Background:
In recent years, HIV/STI prevalences and associated risk behaviors among men who have sex with men (MSM) have increased in Catalonia.

Objective:
This study aimed to examine possible risk factors for high-risk sexual practices in this population.

Method:
A convenience sample of 868 MSM was recruited in 2006 in different gay venues and through the mailing list of a gay community-based organization. An anonymous and self-administered questionnaire was used which explored risk behaviors in the previous 12 months. Univariate and multivariate logistic regression models were used to examine the variables associated with unprotected anal intercourse with casual male partners (UA-C).

Result:
The mean age was 41, more than half had a high level of education (53.6% university degree) and 20.3% were not from Spain (11.5% from Latin America). Among those who had sex with casual partners (91.7%), the prevalence of UA-C was 28%. In multivariate analysis, the likelihood of UA-C was significantly higher in men who were HIV+ (OR:1.8), used more than 4 drugs before sex (OR:1.8 for 4-6; OR:5.3 for +6), were not from Spain (OR:2.0 for Latin American; OR:1.8 for other immigrants), had more than 20 male sexual partners (OR:1.7) and presented a high level of internalized homophobia (OR:2.6).

Conclusion:
The prevalence of UA-C was moderately high among MSM in Catalonia. Men with internalized homophobia, those who used drugs, those who were HIV+ and those who reported multiple sex partners were more likely to engage in risk behaviors for HIV/STI. Moreover, immigrant MSM are at high risk of being infected or transmitting HIV/STI.

Implications:
HIV/STI prevention programs for MSM in Catalonia should address substance abuse and interventions for HIV+ men, as well as attend to psychosocial factors specific to the gay community. Furthermore, prevention messages should be culturally tailored to reduce risky sex behaviors among immigrant MSM.