Peak expiratory flow in youths with varying cigarette smoking habits.

Measurements of peak expiratory flow (P.E.F.) were done on 195 boys arriving at a detention centre, and again eight weeks later at the time of their discharge. During this time they took much physical exercise, and cigarette smoking and drug taking were not permitted. At the initial assessment there was an impairment of P.E.F. inversely proportional to the amount of cigarettes smoked which was statistically significant. There was a significant improvement in P.E.F. between reception and discharge in all groups of boys with varying smoking habits, all groups except the heavy smokers achieving near normal results after eight weeks. The heavier smokers improved more than the non-smokers or light smokers, but this difference was not statistically significant. Suggested reasons for this improvement are discussed.