in supporting incomes and living
conditions.
‘structure’ in population health
Social and physical environmental conditions/patterns (social determinants) that influence choices and opportunities
available
‘agency’ in population health
The capacity of an individual to act
independently and make free choices
What is the determinants of health framework?
- Is a framework to help you identify risk or protective factors and consider levels of
intervention - Age, sex & hereditary factors are non-modifiable , other determinants are
modifiable
what is the permeability between factors in the determinants of health framework?
- No arch operates in isolation from the others
- Events at one level may impact on factors at another (higher or lower) level
how doe the determinants of health framework recognize the determinants operating at different scales?
- Upstream (distal ) or downstream (proximal )
- Micro (individual), meso (family, living, work), macro (national/global)
“Inequities in health outcomes result from inequities in opportunities”
What is inequalites?
- Measurable differences or
variations in health - differences in health experience and outcomes between different population groups - according to SEP, area, age, disability, gender,
ethnic group i.e the social gradient
What is inequities?
- Those inequalities that are deemed to be unfair or stemming from some form of injustice.
- Health inequities are differences in the distribution of resources/services across
populations which do not reflect health needs - Relations of equal and unequal power ( • political, social and economic as well as justice and injustice)
why look at maori?
● Maori health population model to use for the betterment of whole of population
● Inequities
● Rights as indigenous people and treaty partners
● Maori health is everyone’s responsibility
what are systematic inequalities?
● Health system inequalities quality/accessibility (health outcomes)
● Lack of representation in the health system
● Health system responsiveness
Ethnic inequalities are not by chance and are perpetuated in the system therefore can be
decreased/eliminated/prevented
What causes health inequality?
Ethnic inequalities due to unequal distribution of health risks and opportunities
(social determinants). Housing,poverty,jobs therefore affect life expectancy/health
outcome.
What are conventional health promotion?
● Based on Western models
● Universal formula (one size fits all)
● Often simply adapted for Ma ori
● Doesn’t incorporate Maori values and realities
● Has tended to benefit non-Maori to a greater extent than Maori
● Superficial vs structural approach
⇣
- Misses fundamental issues eg low socio economic, jobs etc. therefore message usually taken on by privileged communities.
Eg promotion on healthy eating- may work on a privileged person however parents who cannot afford to give their children a ‘trip’ for example would compensate to them by giving them a can of coke everyday,treat them in an affordable way- the
structural approach here would be to lift that population out of poverty while simply putting on posters would be a superficial approach
- Need to perhaps distribute equally as everyone doesn’t have the same starting point.
what are the models of health promotion? (maori)
● The Ottawa charter
● Te Pae Mahutanga
ottawa charter (6)
Prerequisites – peace, shelter, education, food, income, stable eco-system, sustainable resources, social justice & equity ● Build healthy public policy ● Create supportive environments ● Strengthen community action ● Develop personal skills ● Reorient health services
Te Pae Mahutanga (4)
● Developed by Professor Sir Mason Durie
● Based on the Southern Cross as a navigational aid
● 4 central stars (key tasks) and 2 pointers (pre-requisites)
● Fundamental components of health promotion from a Maori world view – “but as they might also apply to other New Zealanders”
What are the four key starts of Te Pae Mahutanga
Mauriora
waiora
toiora
te oranga
what is mauriora?
maori cultural access “te reo, customs, marae (maori world)
What is waiora?
Environmental protection
What is toiora?
Healthy lifestyle, safe sex, exercise heatlhy, eating diet.
what are the two prerequisites of te pae mahutanga?
