A
longitudinal study using multiple cohorts of young men who have sex with men in
Chicago aimed to investigate changes in condom use over time, from late
adolescence to adulthood (aged 17-26), as well as historical patterns of change
for cohorts of men recruited in different years. This research was carried out
by Gregory Swann and colleagues at Northwestern University and is published in
the May issue of The Archives of Sexual
Behavior.
Researchers
found that while men had more anal sex as they got older, there was a decrease
in the proportion of that sex that was condomless. In terms of historical
changes, of the three cohorts followed (recruited in 2007, 2010 and 2015), the
2015 cohort reported less condomless sex at age 17, but a higher growth in the proportion
of sex that was condomless as they got older. This study is the first of its
kind to indicate that cohorts recruited in more recent years may have different
risk trajectories over time when compared to cohorts recruited previously.
Young men
who have sex with men (MSM) have the highest HIV incidence in the US. Between
2001 and 2011, youth between the ages of 13 and 24 represented the fastest growing
age group for new infections. In 2015, rates of new diagnoses stabilised for
this age group but continued to increase among MSM aged 25-34, with a 23%
increase from 2010 to 2015.
“Given these
high rates and trends, understanding how HIV risk changes from adolescence to
young adulthood is especially important,” the authors say. “The goal of the
present study was to observe how engagement in condomless anal sex changes over
time from late adolescence to adulthood in young MSM. We also set out to assess
whether cohorts of young MSM
recruited in 2007, 2010, and 2015 differed in patterns of change in condomless
anal sex from late adolescence to adulthood.”
In terms of
historical changes, social factors, such as greater recognition of same-sex
relationships and marriage equality, and biomedical developments, such as
pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP), may have had
an impact. However, PrEP is only FDA-approved for those over 18 years of age
and uptake has been low among young MSM, especially those of colour. Thus,
condom use is still an important HIV prevention tool for this at-risk group.
Turning to
changes as young men get older, previous longitudinal research on condom use
has had varied findings. One study found that MSM who were younger at baseline
were more likely to have higher increases of condomless sex over time; another found
no significant changes over time in terms of condomless sex acts; and one reported
that individuals were inconsistent over time in their
sexual risk behaviour. However, these studies tended to follow
men for less than two years and thus do not offer insight into change over
longer periods of time.
The current study
Data came
from RADAR: a longitudinal cohort study of HIV risk among young MSM in Chicago.
Three cohorts of MSM between the ages of 16 and 20 were recruited in 2007 (N =
117), 2010 (N = 450) and 2015 (N = 589). The study is ongoing, with data
collection occurring in waves (six to 18-month intervals) and the oldest
participant is now aged 26. At each wave, participants provide demographic data
and information on sexual acts with their three most recent sexual partners in
the previous six months.
Average age
at baseline was 19 years, while the average age at the most recent wave was 21.
African Americans made up 38% of the entire sample, with 26% Latino, 25% White
and 11% Asian/Pacific Islander, Native American or other. The majority (69%)
identified as gay, 23% as bisexual and 8% as other.
Results
A consistent pattern
of developmental change was seen as young MSM made the transition from late
adolescence to adulthood. Young MSM increased the average number of anal sex
acts by approximately one additional act for each year of age, although this
was not statistically significant. At the same time, the proportion of sex acts
that were condomless decreased
significantly, especially with casual partners.
On average, at age 17,
young MSM had 10.2 anal sex acts and 57% of these were condomless (an average
of 5.8 condomless sex acts). At 26, there was an average of 19.5 anal sex acts
and 30% of these were condomless (an average of 5.9 condomless sex acts).
While the proportion of
condomless acts decreased by nearly half, the absolute
numbers of condomless acts were comparable. While younger men were engaging in less
anal sex, acts were more likely to be condomless. However, as they aged, they
were more likely to use condoms but were also having more sex and thus sexual
risk did not necessarily decrease across development.
In terms of historical changes, the 2015 cohort reported a significantly lower proportion of condomless sex acts at age 17 but a significantly higher growth in condomless sex over time when compared to the 2010 cohort. The 2010 cohort averaged 5.8 condomless acts at age 17, 6.4 condomless acts at age 23 and 5.86 condomless acts at age 26. In comparison, the 2015 cohort averaged 3.24 condomless acts at age 17, increasing to an average of 8.71 condomless acts at age 23.
If this trajectory
were to continue, they would average approximately 12 condomless acts at age
26. Thus, over time, the most recent cohort will be less likely to use condoms
in comparison with earlier cohorts.
Conclusion
Consistent
developmental change was seen over time, with an increase in the number of
sexual acts and a decrease in condomless sex as the men aged. Historically, the
findings for the 2015 cohort revealed that while they were more likely to use
condoms at age 17, they were less likely to do so as they got older.
Results for cohorts
recruited in earlier years suggest that they displayed less risky behaviour
over time, especially when it came to casual partners. This may indicate the
effects of focused prevention campaigns aimed at young MSM. The authors argue that
the increase in risky behaviour in the more recent cohort might indicate a need
for renewed prevention campaigns.
While these findings
shed light on important differences between condom use in different cohorts,
the researchers do not report on those who did start PrEP after the age of 18
in the different cohorts. Another important preventative aspect, even in the
absence of condoms, is if an HIV-positive sexual partner is undetectable as
there is no chance of infection in these instances. The researchers also did
not report on how many men in these cohorts became infected with HIV.
Nonetheless, the
authors make an important point and conclude by saying: “The continuation of
the current pattern predicted in these models, if it occurs, could hint at even
higher rates of infection for 25–34-year-old MSM than what currently occurs.
Increased adoption of PrEP taken as directed could mitigate this potential
future HIV risk, but not risk of other STIs.”
