Rutgers Principles of Public Health midterm

Chinese

-Yellow river region gave birth to health practices

-21st century B.C.

-Ditches to drain

-Wells to drink

-Boiled water

-Extermination of vermin

-Personal hygiene

-Moderation

-Rabies prevention

-Latrines and sewers

Hebrews

Personal and community responsibility:

Maternal Health

Protection of water supplies and food

Disposal of wastes

Sanitation of campsites

Defined conditions unacceptable to PH

Control of communicable disease

Pork ( lead to trichinosis)

Lepers

Egyptians

Systems for collecting rainwater

Sewage disposal

Personal hygiene and bathing

Burned huts

The code of Hammurabi

First set of laws

282 rules, including: conduct of physicians and barbers

Sale of food

Agriculture

Greeks

Gymnastics, olympics

Individual health and fitness

Most important contribution

Airs, waters and places

Hippocrates, 400 BCE

Romans

Water/sewer networks

Baths

Street cleaning and repair

Hospitals

Dark Ages

Quarantine

Return to religious medicine

Rejection of body

Neglect

Infrastructure

Spread of many communicable diseases ( Leprosy, typhus, plague, cholera, etc)

Pandemics were rampant

Renaissance

Revival of learning

Da Vinci, Michelangelo, Copernicus and Galileo

Magellan, Balboa, Cortez and Columbus

Diseases were disinghited and theories of spread were proposed

London in 1600s

Severe epidemics still existed

Mortality reports published for the first time

Colonial America

Paradise

Early colonies

Smallpox and yellow fever

Average mortality was 29

25% mortality rate

Sanitary Reformers (1800s)

England/Edwin Chadwick

America/Lemuel Shattuck

Commission of Massachuesetts

Plague

Yersinia pestis

Transmission from flea bite

Bubonic- 50-60% fatal

Pneumonic- 100% fatal

Incubation period 1-7 days

Overcrowding

Control - reduce exposure to infected fleas

Yellow Fever

Agent is a virus, Flavivirus

20-50% fatal

Transmission by mosquito bite

Incubation period - 3 to 6 days

Overcrowding, high mosquito populations, poor sanitation

Control through sanitation, eliminate standing water, screen windows and doors

Edward Jenner

performed 1st vaccination against smallpox

John Graunt

Natural and political observations made upon the bills of mortality

Basis for vital statistics and modern epidemiology

Edwin Chadwick

Conditions for workers

Lemuel Shattuck

Study of the health and sanitation problems of Massachusetts

Template for many public health systems in U.S.

Miasma (1850-1880)

Notable events

- First State Health Dept.

- Public health teaching begins

Early health departments

Responded to epidemics

Diseases generated by filth

Attempted to regulate

-Graveyards

-Tanneries

-Slaughterhouses

-Dyers, glue boilers

-Reform

Civil War

-Galvanized national awareness of epidemic disease

-360,000 soldiers died

-U.S.Sanitary commission

-Voluntary organization

-Inspected army camps

-Educated troops

-Nursing care and supplies for wounded

Bacteriology (1880-1910)

Specific organisms

Complete rethinking of control

Laws and programs developed

Water, milk and food protection; insect elimination; sewage disposal

Reduction in deaths

First epidemiological revolution

Changes in the profession

An ideological marker

Once untrained amateurs

Now scientifically - trained professionals

Investments in 3 Areas:

-Hospitals ( hill burton Act)

-Training of health personnel

-Biomedical research ( NIH established )

Health Resources (1910-1960)

WW1 inductees ( 34% rejected)

New hiring and organization

Public health nurses

Investments in 3 Areas:

-Hospitals ( hill burton Act)

-Training of health personnel

-Biomedical research ( NIH established )

Depression Era

-New deal and social security Act ( 1935)

-1934- 541 of 3070 counties had local health services

-1942 - 1,828 counties with FT health officers

Social Engineering (1960-1975)

No parity in health resources

Poor didn't benefit from health programs

Notable Events

-Peace corps and food stamp act ( 1961)

-Civil Rights ACt ( 1964 )

-Medicare and medicaid ( 1965 )

-OSHA ( 1970)

-WIC ( 1972 )

