Most common individual substance-related incidents and odds ratio (OR) among first aid station visitors (%).

Alc = alcohol. Amp = amphetamines. Can = cannabis. Coc = cocaine. Ecs = ecstasy. More than one symptom can occur in combination with each substance. Reference category for the logistic regression analysis is not reporting use of each of the substances. 95% CI = 95% confidence interval (lower-upper). ORs are available only for variables included in the forward stepwise model.