Intentional Risk Reduction Practices of Men in Switzerland Who Have Anal Intercourse With Casual Male Partners : JAIDS Journal of Acquired Immune Deficiency Syndromes

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Epidemiology and Prevention

Intentional Risk Reduction Practices of Men in Switzerland Who Have Anal Intercourse With Casual Male Partners

Balthasar, Hugues MA; Jeannin, André MA; Lociciro, Stéphanie PhD; Dubois-Arber, Françoise MD, MSc

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JAIDS Journal of Acquired Immune Deficiency Syndromes 54(5):p 542-547, August 15, 2010. | DOI: 10.1097/QAI.0b013e3181e19a6b
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In the decade after the arrival of effective antiretroviral therapy, most western European countries faced a notable resurgence of the HIV epidemic in men who have sex with men (MSM)1 accompanied by sexually transmitted infection outbreaks that primarily affected HIV-positive MSM.2-4

Continual changes in sexual and preventive behaviors gave rise to these trends.5 Actually, most countries in which an HIV behavioral surveillance system has been established observed an increase in the practice of anal penetration with steady and casual sexual partners6-8 and a decrease in strict adherence to safe sex guidelines,7-11 although in some countries like the United Kingdom or Germany, levels of risky behaviors started to level off.12,13

Beginning early in the epidemic, MSM managed their infection risk by, for example, negotiated safety in the context of a steady relationship.14,15 Although such strategies are manageable with a main partner,15 they are less manageable in the context of casual sexual relationships, a fortiori with anonymous partners. For several years, evidence existed that MSM were likely to adopt protective behavior alternatives to condom use to reduce HIV transmission risk while having unprotected anal intercourse (UAI).8,9 These practices, generically labeled as “risk reduction behaviors,” include practices such as “serosorting” (the process of choosing to have unprotected sex with partners of same HIV status), “strategic positioning” (the HIV-negative partner acts only as the insertive participant during the sex act and the HIV-positive partner acts only as the receptive participant), and withdrawal before ejaculation. Per-contact risk estimations were provided for these practices, and none achieve a level of protection equivalent to condom use.16,17

Evidence of serosorting is reported in many places 2,11,18-22 and would seem to be on the increase in MSM.6,18,23 In some places, serosorting was granted direct or indirect support from prevention activists and/or public health authorities, for example, in San Francisco in 2006 with the “Disclosure Initiative.”24 Since then, however, researchers showed the limits of this approach, arguing that serosorting could potentially increase HIV transmission to the extent that rates of unrecognized and/or acute infection are high in the reference population.25,26 However, a recent prospective cohort study showed that these practices are likely to reduce rates of HIV infection, with strategic positioning appearing to be the most effective practice followed by serosorting and withdrawal.27

Strategic positioning is used by MSM when having unprotected anal sex in the context of serodiscordant relationships and with casual partners.20,28 By analyzing sexual practices, Van de Ven et al found that sexual positioning was more likely to correspond to a risk reduction strategy than a sexual preference.28 Parsons et al20 also identified clear patterns of strategic positioning in HIV-positive MSM, who were more likely to be only receptive with their casual or HIV-negative partners than with a HIV-positive partner, thus showing more concern about possible HIV transmission than about reinfection.

Withdrawal before ejaculation during anal sex may be well accepted in MSM as a harm reduction practice29 although we know that pre-ejaculatory fluid may not be free of the virus.30,31 Behavioral surveys in France showed that 3 of 4 men practiced withdrawal while having UAI with casual partners.6 High prevalences of withdrawal were also reported in the United States, Australia, and Switzerland.20,28,32,33

This observational study focuses on items that explicitly concern risk reduction practices in MSM living in Switzerland who had UAI with casual partners with the objective of intentionally avoiding HIV transmission. The aim of the study is to ascertain the importance of risk reduction practices in the context of the overall protection strategy adopted by MSM having anal intercourse with their casual partners and to identify factors associated with different levels of protection: systematic use of condoms, intentional use of risk reduction practices, and inconsistent condom use without any intentional use of risk reduction practices.


