Original Article
IM PACT OF SM OKING ON ADULTS LUNG AGE AND VENTILATORY
FUNCTION
Omar Farouk Helal
Assist ant Professor, Physical Therapy Depart m ent , Facult y of Applied M edical Sciences, Um m Al Qura Universit y. KSA.
Background: Alt hough a large body of evidence exist s on t he ef fect of sm oking on lung age and pulm onary funct ion, m uch less at t ent ion has been dedicat ed t o using t hese ef fect s as an ef fect ive st rat egy in sm oking cessat ion.
Objective: The present st udy w as car ried out t o invest igat e t he im pact of sm oking on lung age and vent ilat ory funct ion in adult Saudi in order t o use t hese effect s in a fut ure st rat egy for sm oking cessat ion.
M et hods: Eight y one sm oker st udent s w it h t heir m ean age 23.88 ± 2.7 years w ere enrolled in t his st udy. Every st udent per form ed a vent i lat or y funct ion t est s in order t o m easure lung age, forced vital capacit y (FVC), forced expirat ory volum e at t he end of t he f irst second (FEV1), FEV1/ FVC rat io and peak expirat or y flow rat e PEFR. Results: The result show ed significant det eriorat ion in t he m ean value of FEV1, PEFR and t he est im at ed lung age and a non-significant difference in t he m ean values of FVC.
Conclusion: Sm oking has a significant effect on vent ilarot y f unct ion and det eriorat ing est im at ed lung age. KEYW ORDS:Sm oking, Lung Age, Vent ilat ory f unct ion.
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International Journal of Physiotherapy and Research
ISSN 2321- 1822
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Received: 24-02-2014 Accept ed: 11-03-2014
Published: 11-04-2014
ABSTRACT
INTRODUCTION
Address for correspondence: Dr. Om ar Farouk Helal, PT, Assist ant Professor, Physical Therapy
Dep ar t m en t , Facu l t y o f Ap pl i ed M edi cal Scien ces, Um m Al Qur a Un i v er si t y. KSA.
Email: dr.m on5@hot m ail.com
Int J Physiother Res 2014, Vol 2(2):453-59. ISSN 2321-1822
Peer Review : 24-02-2014
Cigarett e smoking is a major healt h problem t hat is responsible for a w ide range of prevent able healt h problem s t hroughout t he w orld. It is est im at ed t hat over t he next 20 t o 30 years, cigaret t e sm oking w ill result in 10 million deat hs annually on a w orldw ide basis, of w hich 70% w ill occur in developing count ries. 1
The World healt h organizat ion report ed t hat t obacco sm oking ki lled 100 m i llion people w orldw ide in t he 20t h cent ury and warned t hat it could kill one billion people around t he w orld in t he 21st cent ury. 2
Adolescent and t eenage sm oking has been st u d i ed w id el y, and i t h as b een f ou n d i n developing count ries t hat nearly one-half of
school st udent s w ho have reached t he age of 18 have already established t he habit of sm oking w it h som e degree of regularit y, and it is a rat her unrealist ic hope on t he part of adult s t o expect t hat children w ill abst ain unt il reaching t he adult approved age of decision. 3
M ATERIALS AND M ETHODS
St ud i es o f p u l m o n ar y f u nct i on am o n gasympt om at ic sm okers have dem onst rat ed t hat , as a group, t hey show significant im pairm ent of alm ost all paramet ers of lung funct ion, especially t ho se i n d icat in g ai r w ay o bst r uct i on s, as com pared t o m at ched groups of nonsm okers. 5
Acut e cigaret t e sm oke has a suppressive effect on t he num ber of eosinophi ls and several inflamm at ory cyt okines, possibly due t o t he ant i-inflam m at ory effect of carbon m onoxide. 6
In 2005, Selim and Al-Rushood 7
st at ed t hat according t o recent year for w hich official dat a are available, Saudi Arabia im port ed 36.5 m illion kg of t obacco, cost ing an est im at ed 979 m illion Saudi riyals (260.64 m illion US dollars) for a populat ion of about 15 m illion people. Lung cancer, a sm oking-relat ed disease, is a leading cause of cancer deat hs am ong Saudi m ales, suggest ing t hat cigaret t e sm oking is becom ing an import ant public healt h problem am ong m en in Saudi.
