A cross-sectional study of injection drug use (IDU) and HIV infection identified
ID: 3330278 • Letter: A
Question
A cross-sectional study of injection drug use (IDU) and HIV infection identified an increased association between IDU and HIV infection as compared to non-IDU. The table below presents their data on this topic:
Injection Drug User
HIV Infected
Yes
No
Yes
45
78
No
19
214
A) The prevalence ratio of HIV infection among IDU relative to non-IDU's is _____?
B)True or false: The prevalence of HIV infection among IDU is equal to the complement of the prevalence of no HIV infection among non-IDU?
C)True or false: The odds ratio of IDU among HIV infected relative to non-HIV infected participants is equal to the odds ratio of HIV infection among IDU relative to non-IDU participants?
D)True or False: Injection drug use and HIV infection are independent events.
Injection Drug User
HIV Infected
Yes
No
Yes
45
78
No
19
214
Explanation / Answer
A) Ratio of HIV infection among IDU = 45/(45+78) = 0.3658537
Ratio of HIV infection among non-IDU's = 19/(19+214) = 0.08154506
So prevalence ratio of HIV infection among IDU relative to non-IDU's = 0.3658537/0.08154506 = 4.486522
B) Prevalence of HIV infection among IDU = 45/(45+78) = 0.3658537
Prevalence of no HIV infection among non-IDU = 214/(214+19) = 0.9184549, Its compliment = 1 - 0.9184549 = 0.0815451
So the answer is False.
C) Ratio of IDU among HIV infected = 45/(45+19) = 0.703125
Ratio of IDU among non HIV infected = 78/(78+214) = 0.2671233
Odds = 0.703125/0.2671233 = 2.632211
Ratio of HIV infection among IDU = 45/(45+78) = 0.3658537
Ratio of HIV infection among non-IDU's = 19/(19+214) = 0.08154506
Odds = 0.3658537/0.08154506 = 4.486522
So answer is False.
D) Seeing the above ratios we can conclude that injection drug use and HIV infection are dependent events.
So answer is False.