This study entailed secondary analysis of data extracted from the Integrated Biological and Behavioural Surveillance Survey (IBBSS) for high-risk groups conducted in 2010 . HIV prevalence and risk behaviour data for young BB and NBB FSWs aged 15–24 years for nine states were analysed.
Eight Nigerian states (Lagos, Kano, Kaduna, Benue, Nasarawa, Edo, Anambra and Cross River) and the Federal Capital Territory (FCT) were selected for the study. To be eligible for recruitment into this study, participants had to be females aged between 15 and 24 years who received money or other valuable gifts/incentives in exchange for sexual favours. A time location sampling (TLS) technique was used to select NBB FSWs. The TLS is a form of cluster sampling that contains both time and location dimensions, it is suitable for obtaining information on hard to reach populations . Working through relevant NGOs and government health staff in different cities/towns, the list of streets, bars, nightclubs and hotels where NBB FSW usually congregate was updated.
The BB FSWs were selected using a two-stage cluster sampling technique. First, a list of brothels where FSW work was drawn and information was collected on the approximate number of FSW present to permit an estimate of cumulative measure of size. Secondly, clusters were selected using probability proportionate to size (PPS) with a fixed number of FSWs recruited from each cluster. The cluster size of the brothel was five and 50 clusters were selected in each state.
Participation in the survey was strictly voluntary and no incentives were provided. To guarantee anonymity, no forms of nominal and biometric identifiers were included in the questionnaires. Informed consent was obtained from each participant. Due to the illegal nature of sex work in the country respondents did not want to sign a consent form. Instead, the interviewer explained the study to the participants and obtained verbal consent for the behavioural and biological components of the study and accompanied the participant to the counsellor-tester for HIV tests. All components of the study received ethical approval from the Nigerian Institute for Medical Research’s (NIMR) Institutional Review Board (IRB) in Nigeria and the Family Health International’s (FHI) Protection of Human Subjects Committee.
The primary independent variable for the study was the FSW typology: BB or NBB FSWs. Other secondary independent variables include:
Highest educational level achieved
Respondents were asked their highest level of education out of seven options—‘never attended school’, ‘Quaranic education’, ‘some primary’, ‘completed primary’, ‘some secondary’, ‘completed secondary education’, and ‘tertiary’ education.
Main reason for going into sex work
Ten possible scenarios based on pre-identified circumstances were used to describe this: ‘financial gain’, ‘unemployment’, ‘pleasure’, ‘marital frustration’, ‘divorced/separated’, ‘widowed’, ‘incest/abused’, ‘others’, ‘don’t know’ and ‘no response’.
Clients and duration of sex work
Clients and duration of sex work was measured using the following: how many customers/clients did you have last day worked, last 7 days how many customers/clients did you have, length of time engaged in sex work in months.
Dependent variables were condom use behaviours of interest and HIV prevalence of both populations. The study assessed participant with the following questions and reported those who responded with ‘yes’ or ‘every time’ to any of the following questions:
Have you had sex with a cohabiting partner within the last 12 months?
The last time you had sex with a cohabiting partner was condom used?
Have you had sex with boyfriend within the past 12 months?
The last time you had sex with boyfriend was a condom used?
Have you had sex with a casual partner within the last 12 months?
The last time you had sex with a casual partner was a condom used?
Within the last 30 days how often did you use condom with your clients?
Do you charge more for sex without condom?
Has a client forced you to have sex without condom?
Are you at risk of HIV infection due to use injectable narcotics?
IBM statistics software SPSS version 20 was used for the extraction and analysis of the data. Descriptive analysis was conducted to characterize the study population of young FSWs (15–24 years). This was followed by bivariate analyses (i.e. Chi square tests and independent samples t test) to examine associations between typology of FSW and selected sexual risk behaviour of the FSWs as well as socio-demographic variables.