Introduction:

Cannabis is the most widely used illicit drug worldwide and the second most smoked substance after tobacco. In recent years, numerous studies have attempted to assess its impact on respiratory health with conflicting results.

Objective:

To study the effect of inhaled cannabis on respiratory symptoms and lung function compared to tobacco and non-smokers.

Methods:

Adults from cannabis clubs and public institutions in our country were included. Questionnaires on sociodemographic characteristics, respiratory symptoms, and consumption habits were conducted. This was complemented with pulmonary function testing. Participants were divided into 4 groups: cannabis group (C), tobacco group (T), cannabis-tobacco group (C-T), and non-smokers group (NS).

Results:

A total of 375 individuals were studied: cannabis group (63), tobacco (117), cannabis-tobacco (50), and non-smokers (145). The cannabis, cannabis-tobacco, and tobacco groups showed a higher prevalence of at least one chronic respiratory symptom (wheezing, cough, and sputum) compared to the non-smokers group (p<0.001). Forced vital capacity was significantly higher in cannabis users (C, C-T). No other significant spirometry alterations were found.

Conclusions:

Smoking cannabis is associated with chronic respiratory symptoms. Although no clinically relevant changes in lung function were detected, further long-term studies are required. Inquiry about cannabis use should be incorporated into clinical practice, with education on potential health risks.

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