Te Manukura
Te Mana whakahaera
What is te manukura?
leadership
health professional and community leadership
What is te Mana whakahaera
Autonomy
capacity for self governance, community control/enable political levels
what are the principles of maori health? (9)
Promotion- SIDS (infant deaths) align with stars • By Maori for Maori (for everyone)-maori at decision making levels • Self determination and control • Valid models, frameworks, concepts • Maori people, values, collectives • Contemporary tools and methods • Allows for diverse realities • Focus on determinants of health • Evidence-based
What are the key points of maori health? (6)
• ‘Mainstream’ health promotion interventions have generally been less effective for Maori
• Health promotion needs to address the basic determinants – not just the surface causes
→ Understand the whole Ottawa Charter
• Maori have different historical/social/cultural
contexts; one-size-fits-all approach won’t work
• Te Pae Mahutonga is an example of a Maori model of health promotion
• The principles of Maori health promotion may be applicable in ‘whole population’ approaches
What is the importance of preventing disease (4)
- Epidemiology can play a central role in preventing disease by: unravelling the causal pathway, directing preventative action, evaluation of effectiveness
- The need for prevention is growing as limitations in curing disease become apparent and as the costs of medical care escalate
- Because of limitations - some populations cannot utilise the medical care
- Lead to inequalities in health
what are the 3 population health actions?
Health promotion Disease prevention Health protection - population based (mass) strategy -high risk (individual) strategy
What is population based strategy focus?
- Focus on whole population
- Reduce health risks & improve health outcomes in whole population
- Move distribution of health outcomes for EVERYBODY in the population
E.g: immunisation, seatbelts, low salt foods
What is individual strategies focus?
Focus on individuals perceived to be at high risk
- Improve health outcomes of high risk individuals
- Well matched to individuals and their concerns
- E.g interventions
What is population based strategy advantages?
Radical - addresses underlying causes,
- Large potential benefit for whole
population - change behaviour in society
- Behaviourally appropriate - e.g smoking
What is population based strategy disadvantages?
- Small benefit to individuals - Eg (seatbelts)
- Poor motivation of individuals - don’t see
themselves as at risk - Whole population is exposed to downside
of strategy (less favourable benefit-to-risk ratio) Risk faced by everybody, benefit to those that are in accidents)
What is individual strategies advantages?
Appropriate to individuals -
targeted
- Individual motivation
- Coast effective use of resources - targeting those who need it most
- Favourable benefit to risk ratio - benefits outweigh risks
What is individual strategies disadvantages? (4)
- Cost of screening, need to identify individuals
- Temporary effect - e.g breast screening programme new cohort
of people eligible for screening, run every year - Limited potential -
- Behaviourally inappropriate -
cultural clashes e.g traditional food, might be insulting
What is health promotion?
- Acts on determinants of well-being
- Health/wellbeing focus
- Enables/empowers people to increase control over, and improve, their health
- Involves whole population in every day contexts
what are the three types of healthcare services?
primary
secondary
tertiary
primary healthcare services
Patients regular source of care e.g GPs, pharmacists, physiotherapist, community
based
secondary healthcare services
Specialist care (e.g. Neurologists, dermatologist)
tertiary healthcare services
Hospital based care, Rehabilitation
Alma Ata 1978: declaration for PHC
- First time PHC was seen as key to achieving healthcare
- Protect and promote health of all
- Advocated a health promotion approach to primary care
what are the prerequisites for health? (7)
- Peace and safety from violence
- Shelter
- Education
- Food
- Income economic support
- Stable ecosystem and sustainable resources
- Equity
What does the otawa charter 1986 for health promotion acknowledge?
it acknowledges that health is
- A fundamental right for everybody
- Requires both individual and collective responsibility
- Opportunities for good health should be equally available
- Good health essential element of social and economic development
What are the 3 basic strategies of the Otawa Charter?
Enable
Advocate
Mediate
strategy: Enable
- To provide opportunities for all individuals to make healthy choices through access to information, life skills and supportive environments (individual level strategy
strategy: Advocate
- Create favourable social, cultural and physical environments by promoting/advocating for health and focusing on achieving equity in health
Strategy: mediate
- To bring together individuals, groups with opposing interests to work together/ come to a
compromise for the promotion of health
what are the 5 priority action areas of the ottawa charter?
- Develop personal skills
- Strengthen community action
- Create supportive environments
- Reorient health services towards PHC
- Build healthy public policy
What is disease prevention?
