Fifty percent of MSM in our Tijuana sample reported unprotected anal sex with a male partner in the past year. This finding is consistent with previous research that documents high rates of UAI among MSM in other Latin American countries, including Argentina, Brazil, Peru and Ecuador [
12-
15]. The high prevalence of UAI among MSM in our Tijuana sample suggests that interventions to promote safer sex in this population are urgently needed in this region. We identified four risk factors associated with UAI: illicit drug use before or during sex, frequenting specific venues to meet sex partners, lack of HIV testing, and unemployment.
MSM who patronized adult movie theaters were twice as likely to report UAI with men in the past year compared to men who did not visit this type of venue. Because our survey did not ask participants about the type or frequency of sexual behaviors practiced within specific venues, we cannot conclude that MSM who reported UAI actually engaged in that behavior in adult movie theaters. The latter can only be identified as a venue type where some high-risk men go to meet sex partners. Future studies should gather data on the frequency and type of sexual risk practices that do occur in this type of venue as well as the on characteristics of MSM who patronize adult movie theaters. Previous research with MSM in the U.S. and Australia has found that each type of venue tends to attract men with certain characteristics. For example, Lyons et al. [
16] found that younger men were more likely to report anal sex in “sex on premises” venues compared to older men.
Since movie theaters are public settings, there is a greater likelihood that if men engage in sex there, it may be more difficult for them to practice safer sex or to learn each other’s HIV serostatus. Public settings, especially commercial sex venues, have been associated with multiple sexual contacts and group sex [
17]. Also, the extent to which alcohol and illicit drugs are used before or during visits to adult movie theaters should be evaluated; previous studies have reported that the use of poppers is common in commercial sex environments [
18]. The association between patronization of adult movie theaters and UAI among high-risk MSM in Tijuana suggests that this type of venue could be a target for HIV prevention efforts. HIV prevention messages (on posters and in pamphlets) and free condoms have been shown to be effective in other risk venues associated with sexual activity (e.g., bars/clubs, bathhouses) [
19,
20]. The advertisement of safer-sex counseling programs in theater venues could be another effective prevention strategy. Also, structural interventions including the availability of condom machines and changes to lighting and space could help to reduce the occurrence of risky sex encounters [
17].
MSM who used illicit drugs before or during sex had over two times the odds of having UAI with a man in the past year. Over the past 20

years, the link between the non-injection use of illicit drugs and UAI has been well documented in studies of both HIV-negative [
21,
22] and HIV-positive MSM [
23,
24]. In recent years, specific types of illicit drugs have been identified as increasing the odds of high-risk sex among MSM. Cocaine, methamphetamine, and poppers are the most common substances associated with multiple sex partners and unprotected anal sex [
25,
26]. Studies of MSM in Latin American countries have reported the use of alcohol, marijuana, and cocaine during sexual encounters [
12,
27,
28]. In a study of MSM in Ciudad Juárez, Mendoza-Perez et al. [
29] reported that participants who used illicit drugs or alcohol had the highest probability of having risky sex. In the current sample, the most commonly reported illicit drugs used during sex were marijuana and poppers. Reisen et al. also reported that poppers and marijuana were the drugs most frequently used by a sample of Hispanic MSM in the U.S., possibly because they are readily available and inexpensive [
30]. Overall, our finding suggests the need for targeted drug intervention that educates MSM about the dangers associated with transitioning to “harder” drugs, such as methamphetamine and cocaine, that are known to increase sexual arousal and the probability of high-risk sex. The association between illicit drug use and high-risk sex also suggests that opportunities for drug treatment for MSM in Tijuana should be expanded.
