US study suggests circumcision does not protect black or Latino MSM from HIV

A new study from the United States has found no statistically significant evidence that being circumcised protects against HIV infection amongst black or Latino men who have sex with men (MSM) – even amongst those MSM who said they also had sex with women and/or practised insertive intercourse only.

The study, from the US Centers for Disease Control and Prevention (CDC), which was published in the December 15^th issue of the Journal of Acquired Immune Deficiency Syndromes, was also presented at last week’s National HIV Prevention Conference in Atlanta.

Since the publication of the positive results of circumcision studies amongst heterosexual men in Africa, experts have been considering whether male circumcision could work as an HIV prevention strategy in other populations and settings.

It’s currently unknown whether the results of the African studies could apply to MSM in the United States, and whether MSM who only practise the insertive role may benefit from circumcision.

Since black and Latino MSM are disproportionately affected by HIV in the United States, compared to white MSM, the CDC wanted to examine the characteristics of circumcised and uncircumcised black and Latino MSM in order to assess the association between circumcision and HIV infection.

Their ‘Brothers y Hermanos study’ recruited 2235 black and Latino MSM in New York, Philadelphia, and Los Angeles between May 2005 and April 2006.

Participants were asked, “Is your penis circumcised or cut?” Of the 2245 men who completed the survey, 2106 answered this question. An additional 70 men who indicated that they spoke and read primarily in Spanish but took the English survey were excluded from the analysis. The final sample for the analyses therefore included 1079 black MSM and 957 Latino MSM.

They found that black MSM were more likely to be circumcised compared with Latino MSM (74% vs. 33%; p < 0.0001).

Circumcised black MSM were more likely to be older, have a higher level of education, a higher income, be born in the US, and identify as gay than uncircumcised black MSM. Circumcised black MSM also reported greater rates of recent unprotected anal intercourse (UAI) and being the receptive partner during anal sex with a greater number of male partners than uncircumcised black MSM. In addition, circumcised black MSM were more likely than uncircumcised black MSM to report using marijuana or amyl nitrites in the past three months.

There were fewer differences between circumcised and uncircumcised Latino MSM, but circumcised Latino MSM were significantly more likely than uncircumcised Latino MSM to be born in the US, and to report using cocaine, heroin, or crystal methamphetamine in the past three months. In addition, circumcised Latino MSM were more likely than uncircumcised Latino MSM to report a greater number of previous HIV tests and to be tested in the past year.

There were no differences in health insurance coverage by circumcision status for either black or Latino MSM, and circumcision status was not associated with ever being diagnosed with a sexually transmitted infection (STI) or HIV infection.

The investigators then analysed the data controlling for these demographic characteristics and sexual risks and found that there was no statistically significant association between circumcision and HIV status among Latino MSM (adjusted odds ratio [AOR] = 1.10, 95% confidence interval [CI]: 0.73 to 1.67) or black MSM (AOR = 1.23, 95% CI: 0.87 to 1.74).

The investigators then compared men who reported recent male sex partners only with men who reported recent male and female sex partners. These analyses were restricted to black men because only a small number of Latino men reported sex with female partners in the past three months. Again, they found that circumcision was not significantly associated with HIV infection (AOR = 0.99, 95% CI: 0.41 to 2.37) among black men who had recent sex with men and women or among black men who had recent sex with men only (AOR = 1.45, 95% CI: 0.85 to 2.44).

Although they found that being the insertive partner during recent unprotected anal sex was associated with reduced odds of being HIV-positive among black men who only reported recent sex with other men, the association was not statistically significant for black men who had recently had sex with both men and women.

The investigators say that, “if the results from the African circumcision trials were directly applicable to the MSM in our study, we would have expected to observe a significantly higher prevalence of HIV infection among uncircumcised men.”

They note that instead, they found that “circumcision conferred neither risk nor protection among black men or Latino men in our study, however, and was unrelated to seroconversion among MSM who reported that their last HIV test was negative. Further, there was no evidence that circumcision was protective among men who had only engaged in unprotected insertive anal sex in any of the models.”

Although two previous US studies examining the relationship between circumcision and HIV status suggested that circumcision conferred a protective effect from HIV infection these previous studies had primarily enrolled white MSM. The investigators think this study came to different conclusions “because HIV infection is disproportionately higher among black and Latino MSM than among white MSM in the United States” and it is possible that “the greater background prevalence of HIV infection in black and Latino MSM communities diminishes any protective effect afforded by circumcision.”

Their results do agree, however, with more recent studies among MSM in Peru and Australia: the latter, they note, was a prospective study which “found no association between circumcision status and HIV incidence among all MSM who seroconverted or among the subset of newly infected men who had engaged exclusively in insertive anal sex.”

The investigators point out several limitations to their study, notably that their “data are cross-sectional and do not permit causal inferences.”

They do not rule out circumcision as a prevention method, however, and argue that this study is not conclusive, and that “additional observational studies need to be conducted before any definitive conclusions can be drawn about the association between circumcision status and HIV infection among black MSM and Latino MSM in the United States.”