What do DALYs measure?

• A. DALYs measure quality adjusted life expectancy.
• B. DALYs measure the number of healthy life years gained.
• C. DALYs combine years of life lost and years lived with disability.
• D. DALYs reflect only mortality, not disability.

Answer: (C)

DALYs measure the total burden of disease by combining two components: years of life lost due to premature death and years lived with disability. They add up to give the number of healthy life years lost, reflecting both mortality and morbidity in a single metric. Concretely, one part accounts for deaths occurring earlier than a standard life expectancy (years of life lost), and the other accounts for years lived with disability, adjusted by how severe the disability is (years lived with disability). This makes DALYs a measure of health loss rather than health gain or only mortality. For comparison, quality-adjusted life years (QALYs) focus on years adjusted for quality from a clinical or intervention perspective, not the population-wide burden DALYs track.