Substance use and social problems predict HIV infection in American gay men

Prospective study supports the idea of a ‘syndemic’ of intertwined problems

American gay men reporting depression, childhood sexual abuse, stimulant use, other substance use and heavy alcohol use are nine times more likely than men without any of these issues to subsequently acquire HIV, according to the findings of a large study conducted over four years reported in the Journal of Acquired Immune Deficiency Syndromes.

The more of these problems a man had, the more likely he was to later report risky sex or to become HIV positive. The study suggests that these problems are inter-connected and work together to heighten men’s vulnerability.

Numerous studies have shown that gay men and other men who have sex with men are more likely to report substance use, mental health problems, sexual abuse and other issues than other men.

Rather than seeing them as separate problems, some researchers have paid attention to how these issues, sexual risk taking and HIV infection link together. The term ‘syndemic’ is used to describe the co-occurrence of several diseases and social problems which combine together to have an especially negative impact on health. Some research on ‘syndemics’ draws attention to poverty and social marginalisation as underlying causes, with work on men who have sex with men sometimes suggesting that early experiences of homophobia, social rejection and concealment can have a lifelong impact.

Studies have already shown that gay men often report more than one psychosocial health problem and that having several health problems is significantly associated with both high-risk sexual behaviour and having HIV. But these studies have been cross-sectional – with data only collected at one point in time. They have been unable to show that interlinked psychosocial health problems occurred before sexual risk behaviour and HIV infection.

Matthew Mimiaga and colleagues therefore re-analysed data from Project EXPLORE, a cohort of 4295 men who have sex with men, recruited in six American cities in 1999-2001, and followed for four years. While the data are old, other large prospective cohorts have not been recruited in recent years.

All participants were HIV negative at the beginning of the study but 259 men (6%) acquired HIV while in the cohort. The analysis focuses on the risk factors which preceded a man’s seroconversion.

There was a variety of men of sex with men in the cohort, but the majority of participants were white, well-educated and in full time employment.

The researchers were especially interested in five syndemic health and social problems. While data were collected every six months, the baseline figures are given below:

  • 47% reported symptoms of depression.
  • 39% reported sexual abuse during childhood.
  • 25% reported stimulant drug use (any use of crack, cocaine or crystal meth in the past six months).
  • 14% reported polydrug use (using three or more non-stimulant drugs in the past six months).
  • 11% reported heavy alcohol use (four or more drinks every day, or six or more drinks on a typical day when drinking).

Just one quarter of the cohort reported none of these problems at baseline. Over one third (35%) had one, 24% had two, 10% had three, 4.3% had four, and 0.7% had five problems.

After statistical adjustment, men reporting one problem were 1.7 times more likely to go on to acquire HIV, men reporting two problems were 2.4 times more likely to do so and men with three problems were 5.3 times more likely to.

Men reporting four or five problems were 8.7 times more likely to acquire HIV.

All these associations were statistically significant.

Similarly, men reporting more problems were more likely to go on to report anal sex without a condom with a partner of unknown or different HIV status. For example, men with three problems were 2.2 times more likely to do so. Men with four or five problems were 4.3 times more likely to report this behaviour.

The researchers also found that certain combinations of problems were more strongly associated with HIV seroconversion than others combinations. Their most notable finding was that of 18 combinations associated with a higher risk of seroconversion, 15 included stimulant drug use. In contrast, of 14 lower risk combinations, only one included stimulant drug use.

But they did not find that stimulant drug use alone explained the increases in risky sex or in HIV acquisition.

The researchers suggest that a better understanding of how interconnected problems are linked to HIV risk could lead to the development of improved and more holistic prevention interventions. For example, men with both depressive symptoms and stimulant drug use (a combination associated with elevated risk of HIV infection) may benefit from counselling which addresses mental health, drug use and sexual risks simultaneously. Interventions for men who have experienced childhood sexual abuse should address the symptoms of post-traumatic stress in adulthood rather than just identifying the fact that abuse occurred.

“This study demonstrates prospectively that the accumulation of ‘syndemic’ or overlapping psychosocial problems predicts HIV seroconversion among U.S. MSM,” the authors conclude. They note that they observed a dose-response relationship between increasing numbers of syndemic conditions and elevated risk of acquiring HIV. Moreover as the study was longitudinal and prospective, it “provides compelling evidence for the directionality of the effect of syndemics on increased HIV risk among MSM.”

References

Mimiaga MJ et al. The effect of psychosocial syndemic production on 4-year HIV incidence and risk behavior in a large cohort of sexually active men who have sex with men. Journal of Acquired Immune Deficiency Syndromes, online ahead of print, 2014.