Sm ok i n g cessat io n is t h e o n ly ef f ect i v e t reat m ent , slow ing down t he accelerat ed decline in vent ilat ory funct ion. One st rat egy t o mot ivat e sm okers t o quit is t o assess w het her t hey have abno r m al lu ng f un ct ion, w hich i s a st rong independent risk fact or for chronic obst ruct ive p u lm o n ar y di sease (COPD), lu n g can cer, cardiovascular disease, st roke, and all-cause m ort alit y. 8
One w ay t o discuss abnorm al lung funct ion result s w it h pat ient s is t o use, t he lung age concept , w hich relat es a person’s current lung f unct ion, t o t he age at w hich his/ her lung funct ion w ould be considered norm al. Thus, an elevat ed lung age signifies poor lung funct ion as if t he lungs have aged beyond t he pat ient ’s chronological age. 9
Recent ly, Parkes, et al., 2010 and Kot z et al., 2011
1 0- 11 dem on st r at ed t h at u si n g l u ng age t o
com m unicat e lung funct ion t o sm okers in t he p r i m ar y car e set t in g en h ances sm o ki n g abst inence at one year, but t hese aut hors w ere not able t o dem onst rat e any negat ive im pact of norm al lung age.
Vent ilat ory funct ion t est s can provide im port ant cli n i cal in f o r m at io n , yet t h ey ar e vast l y u nd er used . They ar e d esigned t o pr ov id e object ive, quant ifiable m easures of lung funct ion
w hich are used t o evaluat e and m onit or disease t hat affect heart and lung, including airflow obst r uct io n, rest r ict i ve disorders, exer cise lim it at ion and bronchial hyperact ivit y and t he inform at ion obt ained from t hese t est s enable t he pract it ioner t o recognize im pairment , follow t he progress of disease, det erm ine pat ient s’ responses t o t herapy, and t o m onit or t he effect of environm ent al, occupat ional and t herapeut ic exposure. 12
Sm oking is a com m unit y healt h problem w hich unfort unat ely has becom e part of our yout h cul t u re. Th e su ccess of t he com m u ni t y i n t er v en t i on s fo r sm o k i ng cessat i o n an d changing sm oking at t it udes is t o know t he priorit y of sm oking as a public healt h problem and t o m ake ef for t s t o lim it and eradicat e sm oking.
So t he purpose of our st udy was t o clarify t he adverse effect s of sm oking on lung age and vent ilat ory funct ion in adult Saudi st udent s in order t o ut ilize it as an encouragem ent t ool for sm oking cessat ion.
Subjects:
One Hundred Healt hy, m ale, adult (aged 18 – 28 years) light sm okers for m ore t han t w o years w ere eligible for st udy ent ry. Subject s w ere excluded if t hey had diabet es m ellit us, blood pressure >160/ 95m m Hg, or if t hey w ere on m edicat ion, had any hist ory of part icipat ing in any regular exercise t raining for at least 4 m ont hs prior t o t he st udy, or w ere par t icipat ing in anot her clinical t rial.
Subject s w ere recruit ed via friends across t he Universit y and signed t he st andard inform ed consent form t o part icipat e in t he st udy following t he consent of t he Facult y Et hics Com m it t ee. We act ually st ar t t he st udy w it h 100 m ale healt hy subject s. All part icipant s w ere assessed u si n g a st r u ct u r ed p r e t est ed r espi r at o r y q uest i o nn air e t o o b t ain t h eir cl i ni cal an d ant hropom et ric dat a. Unfort unat ely 19 subject s dropped out and excluded from t he st udy.
Study materials:
consequent ly t he body mass index (BM I = weight “ kg” / height 2" m 2" ) was calculat ed. 13
2- Com put erized pulm onary funct ion t est ing (PFA) apparat us (Carello Quar k Cosm ed Sr I pulm onar y f unct ion t est -It aly) w as used t o evaluat e Vent ilat ory funct ion (FVC, FEV1, FEV1/ FVC, PEFR) and lung age am ong t he part icipat ed st udent s (Figure 1).
Fig. 1: Cosm ed PFT Apparat us.
Procedure:
Cosmed PFT apparatus preparation:
Calibrat ion of t he Cosm ed PFT apparat us was done daily before t he m easurem ent t akes place, t hen subject physical dat a [nam e, age (years), height (cm ), w eight (kg)] was ent ered t o allow t he Cosm ed PFT appar at us f low screen t o calculat e t he predict ed values.
