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Original Article
REVISTA PAULISTA DE MEDICIN AEnvironme ntal tobacco smoke e xposure
among non-smoking waite rs: me asure me nt of
e xpire d carbon monoxide le ve ls
Alcohol and drugs research unit (UNIAD),
Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil
a b s t r a c t
CON TEX T: Expo sure to enviro nmental to bacco smo ke is a health risk that is o f co ncern to patro ns and o f particular co ncern to emplo yees o f restaurants and bars.
OBJECTIVE: To assess enviro nmental to bacco smo ke expo sure (us-ing expired carbo n mo no xide levels) in no n-smo k(us-ing waiters befo re and after a no rmal day’s shift and to co mpare pre-expo sure levels with no n-smo king medical students.
DESIGN : An o bservatio nal study.
SETTIN G: Restaurants with mo re than 5 0 tables o r 1 0 0 places in São Paulo .
SUBJECTS: 1 0 0 no n-smo king restaurant waiters and 1 0 0 no n-smo k-ing medical students in São Paulo , Braz il.
M AIN M EASUREM EN TS: Levels o f expired carbo n mo no xide, mea-sured with a Smo kerlyser (Bedfo nt EC 5 0 Scientific), befo re and after a no rmal day’s wo rk.
RESULTS: W aiters’ pre-expo sure expired carbo n mo no xide levels were similar to tho se o f medical students, but after a mean o f 9 ho urs expo sure in the wo rkplace, median levels mo re than do ubled (2 .0 ppm vs. 5 .0 ppm, P <0 .0 0 1 ). Po st-expo sure carbo n mo no xide lev-els were co rrelated with the number o f tables available fo r smo kers (Kendall’s tau = 0 .2 , P <0 .0 0 0 1 ).
CON CLUSION S: Expo sure to enviro nmental to bacco smo ke is the mo st likely explanatio n fo r the increase in carbo n mo no xide levels amo ng these no n-smo king waiters. These finding s can be used to info rm the o ng o ing public health debate o n passive smo king .
KEY W ORDS: Passive Smo king . Restaurants. Carbo n Mo no xide. Braz il.
• Ro naldo Laranjeira • Sandra Pillo n • Jo hn Dunn
INTRODUCTION
Expo sure to enviro nmental to b acco smo ke is a health risk that is o f co ncern to patro ns and o f par-ticular co ncern to emplo yees o f restaurants and bars. In a review o f the literature, Siegel1
repo rted that lev-els o f enviro nmental to b acco smo ke were 1.6 to 2.0 times higher than tho se fo und in o ther types o f wo rk-place and 1.5 times higher than tho se in ho mes with at least o ne smo ker. Passive smo king has b een fo und to increase the risk o f develo ping lung cancer and ischemic heart disease.2 Co nseq uently, cities in
vari-o us cvari-o untries have intrvari-o duced laws that limit smvari-o k-ing to designated areas, b ut o utright pro hib itio n o f smo king in restaurants has b een less successful and has met o ppo sitio n fro m restaurateurs and the to -b acco industry.3,4 In 1995, the mayo r o f São Paulo
passed a municipal decree co mpletely banning smo k-ing in restaurants. Prio r to the implementatio n o f the decree we underto o k a study to measure levels o f expired carb o n mo no xide in waiters, b efo re and af-ter a no rmal wo rking day.
METHODS
Ethics
The pro cedures that fo llo w were in acco rdance with the ethical standards o f the co mmittee respo n-sible fo r human experimentatio n and with the Helsinki declaratio n o f 1975, as revised in 1983.
Setting
The survey was perfo rmed in São Paulo , Brazil,
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in July 1995 in a regio n near the center o f the city. Fifteen restaurants with mo re than 50 tab les (o r at least 100 places) were appro ached. These restaurants we re o pe n fo r lunch and dinne r: o n ave rage the y served 50 meals at lunchtime and 30 meals in the e ve ning. No ne o f the re staurants had se p arate d places fo r smo kers and no n-smo kers. Seven restau-rants refused to participate.
