Contextualizing condoms: a cross-sectional study mapping intersections of locations of sexual contact, partner type, and substance use as contexts for sexual risk behavior among MSM in Peru.

BackgroundCondomless anal intercourse (CAI) appears to be increasing among men who have sex with men (MSM) globally, and is reported to be as high as 70% in recent studies in Peru. To improve understanding of the evolving context of CAI among MSM in Peru, we studied associations between partner type, substance use, and condomless anal intercourse (CAI) in locations where MSM commonly report having sexual encounters.MethodsIn a 2017 cross-sectional study of rectal STI screening and HIV prevention, a convenience sample of MSM recruited from community venues in Lima completed a survey of demographic characteristics and sexual risk behavior with their three most recent partners. Generalized estimating equations estimated correlations of CAI with location of last sexual contact, participant substance use prior to sex, and negotiation of condom use before or during sex. The network data integration application, Cytoscape, mapped intersections of partner type, sexual orientation, substance use, and CAI by four types of locations where sex occurred: 1) Home, 2) Hotel, 3) Sauna or Internet Cabin, and 4) Public Spaces.ResultsOf 447 MSM (median age 27 years), 76.9% reported CAI with ≥1 of their last three partners. Participants reported sex with casual partners most commonly in homes (64.6%) and hotels (60.4%), and with anonymous partners most often in saunas/Internet cabins (57.5%) and public spaces (52.6%). CAI was less commonly reported in hotels (aPR, 95% CI: 0.85, 0.75-0.97) compared to homes. Participants who used marijuana before sex at home were more likely to report CAI than MSM who did not use marijuana (1.36, 1.01-1.92). Partner alcohol use before sex was associated with CAI in saunas/Internet cabins (3.17, 1.45-6.91) and public spaces (2.65, 1.41-4.98). In the sexual network maps, almost all MSM who used drugs prior to their sexual encounters used drugs with more than one of their last three partners.ConclusionsCAI was common and associated with different risk factors, like partner type and substance use, based on location where sex occurred. Novel combination HIV, STI, and substance use prevention interventions must consider how the social environments of MSM influence condom use and other sexual risk behaviors.Trial registrationClinicalTrials.gov Identifier NCT03010020, January 4, 2017

Sexual health norms and communication patterns within the close social networks of men who have sex with men and transgender women in Lima, Peru: a 2017 cross-sectional study

Abstract Background Social networks, norms, and discussions about sexual health may inform sexual practices, influencing risk of human immunodeficiency virus (HIV) or sexually transmitted infection (STI) acquisition. To better understand social networks of Peruvian men who have sex with men (MSM) and transgender women (trans women), we examined key social network members (SNMs), participant perceptions of these network members’ opinions toward sexual health behaviors, and associations between network member characteristics and condomless anal intercourse (CAI). Methods In a 2017 cross-sectional study, a convenience sample of 565 MSM and trans women with HIV-negative or unknown serostatus was asked to identify three close SNMs; describe discussions about HIV and STI prevention with each; and report perceived opinions of condom use, HIV/STI testing, and partner notification of STIs. Generalized estimating equations evaluated relationships between SNM characteristics, opinions, and discussions and participant-reported CAI. Results Among participants who identified as MSM, 42.3% of key SNMs were perceived to identify as gay. MSM “never” discussed HIV and STI prevention concerns with 42.4% of heterosexual SNMs, but discussed them “at least once weekly” with 16.9 and 16.6% of gay- and bisexual- identifying SNMs, respectively. Among participants who identified as trans women, 28.2% of key SNMs were perceived as heterosexual; 25.9%, as bisexual; 24.7%, as transgender; and 21.2%, as gay. Trans women discussed HIV/STI prevention least with cis-gender heterosexual network members (40.2% “never”) and most with transgender network members (27.1% “at least once weekly”). Participants perceived most of their close social network to be completely in favor of condom use (71.2% MSM SNMs, 61.5% trans women SNMs) and HIV/STI testing (73.1% MSM SNMs, 75.6% trans women SNMs), but described less support for partner STI notification (33.4% MSM SNMs, 37.4% trans women SNMs). Most participants reported CAI with at least one of their past three sexual partners (77.5% MSM, 62.8% trans women). SNM characteristics were not significantly associated with participant-reported frequency of CAI. Conclusions Findings compare social support, perceived social norms, and discussion patterns of Peruvian MSM and trans women, offering insight into social contexts and sexual behaviors. Trial registration The parent study from which this analysis was derived was registered at ClinicalTrials.gov (Identifier: NCT03010020 ) on January 4, 2017

Sexual health norms and communication patterns within the close social networks of men who have sex with men and transgender women in Lima, Peru: a 2017 cross-sectional study.