Preparation of the subject:
The subject s t o be t est ed w ere light ly clot hed and inst ruct ed not t o eat before t he t est by 2 hours. The posit ion of t he subject s at t he t im e of t he t est was st anding posit ion, t hen learn t he subject what is m eant by t he various com m ands “ breat he nat urally”, “ t ake a deep breat h” and “ blow all t he air out ” was necessary explained before st art ing t he t est . The t est was explained t o each pat ient individually in sim ple t erm s and dem onst rat ed for t hem before applying it s steps. At t he beginning, subject ’s nam e, age, w eight , height , race and sex w ere recorded in t he com p ut er ized Cosm ed PFT ap parat us. The pat ient connect ed t o flow sensor, t hen nose clip was placed around t he subject ’s nose t o prevent ai r f ro m passi ng t h ro ugh t he no se du r i ng applicat ion, t hen he put a new m out hpiece int o his m out h; it was held by t he subject t eet h and enclosed firm ly by t he lips t o prevent air leakage.
The pat ient t hen breat hes few t im es norm ally before t he t est done.
The m aneuver was explained by t he inst ruct or t o t he part icipant s prior t o t est ing (breat he norm ally for several cycles, and t hen perform a m axim al inspirat ion, follow ed by a m axim um forced exhalat ion).
Subject s w ere asked t o breat he at first norm ally out of t he m out hpiece. The inst ruct or pressing t he st art-but t on at t he m om ent of t he subject is ready before st art t est . Then t he subject was asked t o t ake a slow and deep inspirat ion t o fill his lungs com plet ely w it h air and t hen expire (bl o w o u t ) as m u ch as h e can in t o t h e m out hpiece, w it h nose clip is on. In order t o com plet e t he FVC t est ing m aneuver and m eet t he accept abilit y and reproducibilit y crit eria, subject s m ust expel air forcibly and com plet ed in at least t hree at t em pt s six seconds each (Figure 2. A and B).
Fig. 2: Pulm onar y funct ion t est ing.
(A)
(B)
Statistical Analysis
St at ist ical analysis was conduct ed for t his st udy using SPSS soft ware version 16. All values w ere present ed as a m ean + st andard deviat ion (SD). Paired t-t est s w ere used t o assess any differences in spiromet ric dat a collect ed before and aft er t he exercise an d di f f er en ces w ere con si dered significant at p > 0.05.
Eight y-one sm oker st udent s from w ere enrolled in t his st udy. Their age ranged from 16 t o 25 years w it h a mean of 23.88 + 2.7 years t he height ranged from 158.00 cm t o 185.00 cm , w it h a m ean of 170.75 + 6.28 cm , and w eight ranged from 46.00 t o 94.00 kg, w it h a m ean of 72.32+ 11.53 kg and BM I ranged from 16.3 t o 33.12 kg/ m2 w it h a m ean of 24.82 + 3.88 kg/ m2. Table (1).
RESULTS AND TABLES
Table 1: General charact er ist ics of t he part icipat ing st udent s (m ean + SD).
Character M ean SD
Age (years) 21.53 1.6
W eight (Kg) 72.32 11.53
Height (cm) 170.75 6.28
BM I (Kg/ cm2) 24.82 3.88
Smoking duration
(years) 4.35 2.01
Cigarette number
(cig/ day) 12.8 5.73
Vent ilat ory funct ion, including (FVC, FEV
1 and
PEFR) and lung age w ere evaluat ed for all part icipant s.
Paired t-t est was applied t o t est t he hypot hesis t hat t here w ere non-signif icant dif ferences bet w een t he vent ilat ory funct ion (FVC- FEV
1
-FEV
1/ FVC -PEFR) and lung age values obt ained
from sm oker st udent s and t hose obt ained from predict ed m easures for norm al; nonsm oker st udent s.
The result s of t he st udy show ed t he effect of sm oking on vent ilat ory funct ion and lung age as app ear ed i n t he di f f eren ces b et w een t h e m easured values for sm okers and predict ed values for m at ched norm al subject s.
The result revealed t hat t here was a significant decrease in t he m ean of FEV1 values in sm okers’ st udent s as com pare w it h t he predict ed values of norm al, healt hy m at ched subject s, as F-value was (7.874) and p-value (0.006). Table (2) and Figure (3).
The result s show ed non-significant differences bet w een t he m ean values of FVC in sm okers’ st udent s as com pared w it h t he predict ed values of norm al, healt hy m at ched subject s, as F-value was (0) and p-value (0.989). Table (2) and Figure (3).
Table 2: The M ean, SD and ‘t ’ value w it h stat ist ical significance of t he evaluat ed param et ers of t he
st udent s.
