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Published on: August 18, 2020
Cannabis use among motorcyclists in Brazil: prevalence and associated factors from a cross-sectional study in two
Henrique Silva Bombana1, Júlia Maria D'Andrea Greve2, Daniele Mayumi Sinagawa3
1Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brazil.
Objective:
To estimate the prevalence of cannabis use among motorcyclists and identify factors associated with tetrahydrocannabinol (THC) positivity in two major Brazilian cities.
Methods:
A cross-sectional roadside study was conducted with motorcyclists in São Paulo (2023) and Campinas (2026), Brazil. Participants completed a structured questionnaire and provided oral fluid samples, which were analyzed using liquid chromatography-tandem mass spectrometry. Multivariable logistic regression was used to assess factors associated with THC positivity.
Results:
Among 502 motorcyclists, 13.1% tested positive for at least one psychoactive substance, with THC detected in 9.6%. In adjusted analyses, age showed a non-linear association with THC positivity, with the probability of testing positive peaking at approximately 32 years and declining thereafter (age: aOR = 1.636, 95% CI: 1.080-2.480; age2: aOR = 0.992, 95% CI: 0.986-0.998). A history of prior motorcycle crash was independently associated with higher odds of THC positivity (aOR = 2.623; 95% CI: 1.053-6.534), though this estimate should be interpreted with caution given the wide confidence interval. The association between app-based delivery work and THC positivity was not statistically significant after adjustment.
Conclusions:
Cannabis use was frequently identified among motorcyclists, a high-risk group for road traffic injuries. These findings underscore the importance of strengthening monitoring strategies and generating evidence to support policies addressing drug-impaired driving in Brazil.
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