Global Health Challenges

Why This Matters

Global health challenges aren't just a list of problems happening "somewhere else"—they're interconnected issues that shape health outcomes for billions of people and drive public health policy worldwide. You're being tested on your ability to understand why these challenges persist, how they interact with social determinants of health, and what interventions actually work. The exam expects you to connect concepts like epidemiological transition, health equity, and systems thinking to real-world health crises.

These challenges demonstrate core public health principles: disease burden distribution, social determinants of health, prevention versus treatment approaches, and the role of infrastructure in population health. Don't just memorize that malaria kills people—know why it persists in certain regions, how it connects to poverty and environmental factors, and what distinguishes successful interventions from failed ones. Understanding the underlying mechanisms will serve you far better than memorizing statistics.

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Communicable Disease Threats

Infectious diseases remain the most visible global health challenges because they spread across borders and can rapidly overwhelm health systems. The transmission dynamics of communicable diseases depend on pathogen characteristics, host vulnerability, and environmental conditions—all of which vary dramatically across populations.

HIV/AIDS

• Chronic infection requiring lifelong treatment—unlike acute infections, HIV creates sustained burden on health systems and individuals for decades
• Transmission routes include sexual contact, blood exposure, and mother-to-child transmission, making prevention strategies multi-faceted
• Antiretroviral therapy (ART) has transformed HIV from a death sentence to a manageable condition, but access disparities persist globally

Malaria

• Vector-borne transmission through Anopheles mosquitoes makes environmental conditions and climate patterns critical determinants
• Preventable and treatable with interventions like insecticide-treated bed nets, yet causes over 600,000 deaths annually, mostly in children under 5
• Endemic regions overlap heavily with poverty, creating a cycle where disease burden limits economic development

Tuberculosis

• Airborne transmission makes TB particularly dangerous in crowded, poorly ventilated settings—prisons, urban slums, healthcare facilities
• Latent TB infection affects roughly one-quarter of the global population, with reactivation risk highest among immunocompromised individuals
• Drug-resistant strains (MDR-TB, XDR-TB) represent a growing threat, requiring longer, more expensive, and more toxic treatment regimens

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The Epidemiological Transition: Non-Communicable Diseases

As countries develop economically and life expectancy increases, the disease burden shifts from infectious to chronic conditions. This epidemiological transition reflects changes in lifestyle, diet, urbanization, and aging populations—and it's happening faster in low- and middle-income countries than health systems can adapt.

Cardiovascular Diseases

• Leading cause of death globally—responsible for approximately 18 million deaths annually, more than any infectious disease
• Modifiable risk factors include hypertension, tobacco use, physical inactivity, and unhealthy diet, making primary prevention highly effective
• Health system burden is enormous because CVD requires chronic management, expensive interventions, and long-term medication adherence

Diabetes

• Type 2 diabetes accounts for 90-95% of cases and is strongly linked to obesity and lifestyle factors, making it largely preventable
• Complications include cardiovascular disease, kidney failure, blindness, and amputation—creating cascading healthcare costs
• Rising prevalence in LMICs challenges health systems designed for acute care, not chronic disease management

Cancer

• Second leading cause of death globally—with incidence expected to rise as populations age and adopt Western lifestyles
• Prevention potential is significant: tobacco cessation, vaccination (HPV, Hepatitis B), and screening programs can prevent or catch cancers early
• Treatment access disparities mean survival rates vary dramatically between high-income and low-income countries for the same cancers

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Vulnerable Population Health

Certain populations face heightened health risks due to biological vulnerability, life stage, or systematic marginalization. Targeting interventions toward these groups yields the greatest population-level health improvements—a core public health principle.

Maternal Health

• Maternal mortality ratio (MMR) is a key indicator of health system strength—99% of maternal deaths occur in developing countries
• Three delays model explains most maternal deaths: delay in deciding to seek care, delay in reaching care, and delay in receiving adequate care
• Skilled birth attendance and access to emergency obstetric care are the most effective interventions for reducing maternal mortality

Child Health

• Under-5 mortality has declined dramatically but remains concentrated in sub-Saharan Africa and South Asia
• Leading causes—pneumonia, diarrhea, malaria, and neonatal complications—are largely preventable with existing interventions
• Immunization programs represent one of public health's greatest successes, preventing millions of child deaths annually

Mental Health

• Treatment gap is enormous: in low-income countries, over 90% of people with mental disorders receive no treatment
• Stigma creates barriers beyond access, preventing people from seeking help and reducing funding for mental health services
• Integration into primary care is the recommended approach for expanding mental health services in resource-limited settings

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Environmental and Structural Determinants

Health outcomes depend heavily on the physical and social environments where people live. These upstream determinants often explain more variation in health than healthcare access alone—a fundamental insight of public health.

Water, Sanitation, and Hygiene (WASH)

• Waterborne diseases like cholera, typhoid, and dysentery kill hundreds of thousands annually, almost entirely in areas lacking safe water
• Sanitation infrastructure prevents fecal-oral transmission and is foundational for controlling diarrheal diseases
• Behavior change through handwashing promotion is one of the most cost-effective public health interventions available

Malnutrition and Food Security

• Double burden of malnutrition—undernutrition and obesity coexisting, sometimes within the same household or individual over time
• Stunting (chronic undernutrition in children) affects cognitive development permanently, with lifelong economic consequences
• Food security requires availability, access, utilization, and stability—addressing hunger requires more than just producing enough food

Climate Change and Environmental Health

• Direct health impacts include heat-related mortality, injuries from extreme weather events, and respiratory effects from air pollution
• Indirect impacts through changing disease vectors, food insecurity, water scarcity, and population displacement may be even larger
• Health co-benefits of climate mitigation—cleaner air, active transportation, healthier diets—strengthen the case for climate action

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Health Systems and Global Governance

Individual health challenges cannot be addressed without functional systems to deliver interventions and coordinate responses. Health systems strengthening and global health governance are cross-cutting issues that affect every other challenge on this list.

Healthcare Access and Equity

• Universal health coverage (UHC) means all people receive needed services without financial hardship—a goal, not yet a reality, for most countries
• Barriers to access include cost, distance, discrimination, and lack of trained providers—each requiring different solutions
• Health equity focuses on eliminating avoidable, unfair differences in health outcomes between population groups

Antimicrobial Resistance

• Post-antibiotic era threatens to make common infections deadly again, reversing a century of medical progress
• One Health approach recognizes that AMR develops across human, animal, and environmental sectors and requires coordinated response
• Stewardship programs aim to preserve antibiotic effectiveness through appropriate prescribing and reduced agricultural use

Pandemic Preparedness and Global Health Security

• International Health Regulations (IHR) require countries to detect, report, and respond to public health emergencies of international concern
• Core capacities—surveillance, laboratory systems, workforce, emergency response—determine how quickly outbreaks are contained
• COVID-19 lessons revealed critical gaps in preparedness, supply chains, health communication, and international coordination

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Quick Reference Table

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Self-Check Questions

1. Which two global health challenges share the most common risk factors, and what lifestyle modifications address both?

2. Compare and contrast the epidemiological transition in high-income versus low-income countries—how does the "double burden of disease" manifest differently?

3. If an FRQ asks you to explain why maternal mortality rates vary so dramatically between countries, which three factors would you prioritize and why?

4. How do antimicrobial resistance and pandemic preparedness both illustrate the concept that "a health threat anywhere is a health threat everywhere"?

5. Identify two global health challenges where the primary intervention is outside the healthcare sector—what does this reveal about the limitations of medical care alone?