Researchers gathered data on drug use and sexual activity during semi-annual interviews. Blood samples from participants were also retrieved at each visit. The study shows high-risk sexual behavior was the biggest predictor of HIV infection among intravenous drug users. Researchers found drug use and homosexual activity are the most important predictors of HIV infection among males, and high-risk heterosexual activity is the main predictor for HIV infection among females. Male drug users who reported homosexual activity were four times more likely to become infected with HIV, and in the female population, HIV infection was more than two times higher among women who reported having sex with another drug user than in women who used drugs but did not report any sexual activity with another drug user.
Researchers say age is also an important determinant.
They found drug users aged 30 and younger were more than twice as likely to develop HIV than those aged 40 and over.