Sampling design and recruitment

Sampling design and recruitment

Each round regarding the IBBSS utilized respondent sampling that is driven to your hidden nature of MSM and therefore permits contrast between and across rounds. Respondent driven sampling (RDS) happens to be described in more detail in past studies 22, 23. Shortly, RDS is a modified chain referral sampling that is non-random of recruitment that adjusts for the non-randomness utilizing a mathematical model that weights each sample recruited 23. Inclusion criteria had been male aged 16 years and above with a brief history of oral and/or anal intimate connection with another guy within the six months before the study. Known MSM, designated as “seeds” began the chain for the recommendation use and network vouchers to recruit their peers to the study. Ten seeds were selected for every circular and seeds were diversified by age, educational status and socioeconomic status. In order to avoid an over-representation of MSM with comparable attributes, vouchers limited by three per recruit was utilized 23, 24. In addition, in order to avoid perform enrollment, only 1 screener had been utilized, only 1 person had been authorized to reimburse MSM that has effectively recruited their peers and just one location ended up being utilized. Each voucher ended up being yielded and redeemable N500 approx. $3 USD being a motivation for participating, with an additional N500 directed at a recruit for every effective extra participant. Total settlement ended up being restricted to a maximum settlement of n2000 approximately $12 USD. Test size for the 2007 IBBSS ended up being approximated according to an thought HIV prevalence of 15%, a design aftereffect of 2.0 and degree of accuracy of 0.05. When it comes to 2010 and 2014 IBBSS, test size had been approximated to identify a 10% vary from the subsequent round.

Data collection

Structured close-ended interviewer administered questionnaires elicited information about socio-demographic faculties, style of intercourse lovers and intimate danger habits. Interviews were carried out in MSM organizations that are friendly in each one of the research states. Transactional sex had been examined both with feminine and male lovers. Kind of rectal intercourse practiced ended up being classified as “insertive penile intercourse” or penile that is“receptive” in past times a few months. HIV danger perception ended up being evaluated by asking MSM “do you might be feeling you are vulnerable to illness with HIV? ” with reaction choices being “yes or no”. Consistent condom use with intimate lovers during transactional and non-transactional intercourse had been evaluated by asking the concerns “how frequently did you or your male partner make use of a condom each time you had sex within the last 6 months? ” while condom usage at final sex ended up being examined because of the concern “the last time you’d anal intercourse did you or your partner make use of a condom? ”. Transactional sex had been evaluated by asking “have you received cash or present in return for sex within the last a few months? ” Written permission had been acquired from all individuals for both behavioural and biological the different parts of the study.

Laboratory testing

Detection of HIV during most of the studies ended up being regularly carried out by quick test utilizing blood that is whole acquired from the little finger prick. On the basis of the nationwide HIV evaluating guideline, a synchronous algorithm of Determine (Alere healthcare, United States Of America) and Unigold (Trinity Biotech, Plc, Bray, Ireland) had been utilized to determine HIV sero-positivity while status of discordant tests ended up being verified by using Stat Pak (Chembio Diagnostic techniques, ny, United States Of America).

Information administration and analysis

Data from each research state had been entered CS that is centrally using Pro 3.2 and 25% of questionnaires underwent double-data entry to make certain information quality. Behavioural and biological information had been connected by research identification that is unique for every single participant. Information from each round had been merged and analyzed utilizing STATA 14.0 (STATA Corporation). Descriptive statistics of demographic, behavioural, and biological factors had been carried out. The Cochran-Armitage Chi Square trend test had been utilized to compare differences when considering categorical factors across various rounds of IBBSS, although the Kruskal-Wallis test had been utilized to compare differences in constant factors across various rounds of IBBSS. To determine associations between HIV and predictor factors (Tables), bivariate regression that is logistic had been carried out with p value ?0•2 designated as the cutoff for addition in multivariate logistic regression models. Factors were retained when they attained a p value ?0•05 within the analysis that is multivariate. The predictor variables had been centered on data from literary works that revealed a connection between your factors and HIV.


Table 1 highlights the sociodemographic information of MSM throughout the three rounds regarding the IBBSS. A complete of 897, 1545 and 3611 MSM had been surveyed in 2007, 2010 and 2014 respectively. Many of the participants had been aged 20–24 years in 2007 (61%) and 2014 (46%), while in 2010, almost half (47%) associated with participants had been 25 years or older. Over 85% associated with respondents had never ever hitched in each round regarding the survey. Most of the participants had finished at the least level that is secondary, and also this had been greatest among participants in 2007 with 63per cent followed closely by participants in 2014 (55%).

Intimate danger Behaviours

The median wide range of insertive anal lovers ended up being constant between 2007 and 2010 with about 50% regarding the participants reporting insertive anal sex (IAS) with at the very least two lovers interquartile range (IQR 1–4) within the last few a few months. For receptive anal sex (RAS), a median of two partners that are sexual reported in 2007 although it ended up being one partner both in 2010 and 2014. Overall, about a 3rd had engaged in transactional intercourse in 2007 (95% self- self- confidence period (CI): 30–36%) and 2014 (32–35%), whilst it had been about two-fifths this season (36–41%). Consistent condom use, whenever intercourse ended up being offered increased steadily from 35% (27–44%) to 79per cent (74–83%) between 2007 and 2014. Likewise, constant condom use within the last half a year ahead of the survey during compensated intimate encounters increased from 35% (30–41%) in 2007 to 61per cent (58–64%) in 2014. For non-commercial lovers, constant condom usage increased from 32per cent (29–36%) in 2007 to 51per cent (49–53%) in 2014. For self-reported experiences of sexually transmitted illness (STI), there clearly was a growth from 7% (5–9%) in 2007 to 15per cent (13–17%) this year and 19per cent (17–20%) in 2014.

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