Coming crossed from Atlantic Ocean
as the first case was happened in Copenhagen1977 until becoming an outbreak 6305
deaths from 8408 cases in our Country, AIDS is definitely has become silent
killer over the centuries. It killed all people including gay men, intravenous
drug users, even new baby born.  This
disease was totally changed from an ignored hidden disease to its designation
as a public health issue. We should awake to start further disease for this
disease.

A nested case-control study design which
is similar in principle to the case – cohort study will help us to investigate
efficiently to know how this disease was evoluted. Using nested case control
study we will get combine of cost benefits as a case control study with the
advantages of prospective data collection in a cohort study. This type of study
way more suitable for our case, since the outcome still in rare condition and
the exposure still too difficult to be obtained. Nested case control study allowed
us to utilizing data previously collected from cohort study. We can investigate
risk factor retrospectively with the case group that were taken from cohort
member who developed the disease of interest. Meanwhile control group are
selected from cohort members who were AIDS free at the time cases were
diagnosed. Control are matched to the cases for follow up.

This type of study inspired from
series of Nurse’s Health Study I (NHS) in 1976,a study to see all relationship between
risk factors that related to major chronic disease in women (Hankinson et al,.
1997). Using their previous cohort data, by using nested case control study they
can inferred the relation of gene expression with breast cancer incidence. Meanwhile
on the previous study it is not obtained that might be it could be associated. As
the result, they can find another exposure that related to breast cancer.

Compare to another study, such us
case control study, nested case control study is less expensive and in a way more efficient. Recall
and selection bias are something that we can minimize by using this study
(Sedgwick, 2014). Furthermore, in several situations nested case control study have greater statistical
power than cohort studies. Which is when we use a cohort study, a large number
of study populations must be followed to obtain a sufficient association
(Hulley et al., 2001).