Changes in the prevalence of injection drug use among adolescents and young adults in large U.S. metropolitan areas.

Young injection drug users (IDUs) are at risk for acquiring blood-borne diseases like HIV and Hepatitis C. Little is known about the population prevalence of young IDUs. We (1) estimate annual population prevalence rates of young IDUs (aged 15-29) per 10,000 in 95 large U.S. metropolitan statistical areas (MSAs) from 1992 to 2002; (2) assess the validity of these estimates; and (3) explore whether injection drug use among youth in these MSAs began to rise after HAART was discovered. A linear mixed model (LMM) estimated the annual population prevalence of young IDUs in each MSA and described trends therein. The population prevalence of IDUs among youths across 95 MSAs increased from 1996 (mean = 95.64) to 2002 (mean = 115.59). Additional analyses of the proportion of young IDUs using health services suggest this increase may have continued after 2002. Harm reduction and prevention research and programs for young IDUs are needed.