Definitions of burden of disease and key epidemiological terms

This slide gives definitions for key epidemiological terms used in studies to quantify the burden of a disease. Term defined are the Burden of disease (BoD), Quality adjusted life years (QALYs), Years of life lost (YLLs), Years lived with disability (YLDs), Disability adjusted life years (DALYs), and Healthy life expectancy, or health-adjusted life expectancy (HALE).^1-3

References:
1. Porta M. A dictionary of epidemiology. Oxford, UK: Oxford University Press, 2008.

2. World Health Organization. Indicator metadata registry list. Available at: https://www.who.int/data/gho/indicator-metadata-registry. Accessed June 2025.

3. Institute For Health Metrics and Evaluation. The global burden of disease: generating evidence, guiding policy. University Of Washington, 2013.