Global Patterns of Disease – Key Notes

Global Burden of Disease: Mortality and Causes

In 2019, global mortality by category shows dominance of non-communicable diseases: 73.6\%; communicable diseases 8.0\%; injuries 6\%.
Leading global causes (2000 vs 2019): Ischaemic heart disease and stroke remain top, followed by COPD and lower respiratory infections; neonatal and maternal conditions contribute significantly in earlier years but are still important in rankings.
Health estimates source: WHO Global Health Estimates (2000–2016) for cause-specific deaths; data show the shift toward non-communicable diseases over time.

Demographic Transition: changes in birth and death rates over time, driving population growth and aging.
Epidemiological Transition: shift in disease patterns from predominantly communicable diseases to non-communicable diseases.
The two transitions occur together and shape population health trajectories.

Births and deaths (per 1000 per year) exhibit four phases:
- Phase 1 (Preindustrial): High birth and death rates.
- Phase 2 (Transitional): Death rates fall while birth rates remain high, rapid population growth begins.
- Phase 3 (Transitional): Birth rates begin to fall, growth continues but slows.
- Phase 4 (Industrial): Low birth and death rates; population stabilizes or grows slowly.
This pattern underpins the demographic transition observed in many countries.

World population growth: initially slow, then rapid with industrialization and modernization.
Global life expectancy at birth has increased substantially over 2 centuries, rising from around the late 19th/early 20th century levels to current higher levels (varies by country and income level).
Gapminder visualizations illustrate wide global differences in population growth and life expectancy by income level and region over time.

Concept: over time, incidence and mortality shift from communicable diseases to non-communicable diseases as primary health challenges.
Implication: health systems adapt from infectious disease control to chronic disease prevention, management, and healthy ageing strategies.

Ageing populations are expanding globally due to declines in fertility and mortality and increasing life expectancy.
Healthy ageing focuses on delaying morbidity and maintaining function to reduce the burden of disability in older age.
Compression of morbidity aims to shorten the period between onset of disability and death, preserving quality of life.
Older adults can be resources for families, communities, and economies when health is supported.

Significance of ageing: sustained increases in life expectancy reshape demand for health and social care, pensions, and workforce participation.
Predictions indicate a rising number of people aged 90+ in many countries, including New Zealand, highlighting needs for age-friendly systems.

New Zealand: population ageing with projections showing substantial growth in the 90+ cohort during the 21st century.
Planning needs include elderly care, chronic disease management, and supportive community infrastructure.

Compression of morbidity policy goal: elongate healthspan, reduce severe disability, and promote independence in later life.
Healthy older populations contribute to families and economies, aligning with global ageing priorities.

Disease patterns have shifted from communicable to non-communicable (epidemiological transition).
Populations have grown and aged (demographic transition); life expectancy is increasing.
DALYs quantify population health loss by combining years of life lost and years lived with disability (DALY = YLL + YLD).
Preparing for healthier ageing is essential to maximize quality of life and societal contributions as age structure changes.