-SDWA ( 1974 )

Problem

Still disparity, Need funding

Health Promotion (1975 to present)

Renewed interest in prevention and promotion

Many government reports issued:

Healthy people, healthy communities 2000

Notable events

-Nationals incentives: Childhood immunization, teen

pregnancy, smoking, nutrition

-Smallpox was declared eradicated

Koch's postulates

bacteriolgoy

Show evidence of causal association

The organism is always found with the disease

The organism is not found with any other disease

The organism isolated from one with disease and inoculated into another healthy host causes the same disease

Factors that affect the health of a community

physical factors

social and cultural factors

Organizational Factor

physical factors

Physical environment (air & water)

Geography, topography & climate (tropics,

waterways)

Neighborhood organization (unity

w/threats)

Industrial conditions (noxious odors)

social and cultural factors

ocioeconomic status (governs

exposures, customs)

Social norms (tobacco, alcohol, drugs

Political factors (regulations, $$)

Economy (extremes of rich & poor)

Organizational Factor

Community coalitions

Diversity of services needed

Tax & non-tax supported

(police, health, VNA, Red Cross)

Ten Greatest Achievements of public health in the 20th Century

-Vaccination ( still challenges with religious expectations and anti vax)

- Motor- vehicle safety ( seatbelts public health intive)

- Safer workplaces ( work hours)

- Control of infectious diseases

- Decline in deaths from coronary heart disease and stroke

- Safer and healthier foods

- Healthier mothers and babies

- Family planning

- Fluoridation of drinking water

- Conization of tobacco use as a health hazard

EPIDEMIOLOGY Everyday uses

Identify causes of disease

Complete clinical picture of disease

Identify new syndromes

Measure efficacy of therapy/prevention

Monitor health of region ( surveillance )

ID high Risk groups

Study trends over time ( predictive)

Epidemiology allows public health workers to tabulate , analyze and interpret statistical facts about health problems

Comparison of data

Compare using frequency & distribution

1. Time

-Annual & seasonal occurrences Even daily or hourly

2. Place

-Geographic variation, urban vs. rural, industrial,

commercial, residential, schools

3. Personal

-Age, race, sex, marital status, SES, lifestyle

Rates Definition

number of events per population at risk

To give groups common deminator

Many different types of rates

Incidence rate

Number of new cases during a specified time

period

# of new events or cases/population at risk x 100

Attack rate

An incidence rate calculated for a specific disease for a specific period of time

# of new cases of disease/population at risk over limited time x 100

Secondary Attack rate

The number of persons who get disease as a

result of contact with a known case

# of exposed getting disease/total # of persons exposed to case x 100

descriptive studies

Concerned with distribution of disease

Inexpensive and less time-consuming

Who,where, and when

Case reports or case series

Cross sectional ( prevalence) studies

Cross-sectional

ID's a population of interest

Surveys members about current diseases and exposures

Quick way to determine whether problem exists that warrants further study

Not useful for establishing cause and effect

Analytic

Focus on determinants of disease by testing hypotheses

Cohort

Case-control

Clinical trials

Case control

Study the histories of a group with disease

( cases) & a group without disease (controls)

Advantages

-Quick and inexpensive

-Good for diseases with long latency

-Good for rare diseases

-Can examine multiple factors

Cons:

-Temporal relationship difficult to establish

-Can't calculate RR

-Prone to Bias, especially recall

Cohort

Study a group of people w/out disease over time

Some have suspect characteristics ( i.e. smokers) and some do not

Are people with the suspect characteristic at greater risk?

Clinical trial

Tests effectiveness of drug or other treatment

Treatment or placebo

Petients are followed

Quality information

Most closely resembles controlled experiment

Useful for studying preventive measures

2x2 table

Two groups are chosen

One with exposure or disease

Other with same characteristics but without disease or exposure

KNOW THE 2X2 Table

Diseased and Exposed A

Exposed and no disease B

Not exposed but yes disease C

Not exposed and not diseased D

A+C , A+ B, C+ D, B+D, N = A+B+C+D

Relative risk

The measure of risk for those exposed compared to those who are not exposed

Most commonly reported result in epidemiology

Odds ratio

Odds of exposure among cases to that among controls

OR=

AD/BC

Chance

The observed association is due to " luck of the draw" or chance

In practice, we generally extrapolate ( make inference)

