hltb16 final exam

Population approach:

• Targets the entire population regardless of individual risk levels  

High-risk approach:

• Focuses on individuals at the highest risk for a disease

• Who came up with the population approach?

• Created by Geoffrey Rose, a British epidemiologist 

High-Risk Approach advantages

• Efficient use of resources: Targets only those who need it most.

• Big benefit for the individual: High-risk people can improve their health a lot by reducing their risk.

• Easier to motivate individuals: Their personal risk is obvious to them.

High-Risk Approach disadvantages

• Does not reduce risk for the whole population: Most disease happens in people who are not very high-risk.

• Limited impact on overall public health.

• Can miss people who are at “medium” risk but still contribute to many cases of disease.

• Requires screening, which can be expensive and time-consuming.

Population approach advantages

• Big impact on public health: Even small improvements across millions of people reduce disease a lot.

• Addresses root causes (social, environmental, lifestyle).

• Does not require screening—everyone benefits.

• Cost-effective for society when applied broadly.

Population approach disadvantages

• Small benefit to each individual: Each person may only gain a tiny improvement.

• Harder to motivate individuals—small personal benefit feels less urgent.

• May require political support, laws, or policy changes.

• Industry or public pushback (e.g., food industry, tobacco industry).

Universal vs. Targeted Interventions differences

Universal Interventions: Actions or programs aimed at everyone in the population, regardless of their level of risk. Examples: laws, taxes, national campaigns, school-wide programs.

Targeted Interventions: Actions aimed at specific groups who are at higher risk or have greater need. Examples: Special support for vulnerable families, high-risk youth programs, extra services for low-income groups.

The Public Health Agency of Canada applied the Ottawa Charter and developed an “integrated model of health promotion”. What does this entail?

• In planning a health intervention, the integrated model asks:

•  Who needs the intervention?

•  What should the intervention target?

• How should the objectives be achieved?

Community mobilization

• engaging and organizing community members to take collective action on health issues. It leverages local knowledge, resources, and participation to plan, implement, and sustain interventions that improve health outcomes.

What is Harm Reduction?

Public health approach that aims to minimize the negative health effects of risky behaviours without necessarily eliminating the behaviour. Focuses on practical, evidence-based strategies to reduce health risks, balancing ethics, public health, and individual behaviour.

Rationale about harm reduction

• Recognizes that some behaviours (e.g., drug use, smoking, unsafe sex) will occur, so reducing associated harm can save lives and improve health.

Examples of harm reduction

Needle exchange programs to prevent HIV/HCV transmission.

- Supervised injection sites.

- Providing naloxone for opioid overdoses.

- Condom distribution to prevent STIs.

Debate about harm reduction

• Supporters: Reduces morbidity and mortality, engages vulnerable populations,cost-effective.

Critics: Some argue it enables risky behaviour or does not address the root cause.

Types of clinical interventions: 

Preventive, Curative/Therapeutic, Palliative, Rehabilitative

Preventive Intervention

1. Prevent disease before it occurs (e.g., vaccines, lifestyle counselling, screening tests).

Curative/Therapeutic intervention

1. Treat existing conditions to cure or manage symptoms (e.g., antibiotics, surgery, chemotherapy).

Palliative Intervention

1. Relieve symptoms and improve quality of life for serious or terminal conditions (e.g., pain management, hospice care).

Rehabilitative Intervention

1. Restore function or reduce disability after illness or injury (e.g., physical therapy, occupational therapy).

Agencies that undertake systematic reviews to propose clinical preventive guidelines

1. USPSTF – United States Preventive Services Task Force

2. Cochrane Collaboration

International organisation of researchers.

3. NICE – National Institute for Health and Care Excellence (UK)

4. WHO – World Health Organization

• Global public health authority.

5. CDC – Centers for Disease Control and Prevention (U.S.)

• Uses evidence reviews to guide public

What are some practical steps that clinicians can take to improve prevention practice?

