Transcript Back to Basics, 2003 POPULATION HEALTH: GENERAL

POPULATION HEALTH:
Health determinants, Prevention &
Health promotion
Ian McDowell
Based on earlier presentations by R.A. Spasoff &
N. Birkett
Epidemiology & Community Medicine
Other resources: SIM web site ; Toronto Notes
April 2011
1
MCC Objectives: Population health 78-1
Concepts of health and its determinants
As defined by Health Canada and the World Health Organization:
1. discuss alternative definitions of health, wellness, illness, disease and
sickness;
2. describe the determinants of health.
3. explain how the differential distribution of health determinants
influences health status, and
4. explain the possible mechanisms by which determinants influence
health status.
5. Discuss the concept of life course, natural history of disease,
particularly with respect to possible public health and clinical
interventions.
6. Describe the concept of illness behaviour and the way this affects
access to health care and adherence to therapeutic recommendations.
7. Discuss how culture and spirituality influence health and health
practices, and how they are related to other determinants of health.
April 2011
2
Objective 1: Definitions of Health
A state characterized by anatomic, physiologic and psychologic
integrity; ability to perform personally valued family, work
and community roles; ability to deal with physical, biologic,
psychologic and social stress..." (Stokes J. J Community
Health 1982;8:33-41)
“Medical model”
Practical, but often
criticized as too
narrow
A state of complete physical, mental and social well-being and not
merely the absence of disease or infirmity. (WHO, 1948)
Classic;
concerns over how
to measure
The ability to identify and to realize aspirations, to satisfy needs,
and to change or cope with the environment. Health is
therefore a resource for everyday life, not the objective of
living. Health is a positive concept emphasizing social and
personal resources, as well as physical capacities. (WHO
Europe, 1986]
Dynamic view; a
capacity rather than
a state
April 2011
3
Definitions of Disability, etc
WHO (1980): International Classification of Impairments, Disabilities &
Handicaps (ICIDH)
• Impairment = loss or abnormality of psychological, physiological, or
anatomical structure or function (e.g., eye injury)
• Disability = resulting loss of ability to function, perform normal
activities (can’t see)
• Handicap = resulting disadvantage due to inability to perform social
roles (loses driving license, so perhaps job)
WHO (2001): Critique of negativity of above leads to International
Classification of Function (ICF). Similar concepts, renamed
impairments, activities & functions. Emphasizes importance of
environment in which person lives.
April 2011
4
Disease
Discussion over conceptions of what is a disease:
• Pathological process? Abnormal condition?
Illness causing discomfort?
• Different nosologies evolve over time
– Syndrome vs. disease
• “Each civilization defines its own diseases…”
(Illich)
• “Non-diseases” (Richard Smith): burnout, senility,
baldness, jet lag, etc. Things doctors should
probably not be treating, but patients hope they
will
April 2011
5
Assembling these concepts
Social
function
(WHO terms in red)
(disadvantage;
loss of
involvement)
Level of impact
(Susser’s terms in green)
Illness
(the patient’s
experience
of being
unwell)
Handicap;
Participation
Disability;
Activity
Sickness
(restriction in
performing
a function)
(socially defined
status of people
who are ill)
Disease
Impairment
Cellular
(loss or
abnormality
of structure
or function)
Disease
signs &
onset
symptoms
April 2011
Time line
(something the doctor
diagnoses and treats)
Diagnosis
consequences
6
Objective 2: Determinants
• Determinants can be seen as underlying social
forces that affect large groups of people
– ‘Causes of the causes’ of disease
– E.g. poverty levels; policies; food prices; doctor
shortage; GNP; …
– May set the incidence rates of disease in society
• Risk factors largely operate at individual level
(age, genetics, health behaviours, etc)
– Affect whether a person is above or below the average
risk for their age & sex
April 2011
7
Health Canada’s list of determinants
Income and Social Status
Social Support Networks
Education and Literacy
Employment / Working Conditions
Social Environments
Physical Environments
Personal Health Practices and Coping Skills
Healthy Child Development
Note that this list blends
Biology and Genetic Endowment
individual and societal
Health Services
factors. But it may be
Gender
the basis for the exam!
