Assessment of nasal mucociliary clearance (NMC) using methylene blue dye amongst bidi smokers, cigarette smokers and non-smokers.

Background: Nasal Mucociliary Clearance (NMC) system transports the mucus layer covering the nasal epithelium towards nasopharynx by ciliary beating at a frequency of 7-16 Hz. NMC is altered by septal deviations, upper respiratory infections, and drugs. Few studies have revealed significant depression of ciliary activity in smokers. We conducted this cross-sectional study to compare NMC and influence of smoking on NMC in adult non-smokers, cigarette-smokers and bidi-smokers using methylene blue dye test.

Materials and Methods: Our study included twenty non-smokers, twenty cigarette smokers and twenty bidi-smokers (20-40 years). A single drop of the methylene blue dye was placed in the anterior end of the inferior turbinate of the participants’ nasal cavity with the help of a nasal speculum.  After a period of fifteen minutes, the distance the methylene blue dye traversed inside the nasal cavity was gauged and recorded in millimetres with a nasal endoscope and a standard six-inch metal scale. NMC of the three groups were compared using Kruskal Wallis test.

Results: NMC was significantly reduced in bidi smokers (59.25 ± 12.38 mm; P < 0.05) in comparison to cigarette smokers (67 ± 5.58 mm) and non-smokers (68 ± 4.10 mm). Adjusted multivariate analysis revealed a significant association between NMC and bidi smoking; p < 0.05; 0.13(0.04-0.68), number of cigarettes/bidis smoked per day; p < 0.05; 0.33(0.07-0.99) and pack years; p < 0.05; 0.83(0.66-0.88).

Conclusions: NMC measurement is a simple and useful index for the assessment of effect of smoking on the ciliary activity of respiratory mucosa.