title: Injection drug users in the United States, 1979-2002: an aging population.
abstract: BACKGROUND
  Injection drug use (IDU) is important in the epidemiology of blood-borne pathogens. Herein, trends in IDU from 1979 to 2002 are analyzed.
  
  
  METHODS
  The National Household Survey on Drug Abuse is an ongoing survey of drug use among the US population 12 years and older. Participants were chosen using a multistage sampling design and interviewed by written questionnaire (1979-1998) or audio computer-assisted self-interviewing (1999-2002). Herein, we examine the prevalence of a history of IDU at any time in the past (IDU-ever) or within the past year.
  
  
  RESULTS
  In the 2000-2002 surveys, 1.5% (95% confidence interval [CI], 1.4%-1.6%) reported IDU-ever (weighted estimate, 3.4 million persons). Prevalence was highest in persons aged 35 to 49 years (3.1%; 95% CI, 2.8%-3.4%), was higher in men (2.0%; 95% CI, 1.8%-2.2%) than women (1.0%; 95% CI, 0.9%-1.1%), and was higher in whites (1.7%; 95% CI, 1.5%-1.8%) than blacks (0.8%; 95% CI, 0.7%-1.1%) or Hispanics (1.1%; 95% CI, 0.8%-1.4%). Prevalence decreased with increasing annual income and educational level. Of all participants, 0.19% (95% CI, 0.16%-0.23%) reported IDU within the past year (weighted estimate, 440 000 persons). Ten years earlier (1990-1992), 1.6% (95% CI, 1.5%-1.8%) reported IDU-ever; prevalence did not differ by race. From 1979 through 2002, the mean age of participants with IDU within the past year increased from 21 to 36 years; the age of participants with IDU-ever increased from 26 to 42 years. From 2000 to 2002, 59.4% of all persons with IDU-ever were aged 35 to 49 years.
  
  
  CONCLUSIONS
  The mean age of injection drug users has increased substantially. Persons born between the late 1940s and early 1960s have the highest prevalence of IDU-ever. Self-reported IDU rates are now lower among young blacks than young whites.
authors.affiliation: Division of Viral Hepatitis, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. GArmstrong@cdc.gov
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Armstrong
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D017677:Age Distribution; D000368:Aged; D000697:Central Nervous System Stimulants; D002648:Child; D003042:Cocaine; D005260:Female; D006306:Health Surveys; D003932:Heroin; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D017678:Sex Distribution; D012959:Socioeconomic Factors; D015819:Substance Abuse, Intravenous / Q000453:epidemiology* / Q000208:ethnology; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data
chemical_list: D000697:Central Nervous System Stimulants; D003932:Heroin; D003042:Cocaine