A case–control study of lung cancer in adults f55 yrs of age was conducted in eight district
health boards in New Zealand. Cases were identified from the New Zealand Cancer Registry and
hospital databases. Controls were randomly selected from the electoral roll, with frequency
matching to cases in 5-yr age groups and district health boards. Interviewer-administered
questionnaires were used to assess possible risk factors, including cannabis use. The relative
risk of lung cancer associated with cannabis smoking was estimated by logistic regression.