Tobacco use and nicotine dependence among HIV-infected and uninfected injection drug users

Introduction: Urban U.S. populations are burdened by intersecting epidemics of HIV infection, injection drug use, and cigarette smoking. Given the substantial morbidity attributable to tobacco in these populations, we characterized smoking behaviors, nicotine addiction, and tobacco exposure among HIV-infected and HIV-uninfected injection drug users (IDUs) in Baltimore, Maryland.

Methods: Smoking behaviors among participants in the ALIVE Study were assessed using interviewer-administered questionnaires. Smoking history and nicotine dependence (Fagerstrom Index scores) were compared by HIV and drug injecting status. Serum cotinine (a nicotine metabolite) was measured for a sample of participants by enzyme immunoassay.

Results: Among 1052 participants (29.7% HIV-infected, 39.8% active injectors), 85.2% were current smokers and 9.3% were former smokers. Smoking prevalence, age at smoking initiation, and cumulative tobacco exposure were similar by HIV status. Median Fagerstrom scores of 4 for HIV-infected and HIV-uninfected smokers indicated moderate nicotine dependence. Daily cigarette consumption was identical by HIV status (median 10 cigarettes), although HIV-infected participants were less likely to smoke 1+ pack daily compared to HIV-uninfected participants (18.0% vs. 26.9%, p=0.001). Compared to former injectors, active injectors had higher smoking prevalence (90.5% vs. 81.7%, p=0.0001), greater daily cigarette consumption (30.7% vs. 19.6% smoked 1+ pack daily, p=0.0001), and slightly higher Fagerstrom scores (median 5 vs. 4). Cotinine levels paralleled self-reported cigarette consumption.

Discussion: Tobacco use is extremely common among inner-city IDUs. Smoking behavior and nicotine dependence did not materially differ by HIV status but were associated with active drug injection. Cessation efforts should target the dual dependence of cigarettes and drugs experienced among this population.