Parameters
Smokers Students Values
Predicted
normal values t-value P-value
FVC 4.93 + 0.65 4.93 + 0.38 0 0.989* *
FEV1 4.22 + 0.29 4.44 + 0. 63 7.874 0.006*
PEFR 548.42 + 127 575.86 + 63.31 3.027 0.084* *
Lung age 23.88 + 2.7 21.51 + 1.7 44.871 0.000*
Level of si gni ficance at P<0.05. * = signifi cant * * = non-signif icant
As show n in t able (2) and figure (4) t here was non-significant difference in m ean value of PEFR (L/ m in) w hen com paring t he m easured values in sm okers, st udent s w it h t he predict ed values of norm al, healt hy m at ched subject s; F-value was (3.027) and p-value (0.084).
The result s show ed a signif icant dif ference bet w een t he m ean values of t he lung age values in sm okers’ st udent s as com pared t o t he act ual age values, as F-value was (44.871) and p-value (0.00). Table (2) and Figure (5).
Fig. 4: PEFR m ean values for sm okers and predict ed non-sm okers.
Fig. 5: Lung age m ean values for sm okers and predict ed non –sm okers.
DISCUSSION
This st udy was conduct ed t o assess t he im pact of sm oking on vent ilat ory funct ion and lung age in sedent ary sm oking st udent s. This st udy was conduct ed on 81 volunteer sm okers w ho agreed t o part icipat e in t he st udy, and was select ed random ly from a Universit y st udent s.
Forced expirat ory volum e in 1 sec. (FEV1) and forced vit al capacit y (FVC) are m easurem ent s of air forced out of t he lungs. These m easurem ent s are used t o gauge t he pulm onary funct ion. 14
Our st udy provides a conclusion about t he difference bet w een t he vent ilat ory funct ion and lung age o f sm oker st udent s com pared t o non-sm oker st udent s. The st udy proves t he associat ion of smoking w it h det eriorat ion of lung funct ions and lung aging.
Result s of vent ilat ory funct ion and lung age of sm o kers’ st u d en t s w er e co m p ar ed w it h p r ed i ct ed val u es f o r n o r m al m at ch ed non-sm okers and show ed significant difference in t he FEV1, PEFR and lung age bet w een t he sm oker st udent s’ values and predict ed norm al values. On t he cont rary; t he st udy revealed non-significant difference in FVC bet w een t he sm okers and non-sm okers.
Cigaret t e sm oking has been ident ified t o be t he m ost im por t ant det erm inant of vent ilat or y im pairm ent 15
. Sm oking im pairs t he grow t h of forced expirat ory volum e in one second (FEV1) in children16and cause an accelerat ed decline in
FEV1, in adult s. 15, 17
The concept of “ lung age” (t he age of t he average person w ho has an FEV1 equal t o t he individual) was developed as a way of m aking spirom et ry dat a easier t o underst and and also as a pot ent ial psychological t ool t o show smokers t he apparent prem at ure ageing of t heir lungs. 18
Abnorm al lung age is a clear m essage t hat t he lungs are undergoing accelerat ed det eriorat ion t hat w ould be slow ed if t he sm oker st opped19.
