Each round for the IBBSS utilized respondent sampling that is driven to your concealed nature of MSM and so enables comparison between and across rounds. Respondent driven sampling (RDS) is described at length in past studies 22, 23. Fleetingly, RDS is really a modified chain referral sampling that is non-random of recruitment that adjusts for the non-randomness utilizing a mathematical model that loads each sample recruited 23. Inclusion criteria had been male aged 16 years and above with a brief history of dental and/or anal contact that is sexual another guy when you look at the six months before the study. Known MSM, designated as “seeds” began the chain regarding the recommendation use and network vouchers to recruit their peers to the research. Ten seeds had been chosen for every circular and seeds had been diversified by age, academic status and socioeconomic status. In order to avoid an over-representation of MSM with comparable characteristics, vouchers restricted to three per recruit was utilized 23, 24. In addition, in order to avoid perform enrollment, just one screener had been utilized, only 1 individual had been authorized to reimburse MSM that has successfully recruited his peers and only one location ended up being utilized. Each voucher had been redeemable and yielded N500 approx. $3 USD as a motivation for participating, with an extra N500 provided to a recruit for every effective participant that is additional. Total payment ended up being limited by a maximum settlement of n2000 approximately $12 USD. Test size when it comes to 2007 IBBSS ended up being projected predicated on an thought HIV prevalence of 15%, a design effectation of 2.0 and degree of accuracy of 0.05. For the 2010 and 2014 IBBSS, test size ended up being projected to identify a 10% vary from the subsequent round.

Data collection

Structured close-ended interviewer administered questionnaires elicited information on socio-demographic traits, sort of intercourse lovers and intimate risk habits. Interviews had been carried out in MSM organizations that are friendly in all 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 “receptive penile intercourse” in past times a few months. HIV danger perception ended up being examined by asking MSM you are at risk of infection with HIV? ” with response options being “yes or no”“do you feel. Consistent condom use with intimate lovers during transactional and non-transactional intercourse had been examined by asking the concerns “how often did you or your male partner work with a condom each time you had intercourse within the last 6 months? ” while condom usage at last intercourse had been assessed because of the concern “the last time you'd rectal intercourse did you or your partner make use of a condom? ”. Transactional sex had been evaluated by asking “have you received money or present in return for intercourse within the last few a few months? ” Written consent had been acquired from all participants for both behavioural and biological aspects of the study.

Laboratory testing

Detection of HIV during most of the studies had been regularly done by quick test making use of blood that is whole acquired from a hand prick. In line with the nationwide HIV evaluation guideline, a synchronous algorithm of Determine (Alere healthcare, United States Of America) and Unigold (Trinity Biotech, Plc, Bray, Ireland) had been utilized to recognize HIV sero-positivity while status of discordant tests ended up being verified if you use Stat Pak (Chembio Diagnostic techniques, ny, United States Of America).

Data administration and analysis

Data from each research state had been entered centrally making use of CS professional variation 3.2 and 25% of questionnaires underwent double-data entry to make sure data quality. Behavioural and biological information had been connected by research unique recognition quantity for every single participant. Information from each round were merged and analyzed utilizing STATA 14.0 (STATA Corporation). Descriptive statistics of demographic, behavioural, and biological variables 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 ended up being utilized to compare variations in constant factors across various rounds of IBBSS. To determine associations between HIV and predictor factors (Tables), bivariate logistic regression analysis ended up being 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 multivariate analysis. The predictor factors had been according to information from literary works that revealed a connection amongst the factors and HIV.

Sociodemographics

Table 1 highlights the sociodemographic data of MSM over the three rounds associated with IBBSS. A complete of 897, 1545 and 3611 MSM had been surveyed in 2007, 2010 and 2014 correspondingly. Most participants had been aged 20–24 years in 2007 (61%) and 2014 (46%), whilst in 2010, almost half (47%) of this participants had been 25 years or older. Over 85% associated with participants had never ever hitched in each round regarding the study. Greater part of the participants had finished at the least additional level training, and this ended up being highest among participants in 2007 with 63per cent accompanied 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% associated with the participants insertive that is reporting sex (IAS) with at the least two lovers interquartile range (IQR 1–4) within the last few six months. For receptive anal sex (RAS), a median of two intimate lovers had been reported in 2007 whilst it ended up being one partner both in 2010 and 2014. Overall, about a 3rd had engaged in transactional intercourse in 2007 (95% confidence period (CI): 30–36%) and 2014 (32–35%), although 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 79% (74–83%) between 2007 and 2014. Likewise, constant condom use within days gone by six months before the survey during paid intimate encounters increased from 35% (30–41%) in 2007 to 61per cent (58–64%) in 2014. For non-commercial partners, constant condom usage increased from 32per cent (29–36%) in 2007 to 51percent (49–53%) in 2014. For self-reported experiences of sexually infection that is transmitted, there is a growth from 7% (5–9%) in 2007 to 15per cent (13–17%) this year and 19per cent (17–20%) in 2014.