Subjects
One hundre d curre ntly no n-smo king waite rs were co ntacted perso nally in the wo rkplace and gave their co nsent to participate in the study. Smo king sta-tus was assessed b y asking the sub ject if he was a current smo ker. If he replied that he was no t, he was asked if he had ever smo ked, fo r ho w lo ng, numb er o f cigarettes smo ked per day and the time, in mo nths, since his last cigarette. No sub ject who had smo ked a cigare tte in the last mo nth was include d in the study.
Main Measurements
Befo re starting wo rk, each waiter was asked to respo nd to a sho rt questio nnaire that included ques-tio ns o n past smo king, expo sure to cigarette smo ke during the preceding 24 ho urs, and general questio ns ab o ut their health. Expired carb o n mo no xide level was measured using a deskto p Smo kerlyser (Bedfo nt EC 50 Scientific). In the restaurant, the measurement was perfo rmed in a place away fro m windo ws, do o rs, fans and air-co nditio ning vents. At the end o f the wo rking day the me asure me nt was re pe ate d. One hundre d curre ntly no n-sm o king m e dical stude nts acted as a co mpariso n gro up. They o nly pro vided o ne expired carb o n mo no xide measurement. Measure-ments were perfo rmed indo o rs, away fro m drafts and air currents.
Statistical Methods
No n-parametric statistical tests (Wilco xo n and Mann-Whitney) were used to analyze the data b e-c ause the e-c arb o n m o no xid e m e asure m e nts we re markedly and po sitively skewed. Data were no t trans-fo rme d due to the difficulty o f handling the large numb er o f zero values in the pre-expo sure gro ups. The differences b etween pre- and po st-expo sure car-bo n mo no xide levels were also po sitively skewed and included several zero values as well as a small num-b er o f negative values.
RESULTS
The mean age o f the waiters was 31.8 years (SD 9.6, range 18 to 54 years), 96% were men and they wo rked o n average six days a week. Fo rty-two per-cent were ex-smo kers who had q uit a median o f 2 years ago and 58% had never smo ked. Ninety-fo ur percent stated that their level o f do mestic expo sure to cigarette smo ke was zero , very lo w o r lo w, and 67% said that expo sure at wo rk was mo derate to very high. The medical students had a mean age o f 21 years (SD 2.2, range 17 to 29 years), 56% were men, 66% had never smo ked and 80% repo rted zero to lo w levels o f do mestic expo sure to cigarette smo ke. No sub -je c t had a p re - e xp o s ure c arb o n m o no xid e le ve l gre ate r than 8 p p m , whic h was c o nsid e re d to b e within the no rmal range fo r no n-smo kers. Amo ng the waite rs, a re pe at m e asure m e nt o f e xpire d carb o n mo no xide levels was made after a mean o f 9 ho urs (range 6 to 12 hrs) expo sure at the wo rkplace. Res-taurants were by and large reaso nably well ventilated, 37% had o pen windo ws, 72% o pen do o rs, 60% fans, 53% extracto r fans in the kitchens and 8% air-co ndi-tio ning.
Pre- and po st-expo sure carb o n mo no xide lev-els fo r the waiters are sho wn in Tab le. Fo llo wing epo sure at the wo rkplace, the median carb o n mo no x-ide levels mo re than do ub led. There was no co rrela-tio n between repo rted levels o f expo sure in the wo rk-place and po st-e xpo sure carb o n m o no xide le ve ls (Kendall’s tau = 0.07, P > 0.2) b ut a stro ng co rrela-tio n between the number o f tables available fo r smo k-ers and po st-expo sure carb o n mo no xide levels was fo und (Kendall’s tau = 0.2, P < 0.0001).
DISCUSSION
Our results sho w that after a perio d o f nine ho urs expo sure to cigarette smo ke in the wo rk envi-ro nment, median levels o f expired carb o n mo no xide
Table - Le ve ls of e xpire d carbon monoxide in non-smoking waite rs and me dical stude nts
Subjects M edia n ca rbon monox ide - ppm (interqua rtile ra nge)
Medical Students 2 .5 (1 .0 to 4 .0 ) (n = 1 0 0 )
W aiters: pre-expo sure 2 .0 (1 .0 to 3 .0 )† (n = 1 0 0 )
W aiters: po st-expo sure 5 .0 (3 .0 to 8 .0 )* (n = 1 0 0 )
ppm = parts per millio n; † = Mann-W hitney test sho wing ho mo g eneity o f medical students’ and waiters’ pre-expo sure carbo n mo no xide lev-els, P = 0 .1 8 , * = W ilco xo n test co mparing waiters’ pre- and po st-expo sure carbo n mo no xide levels, P < 0 .0 0 1 .
