A report from the Centers for Disease Control and Prevention (CDC) found that 17 percent of all new adolescent and adult HIV/AIDS cases reported in 2006 were caused by injection-drug use, the Center for Substance Abuse Research at the University of Maryland at College Park reported April 7.

The CDC said that 13 percent of the cases were solely linked to injection-drug use, while 4 percent were caused by injection-drug use in combination with male-to-male sexual contact.

Overall, male-to-male sexual contact was blamed for 50 percent of all new HIV/AIDS cases in 2006, while 33 percent of cases were linked to high-risk heterosexual contact. The study was limited to HIV/AIDS among individuals ages 13 and older in the U.S.

The findings were published in the CDC's annual HIV/AIDS Surveillance Report.