Culture
April 2011
8
Objectives 3 & 4: Differential socioeconomic
impact of health determinants
• Individual Poverty associated with increased incidence of
virtually all health problems, often working through known
risk factors (smoking, obesity, etc).
• On a population level, Income inequality is a major factor
in richer nations: refers to the extent of disparities in
income in a society (the spread, or standard deviation, of
incomes).
– The broader the spread of income (even if the overall average is
the same), the worse the life expectancy & other health indicators.
– Seems to operate through decreased social cohesion, community
investment, less supportive legislation, less caring society, etc.
(No Turnbulls!)
April 2011
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Objective 5: Concept of Life Course
Biological programming hypothesis notes long term, cumulative health effects of
early exposures at critical periods (during gestation, childhood, adolescence).
Alternative to the lifestyle explanation of chronic disease.
“Embodiment”: extrinsic factors inscribed into body functions or structures.
Life course approach blends these 2 conceptions: both are important.
Descriptive perspective:
• 0 – 45 = age of misadventure (morbidity from injuries)
• 45 – 75 = age of premature degenerative diseases
• 75+ = age of senescence
Analytic perspective:
• Health is determined by cumulative impact of insults at critical developmental
times + lifetime behaviors, exposures & compensating coping mechanisms
(themselves determined by early experiences). “Accumulation of risk model”
• Child rearing & patterning of behaviours that become risk factors. Links to SES.
– Bowlby: early child attachment determines susceptibility to later psychiatric disorders
– Eepigenetic influences on neural development that establish set points for a range of
physiological parameters
– Barker hypothesis: under-nutrition in utero ‘programs’ the structure & function of body
systems and affect later risk of CVD & diabetes
April 2011
10
Objective 5: Natural history &
interventions
• Distinguish between natural history &
clinical course
• Links to stages of prevention
April 2011
11
Clinical Course of a Disease:
Pre- and post-disease stages
Etiological Phase
Social &
Environmental
Determinants
Risk &
Protective
Factors
Preclinical Clinical Phase
Phase
Post-clinical Phase
Initial
outcome
Living environment
↑
Community
circumstances
(services
available, etc.)
↑
Conditions in
society
(economic
stability, etc.)
April 2011
Personal
factors:
Lifestyle;
Genetics;
Education;
Occupation;
Social
supports,
etc.
Biological Symptoms
onset of
disease
Therapy
Diagnosis
Impairment
Disability
Longer-term
outcome:
Impact on
family
work;
economic
impact, etc.
Handicap
12
Etiological Phase
Social &
environmental
determinants
Primordial
prevention:
Alter societal
structures
& thereby
underlying
determinants
April 2011
Risk &
protective
factors
Primary
prevention:
Alter
exposures
that lead
to disease
Preclinical Clinical phase
phase
Secondary
prevention:
Detect &
treat
pathological
process
at an earlier
stage when
treatment
can be more
effective
Post-clinical phase
Tertiary
prevention:
Prevent
relapses &
further
deterioration
via
follow-up care
& rehabilitation
13
Objective 6: Illness Behavior
1. Utilization of curative services, may seek care
early or may delay (avoidance, denial)
2. Coping mechanisms, change in daily activities
3. Factors affecting adherence to therapy
4. Describe one or more models of behaviour
change, including predisposing, enabling and reenforcing factors
a. Understand the Health Belief Model
b. ‘Stages of change model’
(aka trans-theoretical model)
April 2011
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Modifying Factors
· Demographics (age, sex, ethnicity, etc.)
· Socio-psychological variables (personality,
social class, peer and reference group
pressures, etc.)
· Structural variables (knowledge about
the disease, prior experience of it, etc.)
Perceived Susceptibility
to Disease
Perceived Severity
of Disease
Perceived Threat
of the Disease
Perceived benefits of
taking action, minus
Perceived barriers to
action
Cues to Action
· Raised awareness (e.g., mass media
campaign, newspaper article )
· Personal advice (e.g., reminder from
health professional)
· Personal symptoms
· Illness of family member or friend
April 2011
Likelihood of Taking
Recommended Health Action
15
Stages of Change
“Transtheoretical” model
Action
Preparation
Maintenance
Contemplation
Relapse
April 2011
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Objective 7: Culture & Spirituality
• Culture = shared knowledge, beliefs, and values that
characterize a social group. Learned through socialization.