Study Population and Data Collection

Data were collected in 2007 in the context of an HIV behavioral surveillance survey (Gaysurvey; n = 2953), which is part of the Swiss HIV behavioral surveillance system.34,35 The survey has been repeated 8 times between 1987 and 2007. The survey was cross-sectional, relied on a self-selected sample of MSM, and used an anonymous self-administered questionnaire. The items on sexual risk reduction practices were introduced for the first time in the 2007 core questionnaire.

The questionnaire had both a paper-and-pencil and an Internet mode of administration. It was distributed throughout Switzerland through 4 main channels to achieve wide coverage. Paper-and-pencil questionnaires were printed in the 5 prominent, Swiss, gay newspapers of which 4 are largely distributed as free publications in gay venues. Questionnaires were also sent by almost all gay organizations to their male members or supporters by postal mail and distributed in most gay bathhouses with the support of their umbrella organizations. Participants had to return the completed paper questionnaire by postal mail. The online questionnaire was advertised through banners published on 10 prominent gay Web sites within the “.ch” Internet domain, including the international instant messaging platform, GayRomeo. Both the paper questionnaire and the Internet questionnaire were available in German and French. The data were collected between June and October 2007.

The questionnaire was reviewed by the Swiss Federal Office of Public Health, the Swiss AIDS Foundation, and gay community leaders. The survey was approved by the ethical review board of the Faculty of Medicine and Biology at Lausanne University, Switzerland.


The questionnaire provided self-reported information on sociodemographic characteristics, sexual activity, HIV status (self-reported), sexually transmitted infection history, and preventive behaviors in the last 12 months in different relationship contexts (casual/steady partners and partners with different or unknown HIV status). The use of sexual risk reduction practices was assessed with 3 questions (1 per practice), each referring to UAI with casual partners and stressing the participant's purposeful decision to reduce HIV transmission risks in such circumstances:

  1. Serosorting: “Over the past 12 months, did you ever practice anal penetration without a condom and ask your partner if he was of the same HIV status as you, in order to avoid HIV infection? (with casual partners: yes/no).”
  2. Strategic positioning: “Over the past 12 months, did you ever practice anal penetration without a condom and choose only the insertive or receptive role in order to avoid HIV infection? (with casual partners: yes, only receptive/yes, only active/no).”
  3. Withdrawal before ejaculation: “Over the past 12 months, did you ever practice anal penetration without a condom and withdraw before ejaculation in order to avoid HIV infection? (with casual partners: yes/no).”

A casual partner was defined in the questionnaire as any sexual partner that the participant did not consider to be his steady partner. The label for each practice did not appear in the questionnaire.

For the multinomial logistic regression, we constructed the 3-category independent variable “Protection strategy” with modalities “Consistent condom use” (coded 2), “Risk reduction” (coded 1), and “No or inconsistent condom use” (coded 0). We used information from the question on condom use with the casual partners of the last 12 months (with response modalities “Always,” “Sometimes,” “Never”) and from the above 3 risk reduction questions. We gave priority to information on risk reduction strategies: first, participants who mentioned “always condom use” were classified as “Consistent condom use”; then any participant who mentioned at least 1 risk reduction practice was included in the “Risk reduction” modality (ie, even if he had also reported consistent condom use); finally, the remaining participants were classified as “No or inconsistent condom use.”


The analyses were restricted to the participants who reported having had anal intercourse with at least 1 casual partner during the past 12 months (n = 1689, 57.2% of the Gaysurvey participants). The prevalence of each protection strategy and the respective prevalence of risk reduction practices among those having adopted-at least once-this protection strategy were evaluated.

We used PASW Statistics 18 (SPSS Inc., Chicago, IL) to run multinomial logistic regression to identify predictors of being classified as either “No or inconsistent condom use” or “One or more risk reduction practices” over “Consistent condom use.” To avoid the “fitting to noise” problem, we restricted the list of regressors to age and variables related to sexual activity. The following variables were used as predictors: age (in years) and age squared as covariates; included factors were steady relationship with a male partner during the past 12 months (category of interest: yes, coded 1; reference category: no, coded 2), number of sexual partners during the past 12 months (above median of 5: 1; at or below median: 2), regular visiting of sex-on-premises venues (yes: 1; no: 2), regularly seeking sexual partners through the Internet during the past 12 months (yes: 1; no: 2), having visited a prevention Web site of the Swiss AIDS Foundation containing information on harm reduction practices during the past 12 months (yes: 1; no: 2), and current HIV status (category of reference: negative, coded 3; not tested or nonresponse: 2; positive: 1).

