Lecture 1: Intro to studying diseases of ph significance

ph bio

• understanding the biological mechanisms of disease

• applies biological knowledge at the pop. level

• biology → explains how disease works

• ph → uses that knowledge to prevent disease & protect populations

how bio helps ph

• explains how disease develops

  • viral replication

  • genetic mutations

  • immune responses

• explains how body responds to

  • enviro exposures

  • behaviors

  • treatments

• identifies pops that may be biologically vulnerable

  • age

  • genetics

  • comorbidities

HIV as an ex of ph bio

• bio → understanding how HIV attacks immune system

• led to development of antiretroviral therapy

• ph uses knowledge to promote:

  • HIV testing

  • prevention such as PrEP

  • access to treatment

how ph guides bio research

• identifies emerging health threats

• creates demand for:

  • vaccines

  • diagnostics

  • treatments

• implements pop-level interventions based on biological evidence

zika as an ex of ph bio

• ph surveillance → identified zika outbreaks

• prompted research into:

  • effects on fetal development

  • mosquito transmission

• biological findings → informed prevention & protection

ph

• measures used to:

  • prevent disease

  • promote health

  • prolong life

• focuses primarily on populations

• can range from small communities → entire countries

• differs from treating 1 individual patient at a time

ph approach

1. surveillance → what’s the prob?

2. risk factor identification → what is the cause?

3. intervention evaluation → what works?

4. implementation → how’d you do it?

big idea: problem → understand it → identify causes → determine what works → implement a response

epi

• helps discover agent, host, & enviro factors affecting health

• determines relative importance of causes of:

  • illness

  • disability

  • death

• identify pops. at greatest risk

• evaluate whether health programs/services actually improve pop. health

think: who is getting sick, why, & whether our interventions work

major ph probs

• non communicable/communicable diseases

• enviro pollution

• maternal & child health probs

• geriatric health probs.

• malnutrition

• pop. probs

major categories of disease in ph bio

• infectious diseases

• degenerative diseases

• genetic & congenital disorders

• nutritional & metabolic disorders

• enviro & occupational diseases

• mental & behavioral disorders

• inflammatory diseases

• emerging infectious diseases

big pic: ph bio studying underlying both communicable & chronic/noncommunicable diseases

“smart pathogens”

• adapt to the host/mutate

• categorized as: commensals or mutuals

• listed as “not parasites”

• exs:

  • HIV/AIDS

  • smallpox

  • measles

“dumb” pathogens

• don’t adapt/mutate

• exs:

  • bubonic plague

  • ebola

  • MRSA

top 3 causes of death in US in 2024

1. heart disease

2. cancer

3. unintentional injuries

major causes of death in US

• heart disease

• cancer

• unintentional injuries

• stroke

• diabetes

2024: suicide replaced covid as 10th leading cause

US mortality trends 2023-2024

• life expectancy ↑ to 79.0 yrs

  • ↑ 0.6 yrs from 2023

• age adjusted death rate ↓ 3.8%

  • 750.5 → 722 deaths/100,000

• infant mortality → no significant change

max lifespan

longest possible duration a member of a species can live under ideal conditions

• humans: ~ 110-122 yrs

• primarily determined by

  • genetics

  • bio

  • biological potential

life expectancy

avg # of yrs. person is expected to live based on when & where they’re born

• influenced by:

  • nutrition & clean H2O

  • sanitation/hygiene

  • healthcare access

  • education

  • vaccines

• pop. level outcome

epidemic/outbreak

disease occurrence in a pop. in excess of what is expected in a given:

• time & place

• think MORE cases than expected

• ex: ebola → cases in parts of africa above what is normally expected

endemic

disease/condition that is present w in a pop. at all times

• think consistently present

• ex: malaria in africa bc it persistently present due to infected mosquitoes

pandemic

disease/condition that spreads across regions

• ex: covid

incidence

#of new diagnosed cases w in a stated period of time

• think NEW CASES

prevalence

TOTAL existing cases in a pop at a stated point in time

• includes existing disease burden rather than only newly occurring cases

• think ALL CURRENT cases

risk

probability that an individual will develop a disease or die w in a stated period

• think probability/chance

rate

#of cases (new or existing) as a fraction of the total pop. at risk

risk factor

• characteristic/exposure associated w an increased likelihood of disease

• helps explain who is more likely to develop an outcome

behavioral risk factors

• tobacco/alc use

• physical activity

• nutrition

environmental risk factors

• air pollution

• UV exposure

• clean H2O

• food access

genetic risk factors

• fam history

• inheritance

• epigenetics

• exposure to radiation/toxins

medical risk factors

• access

• available treatments

sociodemographic risk factors

• education

• income

• age

• sex

• race

• ethnicity

primary prevention

• stop disease B4 it starts

• reduces exposure to risk factors

• goal → prevent disease from starting

• strategies/ex’s:

  • vaccination

  • monitor emerging risks

  • good nutrition

  • clean water/sanitation

think: PREVENT IT

secondary prevention

• early detection of the disease

• disease may be present but asymptomatic

• goal → prevent progression

• strategies/ex’s:

  • screening

  • examinations

  • monitoring

  • mammograms

  • diabetes testing

think: screen/catch early

tertiary prevention

• occurs when symptomatic/existing disease is present

• manages long-term effects

• goal → improve QOL, extend life expectancy

• ex’s:

  • chronic disease monitoring/meds

  • PT

  • pain management

  • prevention of further complications

think: treat/manage existing disease

primordial prevention

• occurs before primary prevention

• prevents risk factors themselves from developing

• focuses on:

  • early life

  • environment

  • societal conditions

disease control

• reducing disease to a desired/acceptable level

• requires continued interventions

• disease still exists

disease elimination

• reduces cases to zero in a particular geographic region

• disease may still exist elsewhere

• continued measures may still be needed

disease eradication

• disease reduced to zero worldwide

• permanent reduction

• example from notes → smallpox

disease mitigation

• minimizes impact of disease

• focuses on:

  • individuals

  • health systems

strengthening health systems

• sometimes best intervention is not eradicating one disease

• instead → build a health system capable of responding to many diseases

• strategies:

  • early detection/avoidance

  • stronger healthcare systems

  • investment in staffing + local infrastructure

  • integration of PH + clinical care

community engagement

• successful interventions depend on the community they are intended to serve

• build local trust + partnerships

• incorporate community knowledge

• culturally relevant strategies improve:

  • uptake

  • equity

why biological effectiveness alone isn’t enough

• PH interventions must fit real-world conditions

• consider:

  • culture

  • trust

  • accessibility

  • local context

  • cost

  • equity

eradication vs. broader public health investment

• eradication may work for some diseases

• may require significant resources

• broader investments may sometimes create greater impact:

  • sanitation

  • disease control

  • primary health systems

  • community engagement

assessment

• core function of ph

• focuses on understanding pop health probs

• includes:

  • monitoring health

  • diagnosing & investigating health probs/hazards

policy development

• core function of PH

• uses health info to develop ph policies & plans

• includes:

  • informing & educating people

  • mobilizing community partnerships

  • developing policies/plans

assurance

• core function of ph

• makes sure needed health services & protections are available

• includes:

  • enforcing laws/regulations

  • linking people to needed health services

  • assuring competent workforce

  • evaluating health service

antibiotic resistance

• current ph prob w biological & societal contributors

• biological → orgs develop resistance

• societal → antibiotic use contributes to the prob

• makes infection more difficult to treat