Public Health Midterm Review

What (Case Definition)

Clinical criteria (the more specific the better)

Who? (Person)

Consider genetics and socioeconomic factors

Where? (Place)

Geographical differences; resident, birth, employment locations

When? (Time)

Secular trends over years and seasonal patterns

Why?

why lol

Epidemiological Triad

Web of Causation

Sufficient Cause and Component Causes Model

Pulmonary

relating to the lungs

John Snow

cholera pump dude

made a ghost map

actually talked to people

Paracelsus

toxicology

dose-response relationship

organ targeting

John Graunt

quantative methods

“Columbus of statistics “

Ramazzini

Occupational medicine

“whats ur job”

Sir Percival Pott

environmental cause of cancer

chimney sweeps —> scrotal cancer

first environmental protection: baths

William Farr

system to code conditions

links mortality rates and population density

Robert Knock

Association between a microorganism and disease

Variolation

Infecting healthy with smallpox through cuts or nose

Edward Jenner

Created vaccinations through cowpox on a dairymaid

Global eradication campaign

US-AID funded campaign to remove smallpox everywhere

Konner and Eaton

Current diets and lifestyles are mismatched to evolutionary environments

Code of ethics includes…

Evidence-based public health, timely dissemination of information, tailoring for diverse audiences

Tuskegee Syphilis Study

1932 600 black men not told some had syphilis, not given cure after development

Vertical transmission

women transferring diseases to their children

Henrietta Lacks

1951 cells doubled every day, harvested and spread without her consent (HeLa cells)

Moore vs Regents of the University of California 1990

HeLa cells are not her property and can be commercialized lol

The Common Rule 1991

enforces informed consent

Etiology

the cause, set of causes, or manner of causation of a disease or condition

deontology

ethics are determined by right or wrongness or individual event consequences

Consequentialist

ethics are determined by individual event consequences

Sufficient cause (SCM)

Set of factors that inevitably cause disease

Component cause (SCM)

Individual factors forming sufficient cause

Necessary cause (SCM)

Component mustb e present for the disease

Stages of disease

Susceptibility, subclinical disease (latency), clinical disease (symptoms), outcome (recovery or death)

[Point] Prevalence

Frequency of existing cases

Number of cases / Total population

Incidence Rate/Density

Frequency of new cases

New cases / Total person-time at risk

Cumulative incidence (Risk)

New cases / Population at risk at start

Odds

Cases / non-cases

Risk Ratio (Relative Risk)

Risk in exposed / Risk in unexposed

[a(a+b)]/[c(c+d)]

Odds Ratio

Odds in exposed / odds in unexposed

(a x d)/(b x c)

[Incidence] Rate Ratio

Incidence rate in exposed / Incidence rate in unexposed

Total person time

Sum of time each subject observed disease-free

Use prevalence when…

Burden of disease at a point in time

Use risk (CI) when…

Probability over a fixed period in closed populations

Use incidence rate when…

dynamic populations, varying follow-up

Use relative risk when…

cohort studies, interpretable as risk reduction/increase

Use odds ratio when…

case-control or rare outcomes

Use incidence rate ratio when…

longitudinal studies with person-time

The ICD system

the international classification of diseases, injuries, and causes of death

published by WHO

Patterns to relationships process

Quantify associations (measures of effect), design studies to test hypotheses, evaluate evidence for causation

The 2×2 Table

Relative Risk = 1

No association between exposure and disease

Relative Risk > 1

Exposure increases disease risk

Relative risk < 1

Exposure decreases disease risk

Odds ratio = 1

No association

Odds ratio > 1

Higher risk of exposure in cases (positive association)

Odds ratio < 1 

Lower odds of exposure in cases (protective association)

Cause of cases 

Why certain people get sick

Cause of incidence

Why populations differ in disease rates

Prevention paradox

A preventative measure which brings much benefit to the population offers little to the individual

ex. wearing seatbelts

High risk strategy

focus on high risk individuals

cost effective generally

costly screening wise

only small percentage of people

Population strategy

Bring down risk of everyone

very expensive

small benefit for each individual

prevention paradox

Public health

The organized effort of society to prevent disease, prolong life, and promote health through population-level interventions

Focus of public health

populations over individuals

prevention over care

Hominid era

Plant-based remedies

Burial practices

Mobility reduced disease spread

Ancient cities

Sanitation

nutrition

crowding

plague, cholera, smallpox

case report

a detailed description of a single patient’s experience

(descriptive)

cross-sectional study

an observational research method that collects data from a population at a single point in time

(descriptive)

Cohort studies

Following a group of people over time

(analytical)

Case-control study

inflicted cases versus controls to determine association with past exposure

(analytical)

Ecological study

Examines relationships between health outcomes and environmental factors that the population level rather than the individual level

(analytical)

Randomized controlled trials (RCTs)

a scientific experiment that uses random assignment to divide participants into different groups to compare the effects of an intervention or treatment

randomization is “gold standard” in experiments

(experimental)

primordial level of prevention

prevent risk factors

ex. urban planning and poverty reduction

primary level of prevention

prevent disease onset

ex. vaccines, sanitation

secondary level of prevention

early detection and treatment

ex. screening programs

tertiary level of prevention

reduce complications, disability, recurrence

ex. rehab

quaternary level of prevention

prevent over diagnosis and medical harm

Wilson & Jugner screening criteria 1968 - definition

10 principles for deciding whether a disease should be included in a population screening program

Wilson & Jugner screening criteria 1968 - requirements

Disease is important, has latent stage, effective treatment exists

Tests must be acceptable, cost-effective, and part of ongoing care

Lead-time bias

Earlier detection does not mean improved outcome

could be same life span anyway

length-time bias

screening detects slow-growing disease, not good for fast

overdiagnosis

Identifying disease that wouldn’t cause harm

APHA code of ethics

prevent disease, respect rights, include community input, address social determinants, evidence-based action

Virtue ethics

compassion, integrity

Kantain ethics

Individuals are ends, not means

Utilitarianism

Greatest good for greatest number

Belmont report

Created in response to public outrage over tuskegee study

established respect for persons, beneficence, and justice

Havasupai case

2004 lawsuit by havasupai tribe against ASU over misuse of blood samples

thought it was only for diabetes but they kept using it

informed consent violations

Infant mortality

Deaths under 1 year / 1,000 live births

Maternal mortality

deaths during pregnancy or postpartum

Leading causes of maternal mortality

mental health, cardiovascular disease, hemorrhage, infection

Reading peer-reviewed articles

identify purpose, understand methods, interpret results, evaluate discussion, check of limitations