TRACHEOBRONCHIAL HISTOPATHOLOGY IN HABITUAL SMOKERS OF COCAINE, MARIJUANA, AND OR TOBACCO/

Background: Marijuana and alkaloidal cocaine (''crack'') are the two m ost commonly smoked substances in the United States after tobacco. Whi le regular tobacco smoking has been found to be associated with extens ive microscopic alterations in bronchial mucosa, little information is available concerning the effect of crack cocaine and marijuana on tra cheobronchial histopathology. Study objective: To determine the relati ve impact of smoked substances (cocaine, marijuana, and tobacco) alone and in combination on the histopathology of the tracheobronchial muco sa and to assess whether the effects of habitual smoking of two or mor e substances (cocaine, marijuana, and/or tobacco) are additive. Design : Observational cohort study. Subjects: Fifty-three nonsmoking control subjects (NS), 14 current, habitual smokers of crack cocaine only (CS ), 40 current, regular smokers of marijuana only (MS), 31 regular smok ers of tobacco only (TS), 16 current smokers of both cocaine and marij uana (CMS), 12 current smokers of both cocaine and tobacco (CTS), 44 c urrent smokers of both marijuana and tobacco (MTS), and 31 current smo kers of cocaine, marijuana, and tobacco (CMTS). Methods: After prelimi nary screening evaluation, including a detailed respiratory and genera l health questionnaire and routine pulmonary function studies, subject s underwent fiberoptic bronchoscopy with endobronchial biopsies of the mucosa of the primary carina and randomly selected secondary or terti ary carinae. Biopsy specimens were processed for light microscopy, sta ined with hematoxylineosin or periodic acid-Schiff, and examined to as sess epithelial, basement membrane, and submucosal alterations by one or two pathologists who were masked to the smoking status of the subje ct. Results: Smokers of cocaine, marijuana, or tobacco alone all exhib ited more frequent abnormalities than NS in 10 (CS) or all 11 (MS and TS) of the histopathologic features assessed. For most features, MS an d TS showed significantly more frequent alterations than NS (p less th an or equal to 0.02), while CS showed significantly more frequent abno rmalities than NS in only three features (p < 0.05) and nearly signifi cant differences from NS in two additional, features (p less than or e qual to 0.09). Alterations were noted most frequently in CTS (six feat ures) and MTS (three features), while abnormalities were relatively in frequent in CMS. For 10 features, MTS had more frequent alterations th an MS and TS. With a single exception, CMTS did not show more frequent alterations than CTS or MTS. Conclusion: Marijuana and tobacco smokin g each produces significant bronchial mucosal histopathology and the e ffects of marijuana and tobacco appear additive. Cocaine appears to le ad to fewer significant bronchial mucosal alterations than marijuana o r tobacco when smoked alone and does not add to the changes associated with marijuana, When smoked together with tobacco, however, cocaine a ppears to augment the bronchial injury caused by tobacco smoking.