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The LaryngoscopeVC 2012 The American Laryngological,Rhinological and Otological Society, Inc.

Effect of Passive Smoking on the Ultrastructure of the NasalMucosa in Children

Samy Elwany, MD, FACS; Ahmed Aly Ibrahim, MD; Zeyad Mandour, MD; Iman Talaat, PhD

Objectives/Hypothesis: Passive exposure to cigarette smoke has been implicated in a number of respiratory childhooddisorders. Most studies concerning smoking were directed to its carcinogenic effect on the lungs. However, the effects ofsmoking on nasal respiratory mucosa have not been widely studied. The aim of the present study was, therefore, to study theultrastructural changes in the nasal mucosa of a pediatric population exposed to passive smoking.

Study Design: The study included 20 children between the ages of 5 and 11 years, who were scheduled for tonsillec-tomy and at the same time had a positive history of prolonged exposure to household passive smoke. Another 10 childrenwith a negative household smoking history were included as a control group. All children were nonatopic and with a negativefamily history of allergy. None of them had adenoids or infective rhinosinusitis.

Methods: At the time of surgery, a 1-mm3 biopsy was taken was taken from the lower border of the inferior turbinate.The specimens were processed and examined with electron microscopy

Results: Examination of the nasal mucosa showed several ultrastructural changes. These included patchy loss of cilia,generalized loss of cilia, squamous metaplasia, hyperplasia of goblet cells and seromucinous acini, and vascular congestion.More severe changes were observed with longer passive exposures to cigarette smoke. The study did not disclose any evi-dence of ongoing allergic reaction or neoplastic transformations.

Conclusions: Children exposed to passive cigarette smoke may develop several structural changes in the respiratorynasal mucosa with subsequent negative effects on its ciliary activity and mucociliary function. As a result of these effects,defense mechanisms of the nose may be ruined or lost, and those children may develop persistent sinonasal infections. Expo-sure of these children to passive smoking for longer periods of time may also induce other significant changes that were notdetected in the present study.

Key Words: Passive, smoking, nasal mucosa, transmission, electron microscopy.Level of Evidence: 2c

Laryngoscope, 122:965–969, 2012

INTRODUCTIONPassive smoking is the inhalation of smoke, called

secondhand smoke or environmental tobacco smoke,from tobacco products used by others. A complex mix-ture of chemicals is generated from the burning andsmoking of tobacco. As a passive smoker, the nonsmokerbreathes sidestream smoke from the burning tip of thecigarette and mainstream smoke that has been inhaledand then exhaled by the smoker.

Passive exposure to cigarette smoke has been impli-cated in a number of respiratory childhood disorders,and there is conclusive evidence that children are at aparticular risk from adults’ smoking.1,2 Vinke et al.3

reported that passive smoking might cause an allergiccell infiltrate in the nasal mucosa of nonatopic children.

Nageris et al.4 reported the deleterious effect of smokingon olfaction in children.

Most studies concerning smoking were directed toits carcinogenic effect on the lower respiratory tract.However, the effects of smoking on nasal respiratory mu-cosa have not been widely studied, even though the noseis one of the most exposed organs.5 In fact, to date nostudy described the effect of passive smoking on thestructure of the nasal mucosa of children. The aim of thepresent study was, therefore, to study the ultrastruc-tural changes in the nasal mucosa of a pediatricpopulation exposed to passive smoking. Transmissionmicroscopy was used for this purpose.

MATERIALS AND METHODSThe study included 20 children, between the ages of 5 and

11 years, who were scheduled for tonsillectomy and at the sametime had a positive history of exposure to household passivesmoke. The duration of passive exposure to smoke wasrecorded. Exposure to passive smoking was determined using aparental questionnaire about household smoking.

A validated objective measure of smoke exposure wasdetermined by measuring the urinary cotinine: creatinine ratioin all children whose parents confirmed household smoking.The children were divided arbitrarily into two groups accordingto their ages. Another 10 children with negative household

From the Department of Otolaryngology (S.E., A.A.I., Z.M.) andDepartment of Pathology (I.T.), Alexandria Medical School, Alexandria,Egypt.

Editor’s Note: This Manuscript was accepted for publicationJanuary 19, 2012.

The authors have no funding, financial relationships, or conflictsof interest to disclose.

Send correspondence to Samy Elwany, MD, 4 Kfr Abdou Street#605, Alexandria, Egypt. E-mail: [email protected]

DOI: 10.1002/lary.23246

Laryngoscope 122: May 2012 Elwany et al.: Passive Smoking in Children

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smoking history were included as a control group. All childrenwere nonatopic and with a negative family history of allergy.None of them had adenoids or infective rhinosinusitis. Informedconsent was obtained from all of the patients’ parents for inclu-sion in the research, and the committee of ethics approved thestudy.

