Excess mortality among people who report lifetime use of illegal drugs in the United States: A 20-year follow-up of a nationally representative survey.

Objective: The purpose of this study was to determine the mortality risks, over 20 years of follow-up in a nationally representative sample, associated with illegal drug use and to describe risk factors for mortality.

Methods: We analyzed data from the 1991 National Health Interview Survey, which is a nationally representative household survey in the United States, linked to the National Death Index through 2011. This study included 20,498 adults, aged 18-44 years in 1991, with 1047 subsequent deaths. A composite variable of self-reported lifetime illegal drug use was created (hierarchical categories of heroin, cocaine, hallucinogens/inhalants, and marijuana use).

Results: Mortality risk was significantly elevated among individuals who reported lifetime use of heroin (HR=2.40, 95% CI: 1.65-3.48) and cocaine (HR=1.27, 95% CI: 1.04-1.55), but not for those who used hallucinogens/inhalants or marijuana, when adjusting for demographic characteristics. Baseline health risk factors (smoking, alcohol use, physical activity, and BMI) explained the greatest amount of this mortality risk. After adjusting for all baseline covariates, the association between heroin or cocaine use and mortality approached significance. In models adjusted for demographics, people who reported lifetime use of heroin or cocaine had an elevated mortality risk due to external causes (poisoning, suicide, homicide, and unintentional injury). People who had used heroin, cocaine, or hallucinogens/inhalants had an elevated mortality risk due to infectious diseases.

Conclusions: Heroin and cocaine are associated with considerable excess mortality, particularly due to external causes and infectious diseases. This association can be explained mainly by health risk behaviors.