Assertion: thc's significance | /r/CapableOf | disappear in large case-control study
Facets:
value: after controlling for drivers’ age
type: TEMPORAL
Source sentences:
text: However, in a large case-control study, the significance of cannabis use disappeared after controlling for drivers’ age, gender, race, and the presence of alcohol.38 A complicating factor in determining crash risk is the difficulty of assessing cannabis impairment in the field, particularly compared to assessing impairment due to alcohol.