• Cultural sensitivity = understanding the values and
perceptions of your culture and how this may shape your
approach to patients from other cultures.
• Cultural competence = attitudes, knowledge, and skills of
practitioners necessary to become effective health care
providers for patients from diverse backgrounds.
• Cultural safety goes a step beyond accepting differences,
to appreciating the power imbalances and possible
discrimination that exist, & treating people with respect
April 2011
17
MCC Objectives: Population health 78-3
Interventions at the population level
Enabling objectives:
•
Define the concept of levels of prevention at individual (clinical) and population levels
•
Name and describe the common methods of health protection (such as agent-host-environment approach
for communicable diseases, and source-path-receiver approach for occupational/environmental health).
•
Apply the principles of screening and be able to evaluate the utility of a proposed screening intervention,
including being able to discuss the potential for lead-time bias and length-prevalence bias.
•
Understand the importance of disease surveillance in maintaining population health and be aware of
approaches to surveillance.
•
Describe the advantages and disadvantages of identifying and treating individuals versus implementing
population-level approaches to prevention.
•
Identify ethical issues with the restricting of individual freedoms and rights for the benefit of the
population as a whole
•
Describe the five strategies of health promotion as defined in the Ottawa Charter and apply them to
relevant situations.
•
Identify the potential community social, physical and environmental factors that might promote healthy
behaviours, as well as ways to assist communities in addressing these factors.
•
Be aware of the role of, and work collaboratively with, community and social service agencies (e.g.
schools, municipalities and non-governmental organizations).
•
Demonstrate awareness of the contribution of allied professionals such as social workers in addressing
population health issues.
•
Be able to describe the health impact of community-level interventions to promote health and prevent
disease.
•
Describe examples of public policies which have had an effect on population health.
April 2011
18
Levels of Prevention
• Categories are not black and white.
• Primary prevention:
– Strategies applied BEFORE disease starts.
– E.g. Immunization
• Secondary prevention:
– Early identification of disease
– Screening; thrombolytic therapy of MI
– Some people suggest secondary prevention
relates to reducing the severity of disease.
• Tertiary prevention:
– Treatment and rehabilitation of disease
April 2011
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The ‘epidemiologic triad’ of causal factors
(virulence; infectivity;
Agent addictive qualities;
familiarity of a food, etc.)
Environment
(public health sanitation;
social context; availability
of health care, etc)
April
2011
(Recall
Host
(genetic susceptibility;
resiliency; nutritional
status; education;
motivation, etc.)
the fireman’s mantra: a fire requires air, fuel and heat)
20
Health Protection
• Wide range of activities undertaken by public health
departments & government agencies, such as the Public
Health Agency of Canada (PHAC).
• Includes primordial and primary prevention, such as
– "ensuring safe food and water supplies, providing advice to
national food and drug safety regulators, protecting people from
environmental threats, and having a regulatory framework for
controlling infectious diseases in place. Ensuring proper food
handling in restaurants and establishing smoke-free bylaws are
examples of health protection measures."
• Public health protection deals with reducing threats to the
health of the population, such as biological, chemical, or
physical agents
• Legislation covers identified threats, which can be detected
via surveillance systems.
– Public health policies & healthy public policies.