We fitted 3 nested models to the data, removing nonsignificant regressors according to results of the likelihood ratio test at the 0.05 significance threshold. Model 1 included all regressors plus interaction terms for each regressor with HIV status. Model 2 included all regressors plus the significant interaction term, and model 3 included significant regressors plus the significant interaction terms.


Overall, 1689 persons (57.2% of Gaysurvey participants) reported anal intercourse with a casual partner in the past 12 months. About three-quarters of these participants were ever tested for HIV and knew their result. The proportion of HIV positive among participants having had casual partners who were tested was higher than in the whole Gaysurvey sample: 12.5%, compared with 12% and 6% for the paper and Internet questionnaires, respectively.36

The overall protection strategy with casual partners, according to the status of respondents, is shown in Table 1: 67.4% of participants used condoms consistently; 24% declared having used a risk reduction practices at least once during the past 12 months, to avoid HIV transmission; and 8.5% used condoms inconsistently without having used any risk reduction practice. The ranking of these strategies was the same across the HIV status categories; however, HIV-positive participants were more likely not to have used condoms consistently and to have had risk reduction practices.

Table 1:
Protection Strategy Over the Past 12 Months According to the HIV Status of the Respondent*

Among those who did not use condom consistently, 406 (73.8%) mentioned the intentional use of any risk reduction practice(s). As regards the type of risk reduction practice adopted: Of the 406 participants who reported having used 1 or more of them in the past 12 months, 50% had practiced serosorting and 33% practiced strategic positioning, about two-thirds of participants (62%) reported practicing withdrawal before ejaculation, 53% used only 1 of the 3 practices, 38% reported 2 practices, and 9% reported 3.

Running model 1 of the multinomial logistic regression (data not shown), we found that HIV status had significant interaction with only one of the regressors: the number of sexual partners in the last 12 months (dichotomized at the median). Running model 2 with nonsignificant interactions removed, we further found that the predictor “regular frequency of sex-on-premises venues” was also not significant (data not shown) and was removed from model 3 (Table 2).

Table 2:
Results of Multinomial Logistic Regression (Model 3)

Almost all predictors were significant in this final model: number of partners above median, stable relationship, Internet partner seeking, having visited a risk reduction Internet site, age, and age squared. Regarding HIV status, only HIV status positive in interaction with number of partners above median was significant. Most predictors were similarly associated (magnitude and direction) with both regression categories. Four significant adjusted odds ratios were similar for “No or inconsistent condom use” and for “One or more risk reduction practices”; 3 of them were of a very similar magnitude: Internet partner seeking (odds ratio about 1.5), age (about 0.9), age squared (1.001); the interaction between HIV status positive and number of partners was in the same direction but with a larger magnitude in “No or inconsistent condom use” (6.1) than in “One or more risk reduction practices” (2.5).

Two predictors were significantly negatively associated with only one regression category: being in a stable relationship with the risk reduction category and visiting a risk reduction Web site with the no or inconsistent condom use category. However, in both cases, the association with the other regression category was similar in direction and magnitude but not significant.

The only association that differed markedly between the 2 regression categories was having a number of partners above median, significantly associated with the risk reduction category.


This study estimates the intentional use of HIV risk reduction practices in MSM who reported having UAI with casual sexual partners. The study found that, among MSM, the main protection strategy in case of anal intercourse with casual partners remains the consistent use of condoms and that there are significant differences in complying with this strategy according to HIV status. Although the frequency order of protection strategies-consistent condom use, use of risk reduction practices, and inconsistent or no condom use-is identical across HIV status groups, HIV-positive persons are less likely to consistently use condoms and more likely to use risk reduction practices than HIV-negative or persons with unknown HIV status. HIV-positive status, in interaction with the number of partners, also appears as a factor associated with both protection strategies including a nonsystematic use of condoms. Risk behavior37,38 (nonuse of condoms or high number of partners) and risk reduction practices are often associated with positive HIV status.27,39,40 In a recent review, van Kesteren et al11 showed that HIV-positive MSM were more likely to engage in UAI with other HIV-positive MSM than with those who were HIV negative, in both primary and nonprimary relationships. However, in line with results from France6 and Australia,23 our data show that risk reduction practices were not limited to HIV-positive MSM.

