Health outcomes associated with long-term regular cannabis and tobacco smoking

This study aimed to identify patterns of health concerns associated with long-term use of cannabis and tobacco individually, as well as in combination. We recruited 350 adults aged 40 or over who smoked cannabis but not tobacco (cannabis-only group, n = 59), smoked both cannabis and tobacco (cannabis/tobacco group, n = 88), smoked tobacco but not cannabis (tobacco-only group, n = 80), or used neither substance (control group, n = 123). Participants completed a survey addressing substance use, diagnosed medical conditions, health concerns relating to smoking cannabis/tobacco, and general health (measured using the Physical Health Questionnaire and the Short Form 36). Several significant differences were found among the four groups. With regard to diagnosed medical conditions, the three smoking groups reported significantly higher rates of emphysema than did the control group (ps < .001). However, all members of the cannabis-only group diagnosed with emphysema were former regular tobacco smokers. Total general health scores, general health subscales, and items addressing smoking-related health concerns also revealed several significant group differences, and these tended to show worse outcomes for the two tobacco smoking groups. Findings suggest that using tobacco on its own and mixing it with cannabis may lead to worse physical health outcomes than using cannabis alone.

► Cannabis, tobacco, and combined cannabis-tobacco use are linked with emphysema.
► Adding tobacco to cannabis is linked to more smoking-related health symptoms.
► Cannabis-only users report better health than tobacco and cannabis-tobacco users.
► Mixing cannabis with tobacco may synergistically compromise health.