Study smarter with Fiveable
Get study guides, practice questions, and cheatsheets for all your subjects. Join 500,000+ students with a 96% pass rate.
The epidemiological transition model is one of the most powerful frameworks for understanding how population health evolves alongside economic and social development. You're being tested on your ability to connect mortality patterns to broader forces like industrialization, urbanization, medical innovation, and globalization—not just memorize which diseases dominated each era. This model shows up repeatedly in questions about demographic change, healthcare systems, and global health disparities.
Each stage reflects a fundamental shift in the cause-of-death structure of a population, driven by changes in living conditions, public health infrastructure, and human behavior. When you encounter an FRQ about disease burden or life expectancy differences between countries, the epidemiological transition is your analytical backbone. Don't just memorize the stage names—know what mechanisms drive the shift from one stage to the next and why some populations remain "stuck" in earlier stages while others progress.
The earliest stages of the epidemiological transition are defined by infectious and parasitic diseases as the primary killers, with mortality rates driven by environmental conditions, nutrition, and the absence of medical intervention.
Compare: Stage 1 vs. Stage 2—both feature infectious disease as the primary mortality driver, but Stage 2 shows declining death rates due to public health interventions rather than medical treatment. If an FRQ asks about the role of sanitation versus medicine in mortality decline, Stage 2 is your key example.
As infectious diseases are controlled, non-communicable diseases (NCDs) become the leading causes of death. This shift reflects both success in disease control and new risks introduced by industrialization, lifestyle changes, and extended lifespans.
Compare: Stage 3 vs. Stage 4—both feature chronic disease dominance, but Stage 4 populations delay disease onset rather than just treating it. The key mechanism is preventive intervention (statins, lifestyle modification, cancer screening) rather than acute care. This distinction is critical for questions about healthcare system evolution.
The most recently proposed stage reflects new vulnerabilities created by the very factors that enabled progress: global connectivity, antibiotic overuse, and environmental disruption.
Compare: Stage 1 vs. Stage 5—both feature infectious disease threats, but Stage 5 diseases emerge from modern conditions (globalization, antibiotic resistance, climate change) rather than pre-industrial poverty. Stage 5 populations have advanced healthcare but face novel pathogens their systems weren't designed to handle.
| Concept | Best Examples |
|---|---|
| Infectious disease as primary killer | Stage 1, Stage 2, Stage 5 |
| Chronic/NCD dominance | Stage 3, Stage 4 |
| Public health intervention as driver | Stage 2 (sanitation), Stage 4 (prevention) |
| Lifestyle factors in disease burden | Stage 3, Stage 4 |
| Globalization effects on health | Stage 5 |
| Life expectancy below 50 years | Stage 1, Stage 2 |
| Life expectancy above 70 years | Stage 3, Stage 4, Stage 5 |
| Healthcare system focus on acute care | Stage 1, Stage 2, Stage 3 |
| Healthcare system focus on prevention | Stage 4 |
Which two stages share infectious disease as the dominant mortality cause but differ in whether death rates are rising or falling? What explains the difference?
A country has high rates of heart disease and diabetes but low infant mortality and life expectancy around 72 years. Which stage best describes this population, and what evidence supports your answer?
Compare and contrast Stage 3 and Stage 4: What specific interventions enable the "delay" of degenerative disease onset in Stage 4 populations?
Why might a Stage 5 population be more vulnerable to a novel pandemic than a Stage 2 population, despite having superior healthcare infrastructure?
An FRQ asks you to explain why two countries with similar GDP per capita might be in different epidemiological transition stages. What factors beyond wealth would you discuss?