Long-term tobacco smoking and mucociliary clearance from the human lung in health and respiratory impairment.

The rate of mucociliary clearance was estimated from the removal of inhaled radioactive particles in 79 elderly subjects of whom 50 had healthy lungs and 29 had respiratory impairment that was obstructive in 13 and restrictive in 16. The 29 impaired subjects had on the average a faster clearance than the normal group, a difference that almost approached significance (5% level) at six hours after the inhalation of the aerosol. The obstructed subjects showed the fastest clearance with the restricted group intermediate between these and the normal group. No significant difference was found between the rates of clearance of smokers, nonsmokers, and exsmokers in either healthy or “diseased” groups.