1. Assess risk factors in patients regularly (e.g., blood pressure, BMI, smoking).

2. Provide education on healthy behaviours and disease prevention.

3. Offer vaccinations and screenings according to guidelines.

4. Use reminders and follow-ups to support adherence.

5. Tailor interventions to patient readiness and context (cultural, social, economic).

6. Collaborate with community resources to support lifestyle changes.

7. Stay updated on evidence-based preventive guidelines and best practices.

How can a clinician diagnose the patient’s change in status and offer “stage-appropriate” support for advancing through the stages? Clinical Stages of Change Model (remember this is just an adaptation of the transtheoretical model)

Diagnose stage, Provide stage-appropriate support

Diagnose stage

Assess patient’s readiness to change by asking about awareness, intentions, and past attempts.

1. Pre-contemplation: Not thinking about change.

2. Contemplation: Considering change.

3. Preparation: Planning to act soon.

4. Action: Actively making changes.

Maintenance: Sustaining changes.

Provide stage-appropriate support:

1. Pre-contemplation: Raise awareness, provide information.

2. Contemplation: Discuss pros and cons, explore motivation.

3. Preparation: Help make concrete plans, set goals.

4. Action: Offer guidance, skills, resources, and encouragement.

5. Maintenance: Support relapse prevention and reinforce successes.

How did public health shift from a focus on infectious disease to chronic disease?

Public health began addressing lifestyle, environmental, and social determinants of health, emphasizing prevention, health promotion, and long-term management rather than just infection control.

As infectious disease rates declined due to better hygiene, vaccines, and antibiotics, chronic diseases (heart disease, cancer, diabetes) became the leading causes of death.

how the causes of death shifted from 1900 to 2013 (review tables in slides

In 1900: People mostly died from infections because there were no antibiotics or vaccines.

Examples:

• Pneumonia

• Tuberculosis

• Diarrhea infections

• Childhood diseases

In 2013: People mostly died from chronic (long-term) diseases because we live longer and survive infections

Examples:

• Heart disease

• Cancer

• Stroke

• Lung disease

• Alzheimer’s

 the top “actual” causes of death

Tobacco

• Smoking and secondhand smoke

• Leads to lung cancer, heart disease, COPD

2. Poor diet + physical inactivity

• Unhealthy eating and not exercising

• Leads to obesity, diabetes, heart disease

3. Alcohol

• Heavy or unsafe drinking

• Causes liver disease, accidents, cancer

4. Microbial agents

• Infections (e.g., flu, pneumonia, COVID-type illnesses)

5. Toxic agents

• Exposure to harmful chemicals or pollutants

6. Motor vehicle crashes

• Driving accidents (speeding, no seatbelt, distracted driving)

7. Firearms

• Suicides and homicides involving guns

8. Sexual behavior

• Unsafe sex → STIs, HIV

9. Illicit drug use

• Overdose, infections, accidents

What are the two big approaches that the government has traditionally taken to promote healthy behaviour?

1. Education:
   - Provides information to encourage healthy choices (e.g., campaigns about smoking risks, nutrition).

- Controversy: Assumes people will change behaviour simply by knowing risks; may not address social, economic, or environmental barriers.

Regulation:

- Laws or rules to shape behaviour (e.g., tobacco taxes, seatbelt laws, bans on trans fats).

- Controversy: Can be seen as limiting per

How can regulation lead to potentially complex outcomes? 

1. May have unintended effects; for example, high tobacco taxes might reduce smoking but increase black-market sales or disproportionately affect low-income populations.

Health Inequality

• Differences in health status or outcomes between individuals or groups. Not necessarily unfair or avoidable. Example: Women live longer than men on average; some genetic diseases affect certain populations.

Health Inequity

• Differences in health that are unfair, avoidable, and socially produced. Example: Higher rates of diabetes in low-income neighborhoods due to poor access to healthy food and healthcare

Health Inequality vs. Health Inequity difference

• Inequality = difference; inequity = unfair, preventable difference caused by social factors.