April 2011
21
Source-Path-Receiver model for
Occupational / Environmental health protection
Source
Path(s)
Receiver
Potential approaches to risk control
Modify
Redesign
Substitute
Relocate
Enclose
April 2011
Absorb
Block
Dilute
Ventilate
Enclose
Protect
Relocate
22
Screening
• Can either:
– Detect pre-disease states (e.g. dysplasia)
– Detect the disease at an early stage
• Criteria for when screening is useful
– Disease criteria
• Serious: Disease causes significant morbidity, mortality
• Early detection can alter the course of the disease
– Criteria related to the screening test
• Valid test: high sensitivity (and specificity if possible)
• Safe, rapid, cheap, acceptable
– Health care System criteria
• Adequate capacity for follow-up & treatment
April 2011
23
Evaluating a screening program: the
hazard of Lead Time bias
Disease
onset
Detectable
by screening
Appearance of
1st symptoms
Death
Time
No screening
Survival after diagnosis
Screening
Survival after screening
Apparent increase in life expectancy
or lead time
April 2011
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Length
bias
Legend
Disease onset
Slowly progressive disease
Rapidly progressive disease
death
Screening identifies 2 cases of rapidly progressive disease and
5 cases of slowly progressive disease
Note:
The incidence of rapidly
progressive disease is equal
to that of slowly progressive
disease
April 2011
Screening
25
Strategies for Prevention:
High Risk Approach
• Identify individuals at high risk and attempt to reduce their
risk, by changing behaviour, etc.
• Logical: high risk people should be motivated to change
• But it may require testing larger population (costs, false
positives)
• Asks targeted people to act differently from their peers
• It may also miss many cases depending on how you define
‘high risk.’ (Most
cases typically occur
in medium-risk people:
see next slide)
April 2011
26
BMI distribution in
the Canadian
population (2007)
BMI
X
Individual risk
of diabetes
over 10 years
=
Population burden: new
cases of diabetes
2007–2017
≥ 35
4%
X 32 % = 129,280 cases
30 to 34.9
13 %
X 21 % = 274,700 cases
12 % of total
26 %
25 to 29.9
41 %
X 10 % = 418,500 cases
40 %
23 to 24.9
22 %
X 7 % = 157,800 cases
15 %
< 23
20 %
X 3% =
61,400 cases
April 2011
Data source: ICES report, June 2010: How many Canadians will be diagnosed with diabetes between 2007 and 2017?
6 % of total
27
Strategies for Prevention:
Population Approach
• Attempts to shift distribution of risk factor
in whole population
• Gets to root of the problem
• Shades into health promotion
• Benefits everyone
April 2011
28
Historically, non-specific population
approaches have had major impact
Annual TB deaths
per million population
Tubercle bacillus
discovered
Chemotherapy
developed
BCG
vaccination
18
40
18
50
18
60
18
70
18
80
18
90
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
4500
4000
3500
3000
2500
2000
1500
1000
500
0
April 2011
29
Health Promotion
Distinguishable from disease prevention in that it:
• Focuses on enhancing health (via resiliency) rather
than avoiding illness
• Takes a broad perspective, covering a range of
issues: not a single pathology.
• Aims to tackle ‘upstream’ factors, enhancing
personal resiliency & coping skills.
• Uses a participatory approach: active community
involvement; often grass roots groups.
– Partnerships with NGOs, Non-Profit groups,
community agencies, social workers, etc.
– Public health physician roles = advocacy, support.
April 2011
30
• Health promotion can be effective in
addressing physical or social environmental
hazards, (e.g., pollution, poverty), usually
through community mobilization
• Environmental interventions are usually more
effective than behavioural ones
• = Emphasis on social environment
• Theme of multiple interventions. Supportive
policies + community agency + individual
engagement
April 2011
31
HP Goals: “Squaring the survival curve”
Health,
Quality of
life
Disability-free survival
Birth
Time
Death
The red line represents a survival curve for a population. The blue lines
represent varying levels of disability among survivors. Squaring the
curve implies shifting these lines up and to the right, towards the
green line, which represents the hypothetical population health limit.
April 2011
32
Health Promotion
• Origins in Health Education; limitations of giving info
• Social Marketing approach
– How to transmit ideas & attitudes: identify needs; demonstrate
advantages; audience segmentation; select channels, etc.
• New approaches based on behavior change theories
– Health Belief model
– Stages of Change model
• Early Risk reduction strategies
• Later Healthy public policy
– Tax policy to promote healthy behaviour
– Anti-smoking laws, seatbelt laws
– Affordable housing
• Community engagement
April 2011
33
Health Promotion
• Ottawa Charter for Health Promotion (1987)
• Five key pillars to action:
–
–
–
–
–
Build Healthy Public Policy
Create supportive environments
Strengthen community action
Develop personal skills
Re-orient health services
Prerequisites for health = peace, shelter, education,
food, income, stable ecosystem, sustainable
resources.
