Serum angiotensin converting enzyme activity in ex-smokers

Abstract A low activity of angiotensin converting enzyme (ACE) has been reported in people who smoke. To determine whether this low ACE activity would be reversible on cessation of smoking, we measured serum ACE activity in 107 healthy male volunteers. They included 27 active cigarette smokers, 28 non-smokers, 24 ex-smokers who had stopped smoking for less than 10 yr, and 28 ex-smokers who had stopped smoking for more than 10 yr. The mean value (±SD) of serum ACE in those who had stopped smoking for more than 10 yr was comparable to that of non-smokers: 23.2 ± 5.1 and 23.5 ± 4.5, respectively. ACE activity in smokers and the ex-smokers who had stopped smoking for less than 10 yr was significantly lower (17.8 ± 4.5 and 17.8 ± 3.9, respectively) than values obtained in non-smokers and the group who had not smoked for more than 10 yr ( p