[When does old age begin?].
D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D003710:Demography; D005069:Evaluation Studies as Topic; D011153:Population; D011154:Population Characteristics; D012106:Research
Adult; Age Distribution; Age Factors; Aged; Demographic Factors; Evaluation; Evaluation Methodology; Population; Population Characteristics; Population Statistics; Research Methodology
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