anal sex roles is a likely explanation for the continued high rate of new HIV
transmissions among men who have sex with men (MSM) in the United States,
results of a study published in the online edition of the Journal of Acquired Immune Deficiency Syndromes suggest.
Investigators found that almost two-thirds of HIV-negative MSM engaging in
unprotected anal sex were sexually versatile, adopting both the insertive and
“Versatile men at high infection risk via receptive UAS
[unprotected anal sex] are likely to transmit HIV via insertive UAS,” comment
the authors. The results also showed
that only 17% of men were exclusively insertive, suggesting that circumcision
would have little impact on the course of the HIV epidemic among US MSM.
Over half of new
HIV infections in the United States are among gay and other MSM. Almost all the
HIV infections in this population are due to unprotected anal intercourse, and
the risk of infection with HIV is especially high for men who adopt the
receptive role during unprotected anal sex.
Little is known
about anal sex position among high-risk MSM in the United States.
the EXPLORE study therefore examined data obtained from over 2500 HIV-negative
men reporting unprotected anal sex. Participants were recruited between 1999
and 2001 and followed for an average of 3.25. Every six months, individuals were
asked which role they had adopted during unprotected anal sex: exclusively
insertive; exclusively receptive; or both (versatile). The investigators
conducted a series of analyses to see if there were any factors associated with
role and position during unprotected anal intercourse.
The men had a mean
age of 34 years, three-quarters were white and two-thirds had a college degree.
Non-injection drug use – including poppers – was highly prevalent and reported by 65% of participants.
Overall, 63% of
men reported that they were versatile and had both insertive and receptive
unprotected anal sex. These versatile men reported a median of eight
unprotected anal sex episodes in each six-month period.
Only 17% of men
said they were exclusively insertive. Exclusively insertive men reported a
median of one unprotected anal sex act per six-month period. The remaining 10%
of men said they were exclusively receptive, and they also reported a median of
one episode of unprotected sex per six months.
on the 70% of study visits where unprotected anal sex was reported.
with an HIV-negative partner was reported at 9000 of these visits; with a man
of unknown status at 5924 of visits; and with an HIV-positive partner was
reported at 1980 visits.
For visits with
unprotected anal sex, 20% were classified as exclusively receptive, 31% as
exclusively insertive and 49% as versatile.
The HIV status of
partners appeared to influence sexual positioning. With HIV-positive partners,
54% of reported episodes of unprotected sex were exclusively insertive. A
similar proportion of instances of unprotected anal sex with HIV-negative
partners were versatile. With partners of unknown status, the most prevalent
role was exclusively insertive (46%).
50% more likely to report being exclusively insertive when they did not know
the HIV status of their partner (aRRR = 1.51; 95% CI, 1.29-1.77, p <
0.0001). The odds of being exclusively insertive increased by a factor of two
and a half when the partner was known to be HIV positive (aRRR = 2.34; 95% CI,
1.98-2.75, p < 0.0001).
receptive compared to being exclusively insertive was more likely among men
reporting the use of poppers (aRRR = 1.21; 95% CI, 1.05-1.41, p =0.01). Men
aged 25 and younger were the age group most likely to report being exclusively
receptive. The odds of this decreased with age and were lowest for those aged 36 and
older (p < 0.0001).
“Our finding that
exclusively receptive men during UAS tended to be younger might be contributing
to the rising HIV incidence in young MSM in the US,” suggest the investigators.
associated with the HIV status of partners. Participants were 34% more likely
to report being exclusively insertive with a man whose HIV status they did not
known and 3.5 times more likely with HIV-negative compared to HIV-positive
significantly less likely to be versatile compared to exclusively insertive is
they were older or black. Versatility was positively associated with sex with a
regular partner and use of several substances, including poppers, amphetamines
of men reported both insertive and receptive positions…with only a small
proportion remaining exclusively insertive or receptive,” comment the authors,
who note “several modeling studies proposed that greater role versatility could
promote HIV transmission”. They believe their results underline the importance
of “examining anal sex role patterns in understanding factors driving the HIV
epidemic among MSM”.