The response to Medicare.
D000367:Age Factors; D000368:Aged; D001290:Attitude; D005006:Ethnicity; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008297:Male; D006278:Medicare; D008875:Middle Aged; D012737:Sex Factors; D012922:Social Change; D012923:Social Class; D014481:United States