Larger sample size = less variability in estimate

Measures of statistical significance are used to determine degree to which chance variability may account for results

Selection bias

Occurs when the inclusion of subjects depends in some way on the exposure of interest

More of those who agree to principles

Interview bias

The interviewer elicits the information differentially between study subjects

If interviewer knows disease status and hypothesis, they could question differently

Recall bias

Individuals with particular exposure or adverse healthoutcome are likely to

remember experiences differently

May exaggerate their exposure if they

believe there is a link

Confounding

When an observed association ( or lack of one) is due to mixing of exposure, disease and extraneous factor

Finding an association for the wrong reason

Causation Criteria (Hill's Postulates)

Strength of ASsociation

The exposure is associated with a large increase ( or decrease ) in the risk of disease ( statistically )

John Snow

the Broad Street Pump

father of epidemogloy

Demographic Data

Vital statistics

Socioeconomic indicators

Measures of diversity

Health status data

National health & nutritional studies

MMWR

Disease registries

Behavioral risk data

Patient surveys, alcohol,

smoking surveys

Clinical data

Height weight blood pressure

Laboratory data

Cholesterol, lead,RBC, Wbc

Utilization data

Medicare, Medicaid

Health resources

# of hospital beds, # of doctors

Prevalence Rate

Status of a disease in the population at a point in

time

# of existing cases/population at risk x 1000

Dose Response Relationship

Higher dose of exposure = higher rates of disease

Biologic credibility ( plausibility )

Plausible biological mechanism is available to explain findings

Consistency / Generalizability

Other studies have found the same association

Variety of study methods and populations

Time sequence

Exposure can be shown to occur before disease

Specificity

Exposure is associated with specific disease

Alternate Explanations

Have other options been looked at?

Experiment

Do an experiment and altering variables changes outcome

Coherence

Compatible with existing theory

Factors contributing to disease emergence

Societal Events

-Impoverishment

-Conflict

-Population growth and migration

-Urban decay

Health Care

-Transplant

-Immunosuppressant drugs

-Antibiotics

Environmental change

-Deforestation

-Flood/ drought

-Global warming

-Water ecosystem change

Human behavior

-Sexual behavior

-Drug use, diet, travel

-Recreation

-Daycare

Microbial adaptation

-Virulence

-Drug resistance

Food production

-Globalization of food

-Processing, packaging, and prep

Reasons to study communicable disease

New infections replacing old ones

Ebola, hantavirus, mad cow disease

Reemerging, drug resistant" old" disease

Barometer of community

Sensitive to social conditions, food, housing, sanitation

Knowledge

Theories of disease

Supernatural

God,Gods, spirits

Hippocrates- 4 humors ( bile- black and yellow, blood, phlegm)

Miasma - bad air

Germ Theory - koch's postulate

Disease definition

A harmful departure from normal in individuals or populations

Communicable disease definition

One that can be transmitted from one human to another or from animals to humans and zoonoses

Epidemiologic triangle

Aspects of each component

Agent

Host

Environment

Chain of infection

Pathogen

-The disease - causing agent

Reservoir

-The habit in which an infectious agent normally lives and grows

-Human: anthroponoses, symptomatic, or

asymptomatic Animal: zoones

-Optimum reservoirs

-Moisture

-High temperature

-Nutrients

-Absence of light

Portal of exit

-The path by which an agent leaves the source host

Transmission

Portal or entry

-Respiratory

-Oral

-Skin

-Intravenous

-Gastrointestinal

New host

-Final link is a susceptible host

Modes of transmission

Direct transmission

-Direct contact

-Droplet spread

Indirect transmission

-Airborne

-Vehicle borne

-Vector borne

primary prevention

The forestalling of the onset of illness or injury during the pre-pathogenesis period

Vaccines

May be produced from

-Inactivated microbial materials

-Many require boosters

-Live, attenuated

-Revert to virulent form ?