At the time of surgery, a 1-mm3 biopsy was taken from thelower border of the inferior turbinate, 1.5 cm behind its anteriorend. The specimens were examined with the transmission elec-tron microscope (TEM).

Preparation of the Specimens for TEMThe specimens were immediately fixed in Karnovsky’s fix-

ative at 4�C for 4 hours. They were then post-fixed in 1%osmium tetroxide and dehydrated in graded alcohol solutions.The specimens were then impregnated with araldite (CY212)using propylene oxide as intermediate solvent. The specimenswere finally polymerized at 60�C in embedding capsules. Ultra-thin sections were cut with an ultramicrotome, stained with 4%uranyl acetate and Reynold’s lead acetate, and examined undera Hitachi H-600 (Hitachi Ltd., Tokyo, Japan) high-resolutiontransmission electron microscope. The pathologist was blindedto the specimens.

The ultrastructural changes were considered true if theyexisted in more than 50% of the examined sections. The obser-vation was considered mild if it existed in 50% to 60% of theexamined sections, moderate if it existed in 60% to 80% of theexamined sections, and severe if it existed in more than 80% ofthe sections. The ultrastructural changes were graded as fol-lows: 0 ¼ absent, 1 ¼ mild, 2 ¼ moderate, 3 ¼ severe.

Statistical analysis was performed using SPSS for Win-dows version 15 (SPSS, Inc., Chicago, IL). Student t test andSpearman correlation coefficient were used for data analysis.

RESULTSThe nasal mucosa of children exposed to passive

smoking showed several fine departures from normal.The frequency of the observed changes is shown in TableI. Several ultrastructural changes were observed. Theseincluded: epithelial changes (45%), hyperplasia of gobletcells (30%), hyperplasia of seromucinous glands (40%),and vascular congestion (45%). Patchy loss of cilia wasthe most common epithelial pathology in our series(35%). On the other hand, widespread loss of cilia wasobserved in a single case, and areas of squamous meta-plasia were seen in another case. The control group, onthe other hand, did not show any of the above-mentionedchanges.

The changes tended to be more severe withincreased duration of exposure to cigarette smoke (TableII), and there were significant differences between thetwo groups regarding the duration of exposure to smoke(t ¼ 9.7575, P < .001) and severity of the changes in themucosa (t ¼ 2.2000, P < .05). There was a positive rela-tionship between the two variables (r ¼ 0.64608).Detailed descriptions of the ultrastructural changes areshown below. The electron microscopic pictures are rep-resentative samples of these changes.

EpitheliumThe epithelium showed areas of patchy and wide-

spread ciliary loss (Figs. 1B and 2A). Goblet cells werefrequently hyperplastic and distended with mucigengranules (Fig. 2A). Areas of squamous metaplasia wereseen in a single case (Fig. 2B). The basal lamina (Fig.2B) appeared as a thin membrane separating the epithe-lium from the lamina propria. The lamina propriashowed fine irregularly arranged collagenous fibers, butthere were no areas of subepithelial edema. No eosino-phils were seen in the lamina propria. Intact plasmacells and mast cells were occasionally seen, and they didnot show any evidence of being involved in any antigenantibody reactions.

Seromucinous GlandsMany seromucinous acini appeared hyperplastic

and distended with secretory granules (Fig. 3). The glan-dular cells showed numerous mitochondria andabundant granular endoplasmic reticulum with dis-tended cisternae indicating increased secretory activity.

TABLE I.Frequency of the Ultrastructural Features According to Age

Groups.

Group A,5–8 Years

Group B,9–11 Years

Ultrastructural Feature No. (%) No. (%)

Patchy loss of cilia 3 (30) 4 (40)

Widespread loss of cilia 0 (0) 1 (10)

Squamous metaplasia 0 (0.0) 1 (10)

Goblet cell hyperplasia 3 (30) 3 (30)

Seromucinous acini hyperplasia 3 (30) 5 (50)

Congested capillaries and sinusoids 4 (40) 5 (50)

TABLE II.

Duration of Exposure to Smoke and Scores of the UltrastructuralChanges in the Two Groups.

PatientNo.

