To the Editor.
—The recent study by Dr Avins and colleagues1 indicated that in an urban public alcohol treatment center population, human immunodeficiency virus (HIV) infection was far more common than in the general population. The study did not examine the independent contribution of noninjection use of cocaine to the increased seroprevalance of HIV infection.Cocaine is a powerful stimulant and aphrodisiac and frequently causes disinhibition. The urban cocaine culture is characterized by crack houses where drugs are often exchanged for sexual favors. Concomitant use of cocaine and alcohol is common in such settings. Because of the large number of study patients who use both alcohol and cocaine, the independent contributions of these substances could not be measured. A more accurate conclusion of this particular study would be that the concomitant use of alcohol and noninjection drugs is associated with an increased prevalence of HIV infection and that further