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mo re than do ub led amo ng no n-smo king waiters. Reviewing the literature, we were unable to find o ther studies in which expired carb o n mo no xide had been measured befo re and after expo sure in the wo rk-place. Mo st studies either measure enviro nmental levels o f carb o n mo no xide, nico tine and particulate matter o r saliva/serum co tinine levels. Jarvis et al3
perfo rmed a similar study amo ng 42 no n-smo king bar staff in Lo ndo n and Birmingham, UK, and fo und el-evated po st-expo sure levels o f saliva co tinine.
The elevated levels o f expired carb o n mo no x-ide fo und amo ng the waiters may no t b e entirely due to the inhalatio n o f c igare tte s m o ke , and o the r so urce s o f carb o n mo no xide must b e co nside re d. Expo sure to smo ke fro m kitchens, b arb ecues fires o r even fro m car exhaust fumes fro m o utside the res-taurant are all po ssibilities. Ho wever, the resres-taurants were well ventilated and mo st kitchens used hatches so that waiters did no t have to enter them. Only two o f the restaurants had barbecue facilities, which were fitted with exhaust flues. As already repo rted, 94% o f the waiters stated that do mestic expo sure to ciga-rette smo ke was zero , lo w o r very lo w, a repo rt that is sub stantiated b y the lo w pre-expo sure levels o f car-b o n mo no xide, which were co mparacar-b le with tho se o f the co ntro l gro up and within the no rmal range fo r no n-smo kers. We fo und a stro ng co rrelatio n between po st-expo sure expired carb o n mo no xide levels and the numb er o f tab les fo r smo kers b ut no t with the waite rs ’ o wn re p o rts o f e nviro nm e ntal c igare tte smo ke expo sure during the preceding 12 ho urs.
Per-hap s waite rs e xp o se d to high le ve ls o f c igare tte smo ke b eco me accusto med to this level o f expo sure and no lo nger think it excessive. Whatever the expla-natio n, the numb er o f tab les fo r smo kers is pro b ab ly a much mo re o bjective measure o f enviro nmental to -b acco smo ke expo sure.
Pro vided that o ther so urces o f carb o n mo no x-ide expo sure can b e co ntro lled, there are several ad-vantages to measuring levels o f expired carb o n mo n-o xid e , rathe r than saliva n-o r se rum c n-o tinine . The Smo kerlyser is q uick and easy to use, it is cheaper than perfo rming a series o f lab o rato ry assays, and is mo re acceptab le to the perso n giving the sample.
CONCLUSION
Altho ugh many restaurants have b o th smo king and no nsmo kking areas, this divisio n o nly pro -vides so me pro tectio n fo r the custo mer. Tho se who wo rk in restaurants co ntinue to b e expo sed to the harmful effects o f to b acco smo ke. If smo king is to b e co mpletely o utlawed in restaurants, o ne facto r that may pro mo te such a change is no n-smo king emplo y-ees suing their emplo yers fo r co mpensatio n b ecause o f the adve rse he alth e ffe cts suffe re d as a co nse -q uence o f o ccupatio nal expo sure to to b acco smo ke. The case o f Liesle Scho lem in Australia sho ws that such cases can have a significant impact o n smo ke-free po licies.1,5
Our results can b e used b o th to in-fo rm the deb ate o n passive smo king and as ammu-nitio n in the fight against smo king in pub lic places.
1. Go ttlieb M. Australian passive smo ker successfully brings suit against emplo yer. Wo rld Smo king Health 1992;17:13-5.
2. Hac kshaw AK, Law MR, Wald NJ. The ac c um ulate d e vid e nc e o n l u n g c a n c e r a n d e n vi ro n m e n ta l to b a c c o s m o ke . Br M e d J 1997;315:980-8.