WHO Determinants

• Social and economic environment (income, education, employment, social support), Physical environment (housing, air/water quality), Personal behaviours and coping skills, Access to healthcare services, Genetic and biological factors

Public Health Agency of Canada Determinants

• Income and social status, Social support networks, Education and literacy, Employment and working conditions, Physical environment, Personal health practices and coping skills, Healthy child development, Biology and genetic endowment, Health services, Gender, Culture

Who did the Whitehall Study examine?

British civil servants in London, both men and women.

What did the Whitehall Study conclude?

Higher job status was linked to better health outcomes; lower-grade employees had worse health.

Why was the Whitehall Study important?

Showed that social determinants, not just healthcare access, affect health; highlighted health inequalities within populations.

How is stress related to working conditions?

• Poor working conditions increase stress, affecting physical and mental health.

How does the physical environment affect health?

air, water, housing, workplaces, and neighborhoods—directly affects health. Poor air quality, unsafe water, overcrowded or damp housing, lack of recreational spaces, and exposure to hazards increase risk of disease and stress.

What is health literacy?

• the ability to access, understand, evaluate, and use health information to make informed decisions about one’s health. It includes understanding instructions, navigating the healthcare system, and applying knowledge to prevent or manage illness effectively.

What is sex?

refers to biological differences such as chromosomes and reproductive anatomy

What is gender ?

socially constructed roles, behaviours, and expectations.

How is sex and gender related to health?

sex affects biological risks, and gender shapes behaviours, access to care, and stress exposure.

How is culture related to health?

• shapes beliefs, norms, and social mechanisms like discrimination or support, which interact with other social determinants to influence outcomes.

Health Belief Model: steps

1. Perceived Susceptibility: How much a person believes they are at risk of a health problem. Example: “I might get the flu this season.”

2. Perceived Severity: How serious a person believes the consequences of the health problem would be.Example: “Getting the flu could make me very sick and miss work.”

3. Perceived Benefits: Belief that a recommended action will reduce risk or severity.
   Example: “Getting the flu shot will prevent me from getting sick.”

4. Perceived Barriers: Perceived obstacles or costs to taking action. Example: “The vaccine is expensive, or I don’t have time to get it.”

1. how socioeconomic disparities affects Canadians vs other countries with different insurance systems

Canada’s public system reduces some barriers, but socioeconomic differences still affect access, especially for services outside the universal plan. Countries relying more on private insurance tend to have bigger gaps in who gets timely, affordable care.

Geographical differences in access to care

• Urban areas: More hospitals, clinics, specialists, and shorter wait times.

• Rural or remote areas: Fewer doctors, longer travel times, limited services, and sometimes long waits.

In Canada: Large rural and northern regions mean many people—especially in Indigenous and remote communities—must travel far for basic or specialized care, leading to delayed treatment.

what are some examples of ways that we can improve access to care for disadvantaged groups in class?

Mobile clinics – bringing doctors, nurses, and basic services directly to underserved neighborhoods or remote areas. Telehealth services – letting people talk to healthcare providers by phone or video, reducing travel barriers.

1. How is SES related to education and health literacy?

People with higher socioeconomic status (SES) usually have more access to good education. Better education leads to higher health literacy

General Five Steps model

1. Pre-contemplation: Not considering change.

2. Contemplation: Aware of the problem, thinking about change.

3. Preparation: Planning to take action soon.

4. Action: Actively making changes.

5. Maintenance: Sustaining the change over time.

Steps in the Clinical Model

• Relapse: Returning to old behaviour; part of the normal process.

• Termination (sometimes included): Complete confidence in sustaining change without risk of relapse.

Application in Public Health:

Tailor interventions to the stage of readiness (e.g., education for pre-contemplation, support for action). Helps design programs that meet people where they are rather than using a one-size-fits-all approach.

Health Belief Model

focuses on perceptions (risk, severity, benefits, barriers) to predict behaviour. Stages of Change focus on readiness and behaviour over time, acknowledging relapse and gradual progress.

Ecological Model of Health

1. Individual: Knowledge, attitudes, skills, biology.

2. Interpersonal: Family, friends, social networks.

3. Organizational/Institutional: Workplaces, schools, healthcare settings.

4. Community: Local norms, relationships among organizations.

5. Policy/Society: Laws, regulations, cultural norms, public policies.

Theory of Planned Behaviour

Attitude, Subjective norms, Perceived behavioural control

Self-Efficacy

Belief in one’s ability to execute actions needed to achieve a goal.

