What was the longest length of time you stopped smoking because you were trying to quit:Time:Pt:^Patient:Qn:PLCO
what was the longest length of time you stopped smoking because you were trying to quit:time:pt:^patient:qn:plco
What was the longest length of time you stopped smoking because you were trying to quit [PLCO]
what was the longest length of time you stopped smoking because you were trying to quit [plco]