For lung cancer, a case-control study found no link to marijuana smoking (even for those smoking more than one marijuana cigarette per day for 30 years) after adjustment for confounders such as cigarette smoking.[132] Another case-control study, set in Tunisia, Morocco, and Algeria, found a higher risk of lung cancer in marijuana smokers; however, the results are difficult to interpret because all of those who smoked marijuana in the study also smoked tobacco.[133] A recent cohort study of military conscripts indicated a higher risk of lung cancer in individuals who indicated that they had smoked marijuana more than 50 times at the time of their baseline examination. The elevated risk persisted after adjustment for baseline smoking status (among factors). However, this study only collected information at a single time point.[134]