April 2011
34
Objective:
• “Identify the potential community social,
physical and environmental factors that
might promote healthy behaviours, as well
as ways to assist communities in addressing
these factors.”
• Green’s model:
April 2011
35
Planning phase
Start
What can be achieved? What needs to be changed to achieve it?
Identify the
administrative &
financial policies needed
Policies
Resources
Organisation
Service or programme
components
Implementation:
What is the programme
intended to be?
What is delivered in reality?
What are the gaps between
what was planned and what
is occurring?
Identify education,
skills & ecology
required
Predisposing
factors
Identify desirable outcomes:
Behavioural, Environmental, Epidemiological, Social
Lifestyle
Health
status
Enabling
factors
Quality of
life
Environment
Reinforcing
factors
Process:
Why are there gaps between
what was planned and
what is occurring?
What are the relations between
the components of the
programme?
Impact:
What are the programme’s
intended and unintended
consequences?
What are its positive and
negative effects?
Outcome:
Did the programme
achieve its targets?
What can be learned? What can be adjusted?
Finish
Evaluation phase
April 2011
Adapted from: Green L. http://www.lgreen.net/precede.htm
36
Public health ethics
• Underlying principles of
– Respect for autonomy (dignity & making one’s own
choices)
– Beneficence (do good)
– Non-maleficence (do more good than harm)
– Justice (distribute benefits fairly & impartially)
• Four virtues: Prudence, Compassion,
Trustworthiness, Integrity
• Conflicts:
– Beneficence for majority may conflict with autonomy,
e.g. in infectious disease control
– Justice in funding prevention vs. high-tech cure
– Between values in different cultures (e.g. reproduction)
April 2011
37
Ethics topics in MCC exam
• Competency (among elderly, and for adolescents)
– Who makes decisions: proxies, living wills, etc.
• Consent to treatment
– informed consent; battery
– need for repeat consent for 2nd surgery, etc;
•
•
•
•
Withdrawal of care ; assisted suicide
Disclosure: adverse events
Justice
Legal issues: Record keeping
April 2011
38
Some ethical principles in Public Health
Social beneficence versus individual autonomy:
• Isolation & quarantine restrict freedom but are acceptable in communicable
disease control. However, maintain confidentiality & avoid stigma.
• Authority to search for contagious cases is acceptable.
• Mass medication (beneficence vs. nonmaleficence):
– Harm : benefit ratios for immunizations have to accept some individual harm
(should we stop immunization against measles after it is eradicated, thereby
risking returning epidemics?) Risks of not immunizing usually greater; everyone
must be informed.
– Opposition to fluoridation: political or evidence-based?
• Privacy & health statistics (individual autonomy vs. social beneficence)
– Surveillance systems can use anonymous, unlinked data (e.g. from blood test
results)
– Subsequent analyses of medical records for research purposes
– Computerized record linkage
– Issue of research discoveries that damage commercial interests
(e.g. industrial pollution; cigarette companies & lawsuits)
• Informed consent is required for testing (e.g. HIV) (autonomy)
– Debate, however, over anonymity vs. linking to allow for counseling.
April 2011
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(Ethical principles, cont’d)
• Occupational health code of ethics guides balance between
protecting company which employs you and worker.
– Put the health of the worker first; must inform workers of health
threats
– MD to remain fully informed of the working conditions
– Advise management of health threats; workers can inform unions
– Apply precautions
– Must not reveal commercial secrets, but must protect workers’
health
– Only inform management of worker’s fitness to work, not the
diagnosis
• “Crimes against the environment” (pollution, etc) conflict
with economic interests & jobs (which harm health also)
• Legally subpoenaing research records in order to discredit
the data or pursue legal action (e.g. toxic shock case; breast
implant study) not allowed, but variations in ruling.