- Disease focus
- Looks at particular diseases (or injuries) and ways of preventing them e.g. the incidence, the prevalence, risk factors, or impacts
- Understand natural history of disease and prevention strategies
disease prevention: primary
-
- reduce exposure of risk factor
- Limit the occurence of disease by controlling specific causes and risk factors e.g seat belt regulations
disease prevention: secondary
reduce the more serious consequences of disease
e.g screening people 65+ for risk of hip fractures
rescue services for prevention of drowning
disease prevention: tertiary
reduce the progress of complications of established disease
e. g counselling services for people with post traumatic stress disorder (PTSD)
- rehabilitation services for burn patients
What is health promotion?
• Predominantly environmental hazard focused
• Risk/Hazard assessment:
- Environmental epidemiology
- Safe air and water, biosecurity
• Monitoring
- e.g. biomarkers of exposure to hazardous substances
• Risk communication
- e.g. relating environmental risks to the public
• Occupational health
- e.g. safety regulations on work sites
health promotion focus
health wellbeing
disease prevention focus
disease
health protection focus
environmental hazards
health promotion actions
acts on determinants of wellbeing
health prevention actions
- ways of preventing incidence, prevelance, risk - factors or impacts
3 levels
health protection actions
- risk hazard management
- monitoring
- risk communication
- occupational health
Why measure SEP? (5)
- Are used to quantify the level of differences and inequalities within or between societies (eg. most advantaged
- group and least advantaged group - why, and what are the implications for each group?)
- May highlight changes to population structures over time, between Census periods or even between generations
- Are need to help understand the relationship between health and other social variables (age, sex, ethnicity) → can help with allocation of funding to imrpove health
- Have been associated with health and life chances for as long as social group have existed - SEP has existed for hundreds of years: living on the “wrong side of the
tracks” (downwind) meant you had lower life expectancies
Measuring SEP for populations
- Education (younger)
- Income
- Occupation
- Housing (type, quantity, quality, etc)
- Assets and wealth (more effective for over 65s - no point asking a 90yr what their highest level of education was)
measuring SEP for populations
- Area measures
- Deprivation
- Access
(how we measure these will be covered in later lectures) - Population measures
- Income inequality
- Literacy rates
- Gross Domestic Product per capita
( GDP: monetary measure all final goods and services produced in a specific time period) Refer back to Systolic BP in London Civil Servants and Kenyan Nomads
when making policies what do we need to consider?
The population we are serving
what is the stronger predictor of health and ahy?
Recognise that education is the strongest predictor of health; it is the gateway into occupation and higher income that influence
health outcomes
- Individuals with the lowest level of qualifications are more likely to report poor health
- Income is a very static measure (wtf does this mean he doesn’t explain anything)
what is the most common area-based measures of SEP
Index of deprivation (IMD)
How is addressing inequalities political?
- Population health is deeply connected to politics
- Govts. Want to improve health and wellbeing of society
- However, HOW improvements can be approached differs widely (NOTE: ‘health’ is
very wide - education? Individual responsibility? Closing wage gap? Employment?
Housing? - where are resources being put in?) - So, different allocations by different political parties to improve health - some more
effective than others
Why is it important to consider equity for whom?
- In some cases, interventions do not close gaps between groups; they may contribute to widening it
- This is because there are barriers that prevent lower SEP groups from accessing the intervention, so it is only useful for higher SEP groups (so only they reap the benefits)
- Thus, it is important to consider the factors that may influence equity:
Progress
Place of residence Race/ethnicity occupation gender/sex religion education ses social capital
what measures are used to measure the effect of inequities?
- Rate Difference (RD) - absolute measure
EGO - CGO - Rate Ratio (RR) - relative measure
EGO/CGO
where should deprivation be applied to and why?
Deprivation should be applied to conditions and quality of life that are of a lower standard than is ordinary in a particular society
Living in poverty refers to a lack of income and resources to obtain the normative standard of living
What is NEET?
Not in Education, Employment, or Training(NEET), refers to a person who is unemployed, not in school or vocational training.
As the proportion of NEET increase, life expectancy decrease
What are the global determinants?
Income inequality National income GDP Literacy rates Free trade agreements
Why is population data important?
To look at the denominator Measuring the trends Births Mortality Morbidity Migration More applied work unemployment/benefit claimants/pensions Crime Health service utilisation Voter turnout Education pathways