Being tested for HIV in the past year had a protective effect in our sample, as it was associated with less UAI. This finding is contrary to studies of HIV testing among MSM in developed countries, where higher rates of risk behavior have been associated with seeking out HIV/STI testing [
31-
33]. In a study of Hispanic men in South Florida, Fernández et al. found that being MSM, having multiple sex partners, and having had sex with someone who had or was suspected of having a STD were among the risk factors associated with HIV testing in the past 12

months, indicating an association between HIV testing and risk awareness [
34]. Our finding suggests that MSM who engage in risky sex in Tijuana may have limited access to HIV testing, lower risk awareness and appraisal, or both. In one study of MSM in Peru, 70.9% of the sample had never been tested for HIV, and the most frequently cited reasons were fear of a positive test result and lack of information regarding where to get tested [
12]. The challenge for prevention researchers is to increase access to HIV testing, reduce barriers to testing, and convince high-risk MSM to adopt HIV prevention practices that combine consistent use of condoms for anal sex and regular HIV testing. This might be accomplished through more public health messages directed at MSM that promote HIV testing. Another step in the development of health promotion interventions is to identify factors that serve as motivators or barriers to HIV testing among high-risk MSM. In an Australian study, MSM who did not test for HIV were less likely to identify as gay, had fewer gay friends, and spent less time with gay men compared to men who did test for HIV [
35]. HIV testing is important as a method of early detection. Testing can help to curtail the spread of HIV through the promotion of prevention practices. It can also have health benefits for the infected individual through initiation of antiretroviral therapy and promotion of condom use. From another perspective, some MSM in our sample were likely to have had access to HIV testing and prevention messages, and yet engaged in UAI during the past year. As shown in studies conducted in the U.S., high rates of UAI among socially connected MSM may be partially explained by “condom fatigue” and frustration with prevention programs that focus exclusively on condom promotion [
36-
38]. The development of HIV prevention programs that expand upon condom promotion to include other priorities such as communication skills, stress management, coping skills, and broader physical and psychological health issues are warranted.
The rate of unemployment in our sample of MSM was very high (43%) compared to the rate of 7.6% reported for Tijuana in the third quarter of 2011 [
39]. Unemployed MSM were approximately two times more likely to report UAI in the past year compared to their employed counterparts. It is plausible that unemployed men are more likely to engage in commercial sex work, which could involve engaging in UAI. The link between unemployment and UAI could also be explained by insufficient funds to purchase condoms or increases in risky health habits. Indeed, previous research has found an association between unemployment and increased cigarette smoking, illicit drug use, and heavy alcohol consumption [
40]. It is also possible that unemployed men in Tijuana seek work in the U.S. and subsequently become vulnerable to risk behaviors (UAI, injection drug use) associated with cross-border activity [
41]. In the face of a global recession that continues to affect Mexico, it is critical that unemployed MSM in Tijuana be recognized as a vulnerable subgroup that is in urgent need of HIV prevention and intervention.
This study has several limitations. The convenience sample of MSM, which was recruited at a large-scale community event, should not be considered representative of the general population of MSM in Tijuana. In particular, MSM who do not attend gay-oriented public events were not represented in this survey. Non-participants could have differed from volunteers in terms of socio-demographic, psychosocial, and behavioral characteristics. Indeed, there is research to suggest that MSM in Mexico who identify as “heterosexual” are less likely to access HIV resources and are thus in need of targeted prevention efforts [
42]. It is also possible that among the men who did attend the event, those with high-risk behaviors and those reticent about their sexual orientation may have been less likely to participate in the survey, which gathered sensitive personal information. Men who did participate in the survey may have been affected by considerations of social desirability and hence may have underreported the extent of their sexual risk and drug use behaviors. If that be the case, we may have underestimated associations between drug use behaviors and UAI. Also, because of Tijuana’s location along the U.S.–Mexico border, our findings may not be generalizable to MSM in other parts of Mexico that are less influenced by cross-border activities and risk behaviors. The one-year time frame used in this study may also have led to inaccurate or faulty recall. Last, this research used participant self-report to ascertain HIV serostatus. Future studies should use laboratory tests of HIV serostatus to examine the association between HIV serostatus and sexual risk behaviors among MSM.