Antioxidant activity of serum ceruloplasmin and transferrin available iron-binding capacity in smokers and nonsmokers.

We investigated in 39 healthy smokers (20 female, 19 male) and 38 healthy nonsmokers (18 female, 20 male): the impact of smoking and smoking-related factors on the concentration of serum ceruloplasmin, transferrin, transferrin available iron-binding capacity (AIBC), and serum antioxidant activity (AOA); the relative contribution of serum ceruloplasmin and AIBC to serum AOA; the association and possible interactive effects of serum ceruloplasmin, AIBC, and smoking with serum AOA; and the relation of pulmonary function in healthy smokers to serum AOA, ceruloplasmin, and AIBC. We found that: as compared with healthy nonsmokers, healthy smokers had higher serum ceruloplasmin concentration, similar serum transferrin and AIBC concentration, and lower serum AOA; ceruloplasmin, AIBC, and smoking acted additively, accounting for about 60% of the variability of serum AOA; the impact of AIBC on serum AOA was significantly greater than that of ceruloplasmin; and pulmonary function in the smokers was not significantly related to serum AOA, ceruloplasmin, or AIBC. Our findings suggest that: serum AIBC has a greater role in serum AOA than has previously been attributed to it; suppression of the AOA of serum constituent(s) other than those we measured may account for the significantly lower serum AOA in healthy smokers than in healthy nonsmokers; and normal air flow in healthy cigarette smokers is unrelated to serum AOA, ceruloplasmin, or AIBC concentration.