April 2011
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Population health 78-7 Health of Special Populations
Enabling objectives
Aboriginal health
• Describe the diversity amongst First Nations, Inuit, and/or Métis communities
• Describe the connection between historical and current government practices
towards First Nations, Inuit, Métis peoples (including, but not limited to
colonization, residential schools, treaties and land claims), and the
intergenerational health outcomes that have resulted.
• Describe medical, social and spiritual determinants of health and well-being for
First Nations, Inuit, Métis peoples
• Describe the health care services that are delivered to First Nations, Inuit, Métis
peoples
Global health and immigration.
• Identify the travel histories and exposures in different parts of the world as risk
factors for illness and disease.
• Appreciate the challenges faced by new immigrants in accessing health and social
services in Canada.
• Appreciate the unique cultural perspective of immigrants with respect to health
and their frequent reliance on alternative health practices.
• Discuss the impact of globalization on health and how changes in one part of the
world (e.g. increased rates of drug-resistant Tuberculosis in one country) can
affect the provision of health services in Canada.
April 2011
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(Objectives, continued)
Persons with disabilities..
• Identify the challenges of persons with disabilities in accessing health and
social services in Canada.
• Discuss the issues of stigma and social challenges of persons with disabilities
in functioning as members of society (link to mental health).
• Discuss the unique health and social services available to some persons with
disabilities (e.g. persons with Down’s syndrome) and how these supports can
work collaboratively with practicing physicians.
Homeless persons.
• Identify the challenges of providing preventive and curative services to
homeless persons.
• Discuss the major health risks associated with homelessness as well as the
associated conditions such as mental illness.
Challenges at the extremes of the age continuum.
• Identify the challenges of providing preventive and curative services to
isolated seniors and children living in poverty.
• Discuss the major health risks associated with isolated seniors and children
living in poverty.
• Discuss potential solutions to these concerns.
April 2011
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Aboriginal groups
• Know basic demographics: groups; age pyramid;
• Elevated rates of
– Trauma, poisoning, SIDS, ALTE (Apparent Life Threatening
Event Syndrome)
• also suicide, substance use
–
–
–
–
Circulatory diseases (incl rheumatic fever)
Neoplasms
Respiratory diseases
Infection (gastroenteritis, otitis media, infectious hepatitis)
– Diabetes
• Inuit population probably most acutely affected.
• Questions probably focus on determinants rather
than statistics: list…
April 2011
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Special populations: Seniors
• Risk of
– Musculoskeletal injuries
• includes falls & injuries
–
–
–
–
Hypertension/heart diseases
Respiratory diseases
Dementia
Polypharmacy
April 2011
44
Special populations: Children in Poverty
• Note life course approach (above): lasting
impact of early deficits
–
–
–
–
–
Low birth weight
Trauma/poisoning
Oral problems (abnormalities in teeth and jaws)
Fever/infectious diseases
Psychiatric problems
April 2011
45
Special populations: People with Disabilities
• Increased risk of
– Emotional & psychological problems
– Job insecurity (hence low income & poverty)
April 2011
46
Some MCQs.
April 2011
47
28) In describing the leading causes of death in
Canada, two very different lists emerge,
depending on whether proportional mortality
rates or person-years of life lost (PYLL) are
used. This is because:
a) one measure uses a calendar year and the other a fiscal
year to calculate annual experience
b) one measure includes morbidity as well as mortality
experience
c) both rates exclude deaths occurring over the age of 70
d) different definitions of “cause of death” are used
e) one measure gives greater weight to deaths occurring in
younger age groups
April 2011
48
Which of the following statements concerning crosscultural care is true?
a) It has proven very hard to change physicians’ attitudes
and make them more culturally aware.
b) There still is no formal accreditation requirement to
train physicians in cross-cultural skills.
c) There is considerable literature comparing the
effectiveness of different techniques of cross-cultural
communication
d) Lower quality care results when clinicians fail to
acknowledge cultural differences.
e) The CMA and Royal College have collaborated to
produce clear guidelines on developing cultural
competency.
