Sherriff, Nigel StuartJones, Anna MarieMirandola, MassimoGios, LorenzoMarcus, UlrichLlewellyn, Carrie D.Rosinska, MagdalenaFolch, CintaDias, SóniaToskin, Igor A.Alexiev, IvailoKühlmann-Berenzon, SharonPiedade, João Mário Brás da PiedadeNetwork, Sialon II2019-11-262019-11-2620201741-3842PURE: 15587849PURE UUID: 1c09b25d-7c7b-40d1-b1ca-7b2524e17450PubMed: 31090894WOS: 000544172500010Scopus: 85085535678ORCID: /0000-0001-5085-0685/work/131110269http://hdl.handle.net/10362/88512© The Author(s) 2019. Published by Oxford University Press on behalf of Faculty of Public Health.BACKGROUND: Relationship status is an important factor associated with condomless anal intercourse (CAI) amongst men who have sex with men (MSM). METHODS: A multi-centre bio-behavioural survey with MSM was conducted in 13 European cities (n = 4901) exploring factors associated with CAI via bivariate and multivariate multilevel logistic regression analyses. RESULTS: Likelihood of CAI with casual partners was associated with being 'out' to a majority (AOR = 1.19;95% CI 1,1.42); knowing their HIV status (AOR = 1.86; 95% CI 1.25,2.76); using substances (1-2 AOR = 1.39; 95% CI 1.16,1.63, 2+ AOR = 1.81; 95% CI 1.35,2.42); being older (AOR = 0.98; 95% CI 0.97,0.99); successful sero-communication (AOR = 0.79; 95% CI 0.67,0.94); and, not having a recent HIV test (AOR = 0.78; 95% CI 0.66,0.92). CAI with steady partners was associated with successful sero-communication (AOR = 2.72; 95% CI 2.72,3.66); not having a recent HIV test (AOR = 1.26; 95% CI 1.09,1.46), and; being older (AOR = 0.99; 95% CI 0.98,0.99). CONCLUSIONS: Understandings of partner type and/or relationship status in relation to CAI amongst MSM can potentially play an important role in the development of culturally appropriate HIV/STI prevention and risk-reduction efforts targeting at-risk MSM. Our results speak to the need to consider segmented and tailored public health and health promotion initiatives for MSM with differing CAI behaviours and relationship profiles.398586engHIVMSMRelationshipsRespondent-driven samplingTime-location samplingPublic Health, Environmental and Occupational HealthSDG 3 - Good Health and Well-beingjournal article10.1093/pubmed/fdz052https://www.scopus.com/pages/publications/85085535678