Group A Group B

Duration ofExposure to

Smoke(Months) Score

Duration ofExposure to

Smoke(Months) Score

1 63 0 125 3

2 69 1 113 0

3 63 0 119 2

4 89 2 113 3

5 66 0 101 3

6 70 0 107 1

7 82 2 99 0

8 52 0 121 2

9 74 1 103 0

10 67 0 118 3

Mean(SD)

69.50 (10.36)* 0.60 (0.84)† 111.90 (9.02)* 1.70 (1.34)†

*The difference is highly statistically significant (P < .001).†The difference is statistically significant (P ¼ .0411).‡Correlation coefficient (r) between the duration of exposure to

passive smoking and the scores of the ultrastructural changes ¼ 0.64608.SD ¼ standard deviation.


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Blood VesselsThe capillaries and venules appeared congested and

dilated (Fig. 4). There were no pericapillary edemas, andthe interendothelial junctions were intact and not widelyopened. The endothelial cells showed few small pinocy-totic vesicles.

DISCUSSIONCigarette smoke is a mixture of pharmacologically

active, toxic, mutagenic, and carcinogenic substances.6

Secondhand smoke includes smoke from the burning endof a cigarette, pipe, or cigar as well as the smokeexhaled from the lungs of smokers. It is involuntarilyinhaled, and it lingers in the air hours after cigaretteshave been extinguished. Secondhand smoke is especiallyharmful to young children, and it may cause many ofthe diseases induced by direct smoking.7

As the nose lies at the entrance of the respiratorytract, it is expected that pathological changes in thenasal mucosa may occur secondary to exposure to director passive cigarette smoke. However, comprehensivereview of the literature has shown only a few studiesaddressing this issue in spite of its obvious importance.8

Fig. 1. Patchy loss of cilia. Discrete areas of missing cilia (star)are seen surrounded by areas with normal cilia (arrow). Microvilli(arrowheads) are still seen in areas with lost cilia (�5,000).

Fig. 2. (Panel A) Wide areas of ciliary loss are seen (arrow). Hyperplastic goblet cell (g) is seen within the columnar epithelia cells (c)(�2,500). (Panel B) Squamous metaplasia. The ciliated columnar cells are replaced with squamous cells (S) (�2,500).

Fig. 3. A hyperplastic hyperactive glandular acinus. The acinarcells are distended with numerous mucigen granules (m) (�6,100).


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The present study is probably the first transmissionelectron microscopic report about the effect of passivesmoking on the respiratory nasal mucosa of children.

In the present study, several ultrastructuralchanges were observed in the respiratory nasal mucosaof children passively exposed in a regular way to ciga-rette smoke. Congestion of the mucosa was the mostcommon observation in our series, followed by epithelialchanges and hyperplasia of the mucus-producing ele-ments in the nasal mucosa.

Congestion of the capillaries and venous sinusoidswas an important feature in our series. However, theinterendothelial gaps of the capillaries remained intact,and the endothelial cells showed few pinocytotic vesicles,which are normally responsible for fluid transport acrossthe endothelial cells. These findings are contrary towhat have been reported in patients with allergic rhini-tis,9 and at the same time explains the absence ofpericapillary and subepithelial edema, which are com-monly described in allergic cases.10

The changes in the respiratory nasal mucosaappeared to be directly proportionate to the duration ofpassive exposure to smoke. As the duration of exposureincreased, the ciliary loss tended to be more widespreadand areas of squamous metaplasia and total loss of ciliastarted to appear. In fact, the observed deleterious effectof passive smoking on nasal cilia, in the present study,confirms the report of Agius et al.,11 who found thatsmoking decreased ciliary beat frequency. It also con-firms the study of Atef et al.,8 who found that passivesmoking had a negative impact on cilia regeneration fol-lowing functional endoscopic sinus surgery.

Hyperplasia of goblet cells and seromucinous aciniwere other notable features, especially in cases withpatchy loss of cilia. On the other hand, goblet cells wereabsent in areas showing squamous metaplasia. Rogerset al. reported similar secretory cell hyperplasia in thebronchial mucosa.12 This hyperplasia of mucin-producingcells is obviously a protective mechanism to wash outnoxious particles and protect the delicate nasal mucosa.

However, although tobacco smoke may increase mucusproduction of the respiratory mucosa, it may also changeits physical properties as reported by Jeffery and Reid,13

who found that smoking did change the glycoproteincontents of bronchial mucus and degraded its visco-elastic properties.