About three quarters of MSM try to reduce the risk of HIV infection while having unprotected sex by using withdrawal before ejaculation, serosorting, or strategic positioning, ranked here in their order of frequency. None of these practices achieve the same level of efficacy as condom use, especially in the context of casual relationships. Moreover, any level of protection these practices may offer can be altered by contextual factors that are beyond the individual's control. The efficacy of serosorting, for example, depends highly on the prevalence of acute HIV infections26,41 and on the accuracy and veracity of the information presumably shared by the sexual partners, particularly HIV status. Serosorting may increase HIV transmission when the prevalence of acute infections is high. The risk of HIV transmission is higher during the first phase of HIV infection, when HIV is most often undiagnosed. The most frequently used practice by the respondents, withdrawal before ejaculation, is of great concern because this practice was shown to be the least effective by Jin et al.27

Risk reduction practices used with the intention to avoid HIV transmission were highly prevalent among MSM who reported UAI with casual partners. Such practices were never promoted as such in Switzerland by either public health authorities or HIV prevention or gay organizations; on the contrary, the prevention Web site of the Swiss AIDS Foundation warns about their questionable efficacy. However, we could not ascertain the frequency of and the context in which the study participants used these strategies, that is, whether they used these strategies consistently as an alternative to condom use or whether they adopted these practices opportunistically in the heat of the moment for different contextual reasons such as no condom at hand, substance consumption, familiarity with the partner, emotional state, and so on. The results of the multinomial regression suggest that the second interpretation may be more accurate: We found few differences between the protection strategies “one or more risk reduction practices” and “no or inconsistent condom use” compared with “consistent condom use”: Most of the variables showed the same direction of association in both situations and are probably markers of overall nonsystematic condom use with casual partners, that is, HIV-positive status in interaction with high number of partners, younger age, Internet partner seeking,42 and not being in a stable relationship. The only statistically significant association in an inverse direction was the association of intentional use of risk reduction practices with a higher number of partners, which may be interpreted as the result of an opportunistic decision by people who-having more partners-have a higher risk of being once in a situation of nonuse of condoms.

Our results have implications in terms of research and prevention. Regarding research, we need to better understand the contextual factors surrounding harm reduction practices and to ascertain whether these practices consist of finalized strategies used as alternatives to condoms or opportunistic decisions. Qualitative insights are also needed. Regarding prevention, it is necessary to recognize the most commonly used risk reduction practices among MSM who do not systematically use condoms and to address these practices in prevention activities in a balanced way. It is important to stress that highlighting these practices is not equivalent to promoting them. MSM need accurate knowledge about the conditions under which these practices might actually reduce the risk of HIV transmission.

Limitations and Strengths of the Study

As part of the Swiss Behavioral Surveillance System initiated in 1987, the survey used in this study was based on a nonprobabilistic sample. This approach allows for national coverage at a reduced cost. The broad dissemination of our questionnaire (gay press, gay Web sites, and gay organizations and venues) assured that our sample population was highly diverse if not representative. One can expect, however, that this method could overestimate the level of risky behavior.

Currently, many studies use different approaches to address risk reduction practices in MSM. However, most of the studies were limited to triangulating behavioral observations without inquiring about the intentional character of the harm reduction practices.2,18,23,33 Other studies investigated risk reduction practices by analyzing risk representations.17,19 Our approach permitted us to estimate the prevalence of intentional harm reduction practices but was insufficient to ascertain whether these practices were used consistently or opportunistically or to understand MSM's beliefs concerning their level of protection.


Warm thanks to the participants, who responded to the survey, and the associations, establishments, Web sites, and magazines that distributed the questionnaire.


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risk reduction; HIV prevention; homosexuals; sexual behavior; serosorting; strategic positioning; withdrawal

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