Influence of age on bronchial mucociliary transport.

Mucociliary clearance was measured in 19 healthy non-smoking male subjects, aged between 21 and 69, by analysing the decrease in bronchial radioactivity of an aerosol of resin particles (mean diameter 7.4 +/- 1.5 micrometers) labelled with 99mTc. The mucociliary clearance was expressed as the percentage of radioactivity eliminated after 1 h. The measurements were made on two occasions with an average time lapse of 5 weeks. The intra- and inter-individual coefficients of variation were 15.6% and 41.5% respectively. The mucociliary clearance was significantly lower (P less than 0.05) (mean 21.8 +/- s.d. 7.8%) in the older subjects (greater than 54 years) than that observed (mean 34.1 +/- s.d. 14.1%) in the younger subjects (21 to 37 years). A significant negative correlation (r=-0.472, P less than 0.05) was obtained between the ages of the healthy subjects and their mucociliary clearance. However, the fact that the results varied considerably within each age group suggests that factors other than age may have an effect on the mucociliary clearance.