The Disability-Adjusted Life Year (DALY) is a composite health metric. Which formula CORRECTLY defines it?

• A DALY = YLL (years of life lost due to premature mortality) − YLD (years lived with disability)
• B DALY = (Life expectancy) − (Healthy life expectancy)
• C DALY = YLD × disability weight / incidence
• D DALY = YLL + YLD ✓

Explanation

DALY = YLL + YLD, where YLL captures premature mortality and YLD captures morbidity weighted by disability severity (disability weight 0–1). One DALY = one year of healthy life lost. HALE (Healthy Adjusted Life Expectancy) = life expectancy minus years lived with disability, which is a different metric. Options A, C, and D misapply the components of the DALY formula.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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