Lun g age is a w ay of co ncept u al i zi ng t h e det eriorat ion of lung funct ion and a w ay of expressing lung dam age rat her t han using m at hem at ical concept s of a percent age of t he expect ed value of FEV1 for height , age and gender. 20
The result s of t his st udy show ed clearly t hat v en t i lat o r y f un ct io n ; sp eci f i cal l y FEV1; significant ly det eriorat e in sm okers st udent s. Fur t her m ore; sm okers’ lungs show ed m ore advan ced age t han m at ch ed no r m al n on -sm okers. Walt er et al., 21 found t hat Adult
sm oker s exper i en ce f ast er lo n git u d in al pulm onary funct ion decline t han nonsm okers and t hat t his accelerat ed decline ret urns t o t he norm al rat e of aging-relat ed decline follow ing sm oking cessat ion, even if t he cessat ion is int erm it t ent . 21
The result s of t his st udy concerning vent ilat ory funct ion w ere previously support ed by a st udy by Jaw ed et al., 17 indicat ed t he associat ion of
sm oking w it h det eriorat ion of lung funct ions as w ell as t he num ber of cigaret t es sm oked/ day.These result s w ere furt her support ed by a cross-sect ional survey am ong t he 20 t o 40 years old sm okers t hat show ed associat ion of cigarett e sm oking w it h det eriorat ion in FEV1/ FVC rat io and t he onset of respirat ory com plaint s w hich was dosed dependent . 22
and t he non-sm okers of age 18-30 years.23
Viegi et al., 24 also show ed t hat t he prevalence
of pat hological pulm onar y funct ion t est s is significant ly higher in m ales and in subject s exposed t o act ive and/ or passive sm oking. . The reduct ion of FVC m ay be an early m arker of t he m orphological changes first occurring in t he sm all airways of subject s exposed t o sm oke. The decrease in FVC reflect s a sm all airw ay narrowing, wit h gas t rapping, det ermined by loss of elast ic load or airway t hickening w hereas t he d ecrease i n FEV1 r ef l ect s sm o ot h m uscl e cont ract ion in t he large airways. 25
Fur t h er m o re, t h e resu lt s of d et er io r at ed sm oker ’s PEFR in t his st udy w ere support ed by a st udy by W illem se et al., 26
t hat clearly found low er FVC, FEV1 and m id-expirat ory flow rat e (FEF25-75) in sm okers as com pared t o non-sm okers.26
Det eriorat ed vent ilat ory funct ion observed in sm okers can be furt her explained on t he basis of t he defensive lung reflex in response t o sm oking; result ing in narrow ing of t he airways and a consequent rise in airway resist ance. 27
Anot her explanat ion for abnor m al sm oker ’s vent i lat or y f unct ion is t hat t he sm oking of cigaret t es by hum ans is believed t o cause oxid at iv e st r ess b y sev er al m echan i sm s, including direct dam age by radical species and t he inflam m at ory response induced by sm oking. Oxidat ive st ress was found t o cause apopt osis and lung injury. 28,29
Sm ok i n g i n du ces an oxi dat i ve b ur d en b y dist urbing t he oxidant- ant ioxidant balance and leads t o cellular dam age in t he lungs. Oxidat ive st ress caused by cigaret t e sm oking can result in t he dest ruct ion of t he alveolar wall, leading t o ai r w ay en largem ent . M or eo ver, increased oxidat ive st ress can t rigger proinflam m at ory cyt okines, w hich are increased in t he lungs of sm okers. 30
Subst ant ial evidence suggest s t he accelerat ed decline of lung funct ion in cigaret t e sm okers’ result s f rom sm o ke-i ndu ced inf lam m at o r y p r ocesses. In f lam m at i o n b egi n s w i t h an increased num ber of m acrophages in t he first and second generat ion respirat ory bronchioles.
21
Airw ay epit helial cells (AEC) are im por t ant regulat ors of inflam m at ion in t he airway. They have a f unct ion in host defense and play a signif i cant rol e in air w ay inf l am m at ion by releasing NO, a pot ent ially im port ant m ediat or of airw ay inflam m at ion, as w ell as releasing ot her m ediat ors and recruit ing inflam m at ory cel ls. Cigaret t e sm oke i nt er f eres w it h and inhibit s t he norm al funct ion of AEC by a variet y of mechanisms. Some of t hese include decreases in t he level of exhaled NO, enhanced release of pro-inflam m at ory cyt okines, and inhibit ion of t he airway repair process.31
Exp osur e t o ci gar et t e sm oke act i vat es an inflam m at ory cascade in t he airway epit helium , result ing in t he product ion of a num ber of pot ent cyt okines and chem okines, w it h accom panying dam age t o t he l ung epit helium , incr eased perm eabilit y, and recruit m ent of m acrophages and neut rophils t o t he airway. 32
A posit ive associat ion bet w een pulm onar y sur fact an t an d ai r w ay di am et er h as b een described; surfactant prot eins w ere observed t o inhibit pulm onary inflam m at ion. Product ion of part icular surfact ant prot eins is inhibit ed by t obacco sm oking. 21
CONCLUSION
The result s of t he present st udy clarify t he d et er io r at i n g ef f ect s o f sm o k in g on l un g f unct ions and show ed t hat t he vent i lat or y funct ion of sm oker st udent s are significant ly low er t han t he predict ed vent ilat ory funct ion of age m at ch ed n on -sm o ker su bj ect s. Furt hermore; smoker lung tends t o be older t han age m at ched non-sm oker subject .
Acknow ledgment
Special t hanks t o Dr. Ashraf Abdelaal - Assistant Professor of Physical Therapy –Cairo Universit y, for his cont inuous support and encouragem ent .
Conflicts of interest: None
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