April 2011
49
26) All of the following statements are true
EXCEPT:
a) one indirect measure of a population’s health status is
the percentage of low birth weight neonates
b) accidents are the largest cause of potential years of life
lost for men in Canada
c) the Canadian population is steadily undergoing
rectangularization of mortality
d) morbidity is defined as all health outcomes excluding
death
e) the neonatal mortality rate is the number of infant deaths
divided by the number of live births multiplied by 1000
April 2011
50
Which of the following statements
about oral health is true?
a) Children with cleft lip or palate are
at increased risk of otitis media.
b) Dental caries may affect a child’s growth
and development.
c)
d)
e) All of the above
April 2011
51
44) Of the five items listed below, the one
which provides the strongest evidence for
causality in an observed association
between exposure and disease is:
a) a large attributable risk
b) a large relative risk
c) a small p-value
d) a positive result from a cohort study
e) a case report
April 2011
52
Which of the following test characteristics are
typical of a screening test?
A. High sensitivity and high specificity.
B. High sensitivity and low specificity.
C. Low sensitivity and high specificity.
D. Low sensitivity and low specificity.
E. Low sensitivity and low accuracy.
April 2011
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23) Which of the following is the most
important justification for mounting a
population screening program for a
specific disease?
a) early detection of the disease of interest is
achieved
b) the specificity of the screening test is high
c) the natural history of the disease is favorably
altered by early detection
d) effective treatment is available
e) the screening technology is available
April 2011
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40) The effectiveness of a preventative
measure is assessed in terms of:
a) the effect in people to whom the measure is
offered
b) the effect in people who comply with the
measure
c) availability and the optimal use of resources
d) the cost in dollars versus the benefits in
improved health status
e) all of the above
April 2011
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42) Each of the following is an example of
primary prevention EXCEPT:
a) genetic counselling of parents with one retarded
child
b) nutritional supplements in pregnancy
c) immunization against tetanus
d) chemoprophylaxis in a recent tuberculin
converter
e) speed limits on highways
April 2011
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12) The following indicate the results of
screening test “Q” in screening for disease
“Z”:
The specificity of test “Q” would be:
a) 40 / 70
b) 120 / 130
c) 40 / 50
d) 120 / 150
e) 40 / 130
April 2011
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13) The positive predictive value would be:
a) 40/70
b) 120/130
c) 40/50
d) 120/150
e) 70/200
April 2011
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43) Which of the following describes the
factors in the classic “epidemiological
triad” of disease causation?
a) host, reservoir, environment
b) host, vector, environment
c) reservoir, agent, vector
d) host, agent, environment
e) host, age, environment
April 2011
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23) Which of the following is the most
important justification for population
screening programs for a specific disease?
a) early detection of the disease of interest is
achieved
b) the specificity of the screening test is high
c) the natural history of the disease is favourably
altered by early detection
d) effective treatment is available
e) the screening technology is available
April 2011
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42) Each of the following is an example of
primary prevention EXCEPT:
a) genetic counselling of parents with one retarded
child
b) nutritional supplements in pregnancy
c) immunization against tetanus
d) chemoprophylaxis in a recent tuberculin
converter
e) speed limits on highways
April 2011
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More MCQs
• Here are some more questions that students
can use to test their own knowledge:
http://www.medicine.uottawa.ca/sim/data/Self
-test_Qs_Pop_Interventions_e.htm
• (The questions contain comments on the
answers, to illustrate why a given response
is not correct)
April 2011
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Ten leading causes of death, Canada, 2006
(sexes combined, all ages)
0
10
20
30
40
Percentage
of all deaths
Malignant neoplasms 29.7%
Diseases of the heart 21.9%
Cerebrovascular diseases 6.1%
Chronic lower respiratory diseases 4.3%
Unintentional injuries (accidents) 4.2%
Diabetes mellitus 3.2%
Alzheimer’s disease 2.5%
Influenza & pneumonia 2.3%
Nephritis, nephrotic syndrome & nephrosis 1.6%
Suicides 1.5%
April 2011
Source: Statistics Canada, http://www.statcan.gc.ca/pub/84-215-x/2010000/tbl/t001-eng.pdf
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