Table 2.

Main findings from studies on cannabis and risk factors or doping laboratory analysis (n = 7)

Study, Year	Type of Study	Participants, n	Age Range, y	Female, %	Cohort	Main Findings
Ewing, 199820	Cross-sectional	1458	NR	46.7	National Longitudinal Youth Survey (1992)	Male athletes were more likely to have used marijuana than non-athletes.
Peretti-Watel et al, 200244	Cross-sectional	10,807	14-19	52.1	French national school survey of all adolescents (1999)	U-shaped curve was found between male sport participation and cannabis use.
Van Eenoo and Delbeke, 200361	Cross-sectional	14,995	NR	13.4	Urine samples from the IOC and Flanders analyzed in a doping control laboratory, Ghent, Belgium (1996-2000)	Reports showed a significant increase in samples containing cannabis over time, and it was detected in all types of sports studied.
Strano Rossi and Botrè, 201155	Cross-sectional	95,000	18-35	25	Athlete urine samples taken from the Italian Anti-Doping Laboratory over a 10-year period (2000-2009)	Marijuana (THC metabolite) was the most frequently found drug (0.2%-0.4% of samples).
Buckman et al, 20138	Cross-sectional	11,559	18-23	0	Male undergraduate NCAA college student-athletes (2008-2009)	Reports showed a higher prevalence of marijuana among performance-enhancing substance users compared with nonusers.
Veliz et al, 201662	Cross-sectional	21,049	13-18	50.9	American College Health Association—National College Health Assessment Study (2008-2012)	Participation in competitive sport was not associated with 30-day marijuana use. However, odds of past 30-day use was higher in high-contact sports.
Boyes et al, 20176	Cross-sectional	13,817	14-15	49.3	National Canadian adolescents from the Health Behaviour in School Age Children data (2013-2014)	Team sport participation was associated with lower prevalence levels of cannabis use and a protective effect of cannabis use for females.

IOC, International Olympic Committee; NCAA, National Collegiate Athletic Association; NR, not reported; THC, tetrahydrocannabinol.