Knowledge, preference, or both: it's hard to tell without the data.
Goodman
E
E
D000328:Adult; D004812:Epidemiologic Methods; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States