Benefits of self efficacy

Increases likelihood of adopting and maintaining healthy behaviours. Improves coping with challenges or relapse. Enhances persistence and resilience.

What is a causal web?

A diagram mapping multiple interrelated causes of a disease or health outcome. Shows how biological, behavioural, environmental, and social factors interact. Example: For type 2 diabetes: genetics → obesity → diet → socioeconomic status → food environment → policy on sugary drinks.

What is the chain of infection of infectious diseases

Pathogen, Reservoir, Mode of Transmission, Susceptible Host

Pathogen

The microorganism that causes disease. 

Example: Influenza virus, Salmonella.

Reservoir

Where the pathogen lives and multiplies. 

Example: Humans, animals, water, soil.

Mode of Transmission

How the pathogen spreads from the reservoir to a host. Example: Direct contact, droplets, vectors (mosquitoes).

Susceptible Host

An individual who can become infected due to low immunity or other factors. Example: Elderly, immunocompromised, unvaccinated individuals.

How do pathogens constitute a target for intervention

you can stop disease by killing, weakening, or inactivating the germ itself. Example: Using hand sanitizer to destroy influenza virus on hands.

How does reservoir constitute a target for intervention

Removes or isolate intervention. Example: Isolating tuberculosis patients to prevent spread.

How does the mode of transmission constitute a target for intervention?

Block Spread

Intervention: Hand hygiene, condoms, vector control, masks.

Example: Using mosquito nets to prevent malaria.

How does the Susceptible Host constitute a target for intervention?

Make the person less vulnerable to infection, Example: Immunizing children against measles.

What is the goal of contact tracing?

• To identify, notify, and monitor people who have been exposed to an infectious individual in order to prevent further transmission of the disease. It helps contain outbreaks by breaking the chain of infection early.

When was penicillin discovered, by whom, and why is it so important?

• Discovered in 1928 by Alexander Fleming. It is important because it was the first widely effective antibiotic, revolutionizing the treatment of bacterial infections and saving countless lives.

Who was able to first cultivate poliovirus in human tissue?

John Enders, Thomas Weller, and Frederick Robbins in the 1940s.

Who created the first successful vaccine for polio, and when?

Jonas Salk in 1955 (inactivated vaccine).

What are some pervasive threats?

• Widespread or persistent health risks, such as antimicrobial resistance, emerging infectious diseases (e.g., COVID-19, SARS), and vaccine-preventable diseases where coverage is low.

What are the top chronic disease cause of death

• Heart disease, Stroke, Cancer, Chronic respiratory diseases (e.g., COPD), Diabetes

Why is prevention and intervention so much more difficult for Chronic diseases than for infectious diseases?

• they have multiple, interacting causes (behavioural, environmental, genetic), a long latency period, and require sustained lifestyle changes, unlike infectious diseases, which often have a single pathogen and can be controlled with vaccines or treatment.

What are some pervasive threats

• Widespread or persistent health risks, such as antimicrobial resistance, emerging infectious diseases (e.g., COVID-19, SARS), and vaccine-preventable diseases where coverage is low.

significance of the Lalonde Report?

(Canada, 1974) shifted focus from treating illness to health promotion and prevention. It introduced the “health field concept”, emphasizing that health is influenced by biology, environment, lifestyle, and healthcare organization.

Framingham Heart Study

long-term, prospective cohort study started in 1948 in Framingham, Massachusetts, following initially healthy adults to study cardiovascular disease (CVD) development over time.

Why was the Framingham Heart Study Important?

Identified major risk factors for CVD, including high blood pressure, high cholesterol, smoking, obesity, and physical inactivity.

What kind of design was the Framingham Heart Study?

Observational, cohort study—participants are followed over time to see who develops disease. With the major risk factors for cardiovascular disease well established, much of the recent epidemiologic and biomedical research has focused on trying to understand what determines the relative presence or absence of these risk factors.

