Transcript The Epidemiologic Transitions: Past PUBHLTH 350

Global Health in the News
http://www.dailymail.co.uk/news/article-3245006/Martin-Shkreli-defends-massiveprice-hike-AIDS-drug-claiming-HELPING-need-life-saving-medication-funds-researchnecessary-case-disease-evolves.html
Epidemiologic Transitions: The Past
PUBHLTH 350
Matthew L. Boulton, MD, MPH
September 28, 2015
Outline
•
•
•
•
Classifying history by health
The demographic transition
The nutrition transition
The epidemiologic transition
Omran’s “Ages” of Disease
Social features
Disease features
Age of pestilence
and famine
Through 1650,
traditional clan- and
family-based society
High mortality, young
population, high rates of TB
and smallpox
Age of receding
pandemics
Further
differentiation of
classes but large
family-based
societies in rural
areas
Improved nutrition and
sanitation, occupational
health problems and
accidents rise
Age of
degenerative and
man-made
diseases
Small family sizes,
women have
careers, larger
welfare spending
Chronic disease, mental
illness, pollution become
more important
Omran. Milbank Q. 1971
Some Definitions
• Demography: the study of the size and composition of human populations
• Epidemiology: the study of risk factors that determine the presence or absence of diseases
and disorders (the distribution and determinants of disease)
• Statistics:
– Birth rates: births per year per 1000 people in the total population
– Fertility (fecundity): average number of children born to each woman
• Replacement: number of children needed to keep the population stable (2.1 in the United States)
– Death rates = mortality rates: deaths per year per 1000 people in the total population
– Age-adjusted rates: populations with different age structures can be compared
Jacobsen. Global Health 2nd Ed.
What are the Transitions?
• The demographic transition was first conceptualized to describe changes in
society-specific birth rates and mortality rates over time
• Omran (1971) transferred these ideas to public health
• Transitions are a widely used concept in many fields: demography, medical
anthropology, economics, and public health
• Researchers have articulated several different transitions: focus on the
second transition
Omran. Milbank Q. 1971
First Transition Establishment of agrarian
societies
Second
Transition
Industrialization
Third
Transition
The future?
Demographic Transition
A shift from higher to lower birth and death rates which
occurs as populations or countries move from lower-income
to higher-income economies
Tijuana, Mexico
San Diego, US
Jacobsen. Global Health 2nd Ed.
Demographic benchmarks
High mortality
>30 per 1,000 population
Low mortality
<10 per 1,000 population
High birth rate
>40 per 1,000 population
Low birth rate
<20 per 1,000 population
Omran. Milbank Q. 1971
Pre 2nd Transition
2nd Transition
Post 2nd Transition
High birth rate
High death rate
Stable population
Declining death rate
High birth rate
Increasing population
Reduced birth rate
Reduced death rate
Stable (or decreasing)
population
Population Pyramids
Pre 2nd Transition
During 2nd Transition
Post 2nd Transition
High fertility
High mortality
Declining mortality
High fertility
Reduced fertility
Reduced mortality
Reprinted from U.S. Census Bureau, International Population Reports WP/02, Global Population Profile: 2002. Washington, DC: U.S. Government Printing Office;
2004, p. 35. from Skolnik. Global Health 101.
What decreases fertility?
• Bio-physiologic factors: prolonged lactation, surviving
infants mean the mother won’t quickly have another child
• Socioeconomic factors: the desirability of having many
children decreases as more children survive, availability
of birth control
• Psychological factors: rationale for many children
decreases as more children survive, each child now
provided better health care and education
Omran. Milbank Q. 1971
Nutrition Transition
A shift from challenges with population level under-nutrition
to challenges with over-nutrition which occurs as
populations or countries move from lower-income to higherincome economies
Jacobsen. Global Health 2nd Ed.
Diet after the Nutrition Transition
• Increased consumption of energy dense but nutrient dilute
foods
• Food ≠ high-quality nourishment
• Increased prevalence of overweight
What causes the nutrition transition?
Martorell 2005. http://www.cdc.gov/pcd/issues/2005/jan/04_0100.htm
Epidemiologic Transition
A shift from a high burden of illness and death due to
infectious disease to a high burden of illness and death
from chronic, non-communicable diseases (NCD) which
occurs as populations move from lower income to higherincome economies
All populations and countries have health issues, but the
composition of those issues changes over time
Jacobsen. Global Health 2nd Ed.
Epidemiologic Transitions in the US
in the 20th Century
Pre 2nd Transition
• Leading causes of death in the U.S. in 1900
– Pneumonia (including influenza)
– Tuberculosis
– Diarrhea
Post 2nd Transition
• Leading causes of death in the U.S. since 1950
– Heart disease
– Cancer
– Stroke
Jacobsen. Global Health 2nd Ed.
20th Century Control of Infectious Disease
10 Leading Causes of Death as a Percentage of All Deaths
– United States, 1900
Source: http://www.cdc.gov/mmwr/PDF/wk/mm4829.pdf
10 Leading Causes of Death as a Percentage of All Deaths
– United States, 1997
Source: http://www.cdc.gov/mmwr/PDF/wk/mm4829.pdf
Jacobsen. Global Health 2nd Ed.
Jacobsen. Global Health 2nd Ed.
Which group(s) benefited the most from the
epidemiologic transition?
• Childhood survival increases with fewer epidemics and
increased nutrition and sanitation
• Females generally have better health outcomes than
males, except during late adolescent and young adult
ages
Omran. Milbank Q. 1971
Death rates by age
during 2nd Transition
Omran. Milbank Q. 1971
Improvement in death rate among young
women
Omran. Milbank Q. 1971
Transition models
Classical (Western) model
E.g., Europe and North America
• Gradual transition from high mortality and high fertility to low
fertility
• Occurred over many centuries
• Resulted initially from socioeconomic factors, later sanitation
and medical factors
Accelerated model
E.g., Japan
• Occurred only over several decades
• Resulted from sanitary and medical advances and national
priorities
Contemporary model
E.g., current developing countries
• Rapid changes in past half century
• Result from public health measures and national and
international priorities
Omran. Milbank Q. 1971
Questions of the Day
Do national and international politics play a role in the
epidemiologic transition?
Do you agree with Omran that international medical
packages accelerate the transition in developing countries?