In addition, IDUs decreased needle sharing and attended shooting galleries less frequently during study period and those IDUs, who attained higher degrees of education, were older, and were women were less likely to contract HIV. Higher annual income, being married, and not being homeless were also significant indicators of reduced HIV incidence. The researchers say these variables were associated with increased social support and resources to help avoid or reduce high-risk behavior.
"These trends reflect, in part, the response to a concerted public health effort to prevent HIV infection among drug users and the response to the risk of acquiring HIV by drug-using populations," said Kenrad Nelson, MD, a study co-author and professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.
According to the study, drug users who injected on a daily basis, used cocaine as well as heroin, or used shooting galleries were found to be more at risk of acquiring HIV. The researchers also found that older users were more likely to be HIV-positive and more often introduced drugs to younger users.
Previous studies have shown that several drug-related behaviors have been associated with an increased risk of HIV infection, such as injection of cocaine or multiple drugs, increased frequency of injection, sharing of injection paraphernalia (especially with more than one partner), and use of a shooting gallery. Researchers conducted semiannual interviews, between 1988 and 1998 with 1,532 HIV-negative injection drug users in Baltimore to study the rates of new HIV infections. They found decreasing rates of new HIV infections in these drug users over this time period. In addition, the rates of new infection decreased similarly among 338 drug users who were recruited in 1994. In this study of drug users, the rates of new HIV infection declined from 4.45 percent per year in 1988-1990 to 3.35 percent in 1991-1994 and 1.84 percent in 1995-1998.
The researchers say both sexual and drug use behavior contributed to HIV infections in the study group. The study shows that sexually transmitted infections during the period immediately prior to HIV seroconversion, male homosexual activity, and sex with another injection drug user were associated with increased HIV incidence. Young IDUs and those new to drug use were found to be at a higher risk of contracting HIV as well.
"The reduction of HIV incidence, as well as high-risk behavior among drug users in Baltimore in recent years is a very encouraging finding. It is increasingly evident that preventing HIV infection in injection drug users is feasible and that populations of injection drug users in several cities in the United States and Europe are experiencing a lower incidence of HIV than they were a decade ago," said Dr. Nelson.
"Temporal Trends in the Incidence of Human Immunodeficiency Virus and Risk Behavior among Injection Drug Users in Baltimore, Maryland, 1988-1998" was written Kenrad Nelson, Noya Galai, Mahboobeh Safaeian, Steffanie A. Strathdee, David D. Celentano, and David Vlahov and appears is published in the October 2002 issue of the American Journal of Epidemiology.
The study was funded by grants from the National Institute on Drug Abuse.