How is smoking related to cardiovascular disease?

Smoking directly damages your heart and blood vessels, which increases the risk of heart attacks, strokes, and other cardiovascular problems.

What components of tobacco smoke contribute to cardiovascular disease and how?

1. Nicotine: Raises heart rate and blood pressure, increasing cardiac workload.

2. Carbon monoxide: Reduces oxygen delivery to tissues and promotes atherosclerosis.

3. Other chemicals (e.g., oxidants, free radicals): Damage blood vessels, promote inflammation, and increase blood clotting.

4. Overall effect: Accelerates atherosclerosis, increases risk of heart attack and stroke, and worsens overall cardiovascular health.

Developing intervention strategy

Individual-Level: Smoking cessation programs, counselling, nicotine replacement therapy. Lifestyle modification: diet, exercise, weight management, blood pressure control. Community-Level: Public education campaigns about CVD risk factors and smoking harms. Workplace wellness programs promoting healthy behaviours.

What is cancer?

group of diseases where normal cell regulation fails, causing uncontrolled growth, arise when the activities of a cell are transformed, and the cell begins to grow out of control

Ionizing radiation

• Damages DNA directly, causing mutations that can lead to uncontrolled cell growth.

Cancer can occur from ionizing radiation (how?) - viruses

Insert viral genes or disrupt host genes, leading to cancer. Examples: Human papillomavirus (HPV) → cervical cancer; Hepatitis B/C → liver cancer; Epstein-Barr virus → some lymphomas.

common strategies for preventing cancer

Lifestyle changes: Avoid tobacco, limit alcohol, eat a healthy diet, exercise regularly, maintain healthy weight. Vaccination: HPV and Hepatitis B vaccines to prevent virus-related cancers. Screening: Pap smears, mammograms, colonoscopies for early detection. Environmental exposure reduction: Limit UV exposure, reduce workplace carcinogen exposure.

How do governments use either education in the context of cancer prevention?

Public campaigns about smoking risks, healthy behaviours, and screening importance.

How do governments use regulation in the context of cancer prevention?

Tobacco taxes, bans on advertising, workplace safety laws, restrictions on carcinogenic substances.

Type 1 Diabetes

Autoimmune destruction of insulin-producing beta cells in the pancreas; usually develops in childhood or adolescence; requires insulin therapy.

Type 2 Diabetes

Body becomes resistant to insulin and/or produces insufficient insulin; usually develops in adulthood; often linked to obesity, sedentary lifestyle, and genetics; may be managed with lifestyle changes, oral medications, or insulin.

What is the key difference of type 1 and 2 diabetes ?

Type 1 = insulin deficiency, Type 2 = insulin resistance.

How many pairs of chromosomes do humans usually have?

Humans usually have 23 pairs of chromosomes (46 total)

What are autosomes

The first 22 pairs; carry genes for most body traits, not related to sex.

What are sex chromosomes?

• The 23rd pair; determine biological sex (XX = female, XY = male).
  
  

Autosomal dominant

Only one copy of the mutated gene is needed to cause the disease; appears in every generation. Examples: Huntington’s disease, Marfan syndrome.

Autosomal recessive

Two copies of the mutated gene (one from each parent) are needed; may skip generations. Examples: Cystic fibrosis, sickle cell anemia, Tay-Sachs disease.

X-linked diseases: X-linked Diseases

Caused by mutations on the X chromosome; often affect males more severely because they have only one X. Examples: Hemophilia, Duchenne muscular dystrophy.

how do genes interact with the environment

Genes influence responses to the environment, and environmental factors can affect gene expression. For example, genetic risk for obesity may only lead to disease if combined with poor diet and low activity.

Why is knowledge of genes important? Know in the context of human health and disease. 

helps identify disease risk, understand mechanisms of illness, guide prevention, and tailor treatments (personalized medicine). It’s key for managing genetic disorders, predicting chronic disease susceptibility, and developing targeted therapies.

what is Genomic Medicine

• Using information about a person’s genes and genome to guide prevention, diagnosis, and treatment of disease.