-Carefully tested and monitored

-Synthetic ( lab-made) materials

Spectrum of disease

The natural history of disease without intervention

Sequence of events from the time of exposure until recovery, disability or death

Incubation

Prodrome

Fastigium

Defervescence

Convalescence

Defection

Pandemic

A widespread epidemic, affecting many countries and sometimes entire globe

All people

Devastating infections of past

1918-1919

1300's and 1600's

Colonial America

Zoonoses

a disease which can be transmitted to humans from animals.

Rabies

Virus in saliva of rabid animal;

by bite

200 cases among 50 million dogs

annually

Lyme disease

Tick - rodent - deer

Erythema migrans

, fatigue,

headache, fever, stiff neck, joint

pain, facial palsy, meningitis

Hantavirus

Urine, feces & saliva

fatigue, fever and muscle aches, especially in the large muscle groups—thighs, hips, back, and sometimes shoulders.

Environment

All other factors that inhibit or exhibit the risks

-Social, cultural, and physical factors

-Geology, climate, food source, air

The Host

Any susceptible organism invaded by an infectious agent

-Age, sex, race

-SES, nutrition

-Physiological state

-Pregnancy, puberty, fatigue

-Immunization status

-Behavior

Agent

The element that must be present in order for the disease to occur

Infectivity

-Ability to invade a host, survive and multiply

Pathogenicity

-Ability to produce clinical illness

Virulence

-Ability to cause serious illness or death

vector-borne transmission

the spread of certain disease due to the bite of a vector

Vehicle-borne transmission

transport of an infectious agent into a susceptible host via any intermediate substance (e.g., fomites or food)

Secondary Prevention

The early diagnosis and prompt treatment of

diseases before the disease becomes advanced

and disability becomes severe

Tertiary Prevention

The retraining, reeducation, and rehabilitation of

the patient who has already incurred disability

herd immunity

Protecting a community against certain diseases by having a high percentage of this community's population immunized

Only applies to diseases communicable person to person

Epidemic

Widely and rapidly spreading disease; more than an outbreak

Acute infections

Lesser developed countires

Around people

Unexpectedly large number of cases of disease

Endemic

Persists within geographical areas

Within people

The amount of a particular disease present in a community

Common globally

Doesn't reflect preferred level

Reproductive health

Social, personal & biological

preparation for the responsibilities

of pregnancy & parenthood

Unintended/teen pregnancy

Significance

Consequences

Many don't pursue education

• 10% aged 15 - 17 graduated high school

• 33% of all teen mothers graduate

• 1.5% will graduate college by age 30

• Employment

• Live in poverty

• Many born with little prenatal care

• Low birth rates

• Many result in abortion

Not just physical & psychological costs

• Social, health & welfare services

($40 billion annually)

• $1.00 spent on family planning saves $5.40 in welfare & medical

costs

Prenatal care

Importance

Care in first trimester and nine or more visits in full-term pregnancy

25% of infants in U.S. are born to mothers with late or no prenatal care

Purposes:

Reduce low birth weight

Early detection

Identifying high risk mothers

Education

Benefits of good prenatal care:

REduces infant mortality

Reduces maternal mortality

REduces low birth weight

$1 spent = $4.25 saved in hospital costs for complications

Maternal mortality

The death while pregnant or within 42 days of

termination

Infant mortality

# of deaths for infants < 1 yr old per 1000 live birthds

Worldwide indicator

In 1900, rate of 100/1,000

In 1960, rate of 26/1,000

Recently, rate of FINISH

Higher rates for

-Late or no prenatal care

-Teen mothers

-9-11 years of education

-Smokers

-Unmarried

-Multiple births

-Infants born preterm

-Infants born at low birth weight

Principles of vaccination

Two types of vaccines

Inactivated

Live attenuated

Diptheria

Pertussis

Mumps

Measles

all diseases drastically stopped or erricated because of vaccines

reproductive health : family

Two or more people related

by birth, marriage or adoption

residing together in a household

Family has changed

• Cohabitation

• Single-parent

• 25% of births to unmarried mothers

• 50% of mothers w/infants work outside home

Family Influencing Health

Increased health risks for infants

and children who are raised in

single-parent families.

• Adverse birth outcomes

• Low birth weights

• Increase of infant mortality

• Children living in poverty