3. Jarvis MJ, Fo ulds J, Feyerbend C. Expo sure to passive smo king amo ng bar staff. Br J Addict 1992;87:111-3.
4. Law MR, Mo rris JK, Wald NJ. Enviro nmental to bacco smo ke expo sure
REFERENCES
and ischaemic heart disease: an evaluatio n o f the evidence. Br Med J 1997;315:973-80.
5. Palin M, Yo ung M. The impact o f smo king litigatio n o n Australian wo rkplaces. To bacco Co ntro l 1994;3:78-9.
6. Scho field MJ. Smo king bans in restaurants: who is respo nsible and who needs pro tectio n? To bacco Co ntro l 1995;4:113-4.
7. Siegel M. Invo luntary smo king in the restaurant wo rkplace: a review o f emplo yee expo sure and health effects. JAMA 1993;270:490-3.
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r e s u m o
CON TEX TO: O ambiente expo sto à fumaça do cig arro traz g raves risc o s à sa úd e e p re o c up a ta nto o s e mp re g a d o re s q ua nto empreg a do s de resta ura ntes e b a res. N o enta nto , o s fuma ntes p a ssivo s c o rre m risc o s e le va d o s d e d e se nvo lve re m d o e nç a s canceríg enas, pulmo nares e cardíacas. Baseado s nestes parâmetro s e na experiência de países que sancio naram leis que pro íbem fumar o u restring em o fumar em áreas restritas e, antes de sancio nar leis municipais na cidade de São Paulo , dá-se a impo rtância de realiz ar este estudo .
OBJETIVO: Avaliar a expo sição à fumaça de cig arro no ambiente de trabalho (através da medida do nível de mo nó xido de carbo no ) em g arço ns não fumantes, antes e depo is do expediente de trabalho , e c o mp a ra r o s níve is p ré -e xp o siç ã o c o m o s d e e stud a nte s universitário s não fumantes.
TIPO DE ESTUDO: Estudo o bservacio nal.
LOCAL: Restaurantes co m mais de 5 0 mesas o u 1 0 0 assento s, to do s lo caliz ado s em São Paulo .
PARTICIPAN TES: A amo stra é co nstituída po r 1 0 0 g arço ns não fumantes e 1 0 0 estudantes não fumantes.
VARIÁV EIS ESTUDADAS: O níve l d e mo nó xid o d e c a rb o no expirado fo i medido co m um aparelho Smo kerlyser (Bedfo nt EC 5 0 Scientific), antes e depo is do expediente de cada g arço m.
RESULTADOS: O s níveis pré-expo sição de mo nó xido de carbo no expirado fo ram semelhantes entre o s g arço ns e o s estudantes, mas apó s uma média de 9 ho ras no lo cal de trabalho , o nível mediano entre o s g arço ns fo i mais que o do bro (de 2 ,0 ppm para 5 ,0 ppm, P < 0 ,0 0 1 ). O s níveis pó s-expo sição de mo nó xido de carbo no co rrelacio naram co m o número de mesas dispo níveis para fumantes (Kendall’s tau = 0 ,2 , P < 0 ,0 0 0 1 ).
CON CLUSÃO: A expo sição à fumaça de cig arro no ambiente de trabalho é a explicação mais pro vável para este aumento no nível de mo nó xido de carbo no expirado entre o s g arço ns. Estes achado s po dem ser utiliz ado s para direcio nar o debate so bre fumo passivo e a saúde pública.
PALAVRAS-CHAVE: Fumante passivo . Restaurantes. Mo nó xido de carbo no . Brasil.
Ronaldo Laranje ira, MD, PhD. Co o rdinato r - UNIAD – Alco ho l and drugs research unit. Universidade Federal de São Paulo /Esco la Paulista de Medicina, São Paulo , Brazil.
Sandra Pillon. Research Nurse - UNIAD – Alco ho l and drugs research unit. Universidade Federal de São Paulo /Esco la Paulista de Medicina, São Paulo , Brazil.
John Dunn. Co o rdinato r - UNIAD – Alco ho l and drugs research unit. Universidade Federal de São Paulo /Esco la Paulista de Medicina, São Paulo , Brazil.