BackgroundSocial networks, norms, and discussions about sexual health may inform sexual practices, influencing risk of human immunodeficiency virus (HIV) or sexually transmitted infection (STI) acquisition. To better understand social networks of Peruvian men who have sex with men (MSM) and transgender women (trans women), we examined key social network members (SNMs), participant perceptions of these network members' opinions toward sexual health behaviors, and associations between network member characteristics and condomless anal intercourse (CAI).MethodsIn a 2017 cross-sectional study, a convenience sample of 565 MSM and trans women with HIV-negative or unknown serostatus was asked to identify three close SNMs; describe discussions about HIV and STI prevention with each; and report perceived opinions of condom use, HIV/STI testing, and partner notification of STIs. Generalized estimating equations evaluated relationships between SNM characteristics, opinions, and discussions and participant-reported CAI.ResultsAmong participants who identified as MSM, 42.3% of key SNMs were perceived to identify as gay. MSM "never" discussed HIV and STI prevention concerns with 42.4% of heterosexual SNMs, but discussed them "at least once weekly" with 16.9 and 16.6% of gay- and bisexual- identifying SNMs, respectively. Among participants who identified as trans women, 28.2% of key SNMs were perceived as heterosexual; 25.9%, as bisexual; 24.7%, as transgender; and 21.2%, as gay. Trans women discussed HIV/STI prevention least with cis-gender heterosexual network members (40.2% "never") and most with transgender network members (27.1% "at least once weekly"). Participants perceived most of their close social network to be completely in favor of condom use (71.2% MSM SNMs, 61.5% trans women SNMs) and HIV/STI testing (73.1% MSM SNMs, 75.6% trans women SNMs), but described less support for partner STI notification (33.4% MSM SNMs, 37.4% trans women SNMs). Most participants reported CAI with at least one of their past three sexual partners (77.5% MSM, 62.8% trans women). SNM characteristics were not significantly associated with participant-reported frequency of CAI.ConclusionsFindings compare social support, perceived social norms, and discussion patterns of Peruvian MSM and trans women, offering insight into social contexts and sexual behaviors.Trial registrationThe parent study from which this analysis was derived was registered at ClinicalTrials.gov (Identifier: NCT03010020 ) on January 4, 2017

Massive nitrous oxide emissions from the tropical South Pacific Ocean

Nitrous oxide is a potent greenhouse gas and a key compound in stratospheric ozone depletion. In the ocean, nitrous oxide is produced at intermediate depths through nitrification and denitrification, in particular at low oxygen concentrations. Although a third of natural emissions of nitrous oxide to the atmosphere originate from the ocean, considerable uncertainties in the distribution and magnitude of the emissions still exist. Here we present high-resolution surface measurements and vertical profiles of nitrous oxide that include the highest reported nitrous oxide concentrations in marine surface waters, suggesting that there is a hotspot of nitrous oxide emissions in high-productivity upwelling ecosystems along the Peruvian coast. We estimate that off Peru, the extremely high nitrous oxide supersaturations we observed drive a massive efflux of 0.2–0.9 Tg of nitrogen emitted as nitrous oxide per year, equivalent to 5–22% of previous estimates of global marine nitrous oxide emissions. Nutrient and gene abundance data suggest that coupled nitrification–denitrification in the upper oxygen minimum zone and transport of resulting nitrous oxide to the surface by upwelling lead to the high nitrous oxide concentrations. Our estimate of nitrous oxide emissions from the Peruvian coast surpasses values from similar, highly productive areas