This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Best indicator for disease burden? \nSelect and explain. \nA. DALY, B. QALY, C. Sullivan index, D. Disease severity index', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Disability-adjusted life years (DALY):\n\nDALY is a measure of overall disease burden, expressed as a number of years lost due to ill-health,\xa0disability or early death.\xa0\nOriginally developed by Harvard University for the World Bank in 1990,\xa0the WHO subsequently adopted the method in the year 2000.\xa0\nThe DALY is becoming increasingly common in the ﬁeld of public health and health impact assessment.\xa0\nThe major measure used is disability-adjusted life years (DALYs) which combines:\n- Years of lost life (YLL)\xa0calculated from the number of deaths at each age multiplied by the\xa0expected remaining years of life according to a global standard life expectancy.\n- Years lost to disability (YLD) where the number of incident cases due to injury and illness is multiplied by the average duration of the disease and a weighting factor reﬂecting the severity of the disease on a scale from 0 (perfect health) to 1 (dead).\nIt is calculated by the formula: DALY = YLL + YLD.', 'role': 'assistant'}]