Universe
A description of the population covered by the data in the file; the group of persons or other elements that are the object of the study and to which the study results refer. Age, nationality, and residence commonly help to delineate a given universe, but any of a number of factors may be involved, such as age limits, sex, marital status, race, ethnic group, etc. The universe may consist of elements other than persons, such as specimen, sample or isolate. In general, it should be possible to tell from the description of the universe whether a given individual or element (hypothetical or real) is a member of the population under study. Also known as universe of interest, population of interest, and target population.
Study setting:
The demographic surveillance area of the Somkhele site of the Africa Health Research Institute (AHRI) (previously known as the Africa Centre for Health and Population Studies) was the study setting.
Study population and recruitment of participants:
In WOPS Wave 3, we surveyed all participants who were seen during Wave I and Wave 2 who were still living. For those who have died, we obtained information on mortality from the next of kin or relatives. Additional participants were recruited randomly until an overall sample size of 600 was achieved. We tried to ensure that we attempt to recruit replacements who are both infected and affected by HIV to retain the mix of different types of experience of HIV within the cohort. This resulted in 803 HIV positive and negative participants eventually being enrolled into the cohort.
Study groups:
At initial recruitment, WOPS (Wave 1 and 2), study participants were equally divided into five study groups
The five study groups include:
1. Older people who were HIV-infected but not yet on ART
2. Older people who were HIV-infected and on ART
3. Older people who had a child living with HIV
4. Older people who had a child who died of AIDS-related illness
5. Older people who were not HIV infected, had no known adult HIV infection in the family and had not lost an adult child due to HIV.
This balance of experience of living with/without HIV/AIDS and/or caring for someone with HIV/AIDS will be maintained for Wave 3, with replacements for people who have died or moved away for each group.