Vinke et al.3 mentioned that passive smoking mightcause an allergic cell infiltrate in the nasal mucosa ofnonatopic children. Our findings, however, did not sup-port this observation for several reasons. First, we foundonly few plasma cells, eosinophils, and mast cells. Theseare the cells that are typically involved in allergic reac-tions, and their scarcity indicates absence ofimmunological stimulation. Second, the mast cells wereintact and fully granulated, unlike the degranulated his-tamine-releasing mast cells in allergic cases.14 Third,the gaps between the endothelial cells of capillaries wereintact and narrow, and the pinocytotic vesicles were few.Consequently, there was no edema under the epitheliumand around the capillaries. Allergic cases, on the otherhand, characteristically show mucosal edema secondaryto widening of the interendothelial gaps and the pres-ence of large numerous pinocytotic vesicles transportingfluid across the endothelial cells.9

The present study showed that passive tobaccosmoking might disturb the nasal defense system byparalyzing mucociliary clearance and changing its secre-tory components. Similar changes have been reported inthe lung and bronchi.15 As a result of these effects,active and passive smokers may suffer from a higher fre-quency of sinonasal infections.16 On the other hand, thepresent study did not show any evidences of ongoing al-lergic reactions, indicating that the observed changesare due to the direct detrimental effect of the noxiousmaterials contained in the smoke on the nasal mucosa.The present study again did not show any evidence ofneoplastic transformations.

CONCLUSIONChildren exposed to passive cigarette smoke may

develop several structural changes in their respiratorynasal mucosa with subsequent negative effects on its cil-iary activity and mucociliary function. As a result ofthese effects, defense mechanisms of the nose may be ru-ined or lost, and those children may develop persistentsinonasal infections. Exposure of these children to pas-sive smoking for longer periods of time may also induceother significant changes that were not detected in thepresent study.

BIBLIOGRAPHY

1. Cook D, Strachan D. Health effect of passive smoking—summary of effectsof parental smoking on the respiratory health of children and implica-tions for research. Thorax 1999;54:357–366.

2. Report of the Scientific Committee on Tobacco and Health. London, UK:Department of Health; 1988.

3. Vinke J, Denjan A, Severijnen L, Fottens J. Passive smoking causes an al-lergic cell infiltrate in the nasal mucosa of in-atopic children. Int JPediatr Otolaryngol 1999;51:73–81.

4. Nageris B, Hadar T, Hansen M. The effect of passive smoking on olfactionin children. Rev Laryngol Otol Rhinol (Bord) 2002;128:89–91.

5. Dessi P, Sambuc R, Movlin G, Iedoray V. Effect of heavy smoking on nasalresistance. Acta Otolaryngol (Stockh) 1994;114:305–310.

Fig. 4. A dilated capillary. The endothelial cells (e) are together inclose contact and the interendothelial junctions (arrowhead) arenarrow. Pericytes (p) are seen around the capillaries, but there isno pericapillary edema (�4,500).


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6. Usenius T, Karja J, Collan Y. Squamous cell carcinoma of the tongue inchildren. Cancer 1987;60:236–239.

7. Samet JM. Secondhand smoke: facts and lies. Salud Publica Mex 2008;50:428–434.

8. Atef A, Abo Zeid I, Qotb M, Gad El Rab E. Effect of passive smoking onciliary regeneration of nasal mucosa after functional endoscopic sinussurgery in children. J Laryngol Otol 2009;123:75–79.

9. Toppozada H, Talaat M. Tunica propria in chronic allergic rhinitis. ORL JOtorhinolaryngol Relat Spec 1976;38:86–98.

10. Elwany S, Bumsted R. Ultrastructural observations on vasomotor rhinitis.ORL J Otorhinolaryngol Relat Spec 1987;49:199–205.

11. Agius A, Smallman L, Pahor A. Age, smoking and ciliary beat frequency.Clin Otolaryngol 1998;23:227–230.

12. Rogers DF, Jeffery PK. Inhibition of cigarette smoke induced airway secre-tory cell hyperplasia by indomethacin, dexamethasone, prednisolone, orhydrocortisone in the rat. Exp Lung Res 1986;10:285–298.

13. Jeffery PK, Reid LM. The effect of tobacco smoke, with and without phenl-methyloxadiazole (PMO) on rat bronchial epithelium; a light and micro-scope study. J Pathology 1981;133:341–359.

14. Toppozada H, Talaat M. Human nasal epithelium and cellular elements inchronic allergic rhinitis.ORL JOtorhinolaryngol Relat Spec 1975;37:333–343.

15. Janice A, Kenneth B. Effect of cigarette smoke on epithelial cells of the re-spiratory tract. Thorax 1994;49:825–834.

16. Benninger MS. The impact of cigarette smoking and environmentaltobacco smoke on nasal sinus disease: a review of the literature. Am JRhinol 1999;13:435–438.


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