title: Incident risk factors as predictors of HIV seroconversion in the Lisbon cohort of men who have sex with men: first results, 2011-2014.
abstract: HIV incidence in men who have sex with men (MSM) is increasing in western countries, including Portugal. We aimed to estimate HIV incidence and to assess how individual short-term changes in exposures over time predict seroconversion. We evaluated participants of an open cohort of HIV-negative MSM enrolled after testing at a community-based voluntary HIV counselling and testing centre in Lisbon. At each evaluation a structured questionnaire was completed and HIV status was ascertained using rapid followed by confirmatory testing. Between April 2011 and February 2014, 804 MSM were followed for a total of 893 person-years. Predictors of HIV seroconversion were identified using Poisson generalised linear regression. The overall seroincidence was 2.80/100 person-years (95% confidence interval: 1.89-4.14). Men who seroconverted had a higher mean number of tests per year. Seroconversions were significantly associated with partner disclosure of HIV status during follow-up, newly-adopted unprotected anal intercourse (UAI) with a steady partner and being newly-diagnosed with syphilis during follow-up. Likewise, sexual intercourse with HIV-positive men, having an HIV-positive steady partner at least once during follow-up and persistent UAI with occasional partners were predictors of seroconversion. High HIV incidence in this cohort is likely driven by short-term contextual and behavioural changes during follow-up.
authors.affiliation: EPIUnit, Institute of Public Health, University of Porto, Porto, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Meireles
authors.forename: R
authors.initials: R
authors.lastname: Lucas
authors.forename: C
authors.initials: C
authors.lastname: Carvalho
authors.forename: R
authors.initials: R
authors.lastname: Fuertes
authors.forename: J
authors.initials: J
authors.lastname: Brito
authors.forename: M J
authors.initials: MJ
authors.lastname: Campos
authors.forename: L
authors.initials: L
authors.lastname: Mendão
authors.forename: H
authors.initials: H
authors.lastname: Barros
mesh_terms: D000328:Adult; D015658:HIV Infections / Q000453:epidemiology*; D015528:HIV Seroprevalence; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D011174:Portugal / Q000453:epidemiology; D012307:Risk Factors; D000069078:Seroconversion; D047568:Unsafe Sex / Q000706:statistics & numerical data