Global Health Midterm

Health

“A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity” (WHO Constitution)

Medicine vs. Public Health

Medicine: focus on individuals (and households)

Public Health: focus on populations

Risk Factors

An exposure or characteristic that increases the likelihood of developing a particular disease

Modifiable risk factors

can be addressed through individual & public health initiatives

• behavioral and environmental

• age/genetics

• social networks

• living and working conditions (access to health services)

• broader social, cultural, economic, political, environmental, and policy conditions

Global Health vs. International Health

Global health: transnational health concerns

International health: generally used to refer to health in low-income countries

What is fertility rate

average number of children born to women during their reproductive years

What is mortality rate

the ratio of the number of deaths in the year to the average total population of the year

Demographic Transition Model Stage 1

both birth rates death rates fluctuate at high levels, leading to little or no population growth

Demographic Transition Model Stage 2

advances in sanitation and medicine lead to a rapid decline in the death rate, but birth rates remain high.

Demographic Transition Model Stage 3

processes of modernization lead to declining birth rates.

Demographic Transition Model Stage 4

low birth rates and low death rates mean growth rates remain near zero

ex: US

Demographic Transition Model Stage 5

experiencing negative natural growth

ex: Japan, South Korea

Epidemiologic transition

A shift from a high burden due to infections toward a high burden from chronic, non-communicable diseases (NCDs) that occurs as populations become higher-income economies

• Every population has health concerns, but the mix of main problems changes over time

Major causes of death in the U.S. in 1900

Infectious Disease

– Pneumonia (including influenza)

– Tuberculosis

– Diarrhea

Major causes of death in the U.S. since 1950

Chronic Disease

– Heart disease

– Cancer

– Stroke

Double Burden of Disease

both infectious disease and diseases of affluence

COVID 19 Changing Theory

Globalization and emerging risks of pandemics violate this long-time belief -- all people are at risk of acquiring serious infectious diseases.

We now see that every country is vulnerable to new emerging infectious diseases (e.g. COVID-19), regardless of wealth.

Why do we know health & disease burden metrics?

They provide a foundation for “evidence-based” health policy and practice

- Birth & death rates (vital statistics)

- Mortality

- Morbidity

- Disease burden (including disability)

- Risk factor rates

Demography

the study of the size and composition of human populations

What are the 3 Vital statistics

Birth rates, Death rates, Age-adjusted rates

What are Birth rates

births per year per 1000 people in the total population

What are Death rates

deaths per year per 1000 people in the total population

What are Age-adjusted rates

make different populations with different age structures comparable

Life expectancy at birth

median expected age at death of all babies born alive (which usually includes some child and young adult deaths and many deaths of older adults)

Healthy life expectancy

the number of years the average person born into a population can expect to live without disability

Life expectancy

is a good general indicator of health. Life expectancy is defined as the “average number of years that a newborn is expected to live if current mortality rates continue to apply”

Raw mortality rates

show the number of deaths as a proportion of total population.

Direct age-adjustment

mortality figures are standardized to reflect the population structure of a reference population

crude mortality rate

ignore age, add all deaths and divide my population

Infant mortality rate

is one of the best indicators for the general health conditions of a place.

Incidence Calculation

new cases / susceptible population over a particular time period

new cases of disease

you must have another point to compare new cases vs existing cases with.

Prevalence

proportion of a population with the condition at a particular point in time or a particular time period

total cases of disease

for magnitude of issue of the disease

Burden of disease

an estimate of the impact of disease, disability, and premature death on a population

Disability-adjusted life years (DALY)

a measure of disease burden by adding

years of life lost (YLLs) to premature death + years of life with disability (YLDs)

Quality-adjusted life years (QALY)

a measure of disease burden by multiplying length of life with quality of life (“years lived in perfect health”)

-requires estimating the weight of the burden of various conditions

-better than DALY because QALY takes into consideration quality of life and DALY changes based on disease

Sources of Health Information: Domestic

• Census data

• Vital statistics registries

• Surveillance systems

• Health services (hospital / clinic) records

• Insurance claims

Sources of Health Information: Global

• World Health Organization (WHO)

• Centers for Disease Control and Prevention (CDC)

• National Institutes of Health (NIH)

• Annual reports of United Nations agencies and

specialty health organizations

• Research articles published in peer-reviewed journals

Big Data

Data that is too large or too complex to be managed using traditional data processing, analysis, 5 V’s of Big Dataand storage techniques.

AI may help!

5 V’s of Big Data

(1) Volume: amount of data

(2) Variety: types of data

(3) Velocity: frequency of data

(4) Veracity: quality/trustworthiness of data

(5) Value: not all data is necessarily valuable

observational study

simply observes what people are doing or asks about what they have done in the past. The researchers do not assign any sort of intervention to participants.

cross-sectional study

nothing is known initially about either exposure or disease status. People are sampled at a particular point in time and tested to see if there is an association between an exposure and a health outcome.

case control study

RETROSPECTIVE

people are divided according to their disease status. The exposure histories of the groups are examined and compared for systematic differences that would suggest that a particular exposure is related to the disease.

• STATISTIC USED IS THE ODDS RATIO (OR)

If the OR is ______ than 1, cases were more likely than controls to have the exposure, which implies that the exposure was risky.

greater

Equation using a,b,c,d w/Odds Ratio

(a/c)/(b/d)

Standard Error of OR

cohort study

PROSPECTIVE

people are divided into groups according to their exposure status (such as smokers and non-smokers). The two groups are then followed to see if more of one group experiences a health effect.

-RR (relative risk/risk ratio/rate ratio): statistic to compare incidences in the exposed/unexposed

If the RR is greater than 1, the exposure was/was not? a risk factor for the disease.

was

Relative Risk/Risk Ratio VS. Rate Ratio

Relative Risk/Risk Ratio: final outcome

Rate Ratio: total time to event

RR relative risk/risk ratio/rate ratio EQUATION w a,b,c,d

clinical (experimental) study

after randomly assigning people to two groups, half are exposed to the exposure under study. systematic differences between the two groups suggest the exposure may have had an effect.

CAUSATION

Survey or Interview

Surveys, Focus groups, personal interviews

– An efficient means of gathering data which answers directly the research question

– High cost, long time

Case Studies

– Focus is on individual or small group

– Able to conduct a comprehensive analysis from a comparison of cases

– Could generate an interesting observation of the case

– Depth rather than breadth

– Not necessarily representative

– Depends on data availability

Comparative Studies

– Usually, use cross-sectional data

– Compare same variable(s) in different societies/countries.

– Could generate an innovative finding by simply comparing the conventional aspects.

– Comparability of data is a major issue.

– Missing data may also be a problem.

Ecological Studies

uses aggregated data, such as data for a province or county.

“ecological fallacy”

assume what is true for a population is true for the individual members of that population.

Ecological Fallacy is a situation that can occur when a researcher or analyst makes an inference about an individual based on aggregate data for a group.

aggregation vs disaggregation

Aggregate data combines and summarizes information, whereas disaggregate data separate aggregated data into separate points or pieces of information.

Spatial Approaches

explicitly investigate the importance of spatial attributes such as location and connectivity.

Systematic reviews

systematically search published articles and reports in order to paint a comprehensive picture about everything that is known about a narrow topic of interest.

meta-analysis

pools the results from several independent studies to create a summary statistical measure.

in order to find somehing new!

2 types of meta analysis

1. systematic literature review

2. meta-regression analysis

systematic literature review

is performed to synthesize information from a collection of published studies and identify a range of potential outcomes and key factors that are different among these studies.

meta-regression analysis

technique is used to synthesize and statistically analyze the results while controlling differences across the included studies.

Statistical models / Forecasting

can be used to estimate disease rates in populations lacking good data and to project future health trends.

Prediction/forecasting always brings uncertainty.

Weakness of Meta-analysis

Difficult to capture qualitative distinctions between studies (often ignored)

Socioeconomic status (SES) = socioeconomic position (SEP):

indicators of a person’s standing in a society based on social, economic, and educational characteristics

Social determinants of health:

SES conditions that influence health status and access to health services

3 Most important Social Determinants of Health:

Occupation (employment status), Education, Socioeconomic Position (income, wealth)

Health inequalities vs. Health inequities

Gross domestic product (GDP)

Gross national income (GNI)

Gross national product (GNP)

^^ are not easily ___________

Purchasing power parity (PPP) is better/worse at comparing multiple countries?

Comparabile

Better

Ethnicity vs Race

Ethnicity: groups people based on cultural heritage, nationality, religion, language, and other factors

Race: superficial categories that group people based on physical attributes like skin color

Area effects (neighborhood effects)

refers specifically to the impact of the social and physical environment on health and wellbeing.

Hazard vs Risk

Hazard: most likely happen

Risk: how likely Hazard is to happen

Child vs. under-5 vs. infant vs. neonatal mortality

Neonatal: if child dies before first 28 days

Infant: if child dies after 28 days and between 1st birthday

Child: If child dies after 1st birthday and before 5th birthday

Diarrhea

an increase in the volume of stool and the frequency of defecation; can quickly cause dehydration and death in young children

Solutions for Diarrhea

Oral rehydration therapy/salts (ORT/ORS): a combination of clean water and sugar/salt that rehydrates children with diarrhea and restores electrolyte balance

Malaria

Malaria is a parasitic infection spread by the bites of infected mosquitoes

Pneumonia

occurs when part of a lung fills with fluid, restricting the efficient intake of oxygen

– Many cases of pneumonia can be prevented with vaccines (pneumococcus and Hib)

Under-nutrition recommendations:

Exclusive breastfeeding

Global Hunger Index (GHI):

estimates the burden from undernutrition in a population, with a focus on young children

Health Risks for Young Adults

– Injuries

– Mental health

– Infectious disease (HIV)

The percentage of all deaths that are caused by self-harm is highest in younger adults (do more female or males?)

males

Who are more likely to…

Have lung, bladder, mouth, esophageal, and stomach cancer

Male

Who are more likely to…

Have complications from sexually transmitted infections

Female

Who are more likely to...

Become infected with tropical infections

M, outdoor activities

Who are more likely to...

Die from burns

M injured from fire more, but FEMALES DIE MORE because they cant escape from burn sight

Who are more likely to...

Die from traffic accidents, poisonings, falls, drowning, violence

M

Who are more likely to...

Have Alzheimer’s and other dementias

F bc they live longer

Who are more likely to...

Commit suicide and have drug-use disorders

M

Who are more likely to...

Have depressive disorder, PTSD, panic disorder, and migraines

F

Who are more likely to...

Die from diabetes

F, both can be affected equally but since F lives longer, they die more from it specially

Who are more likely to...

Be victims of domestic violence

F

Maternal mortality:

death during pregnancy, childbirth, or soon after

Access to ________________ reduces the risk of mortality and disability of women giving birth

trained birth attendants

Gravidity:

total number of pregnancies

Fertility:

total number of births (live births plus stillbirths)

Parity:

total number of live births

Replacement population

each woman has, on average, 2 children

Carrying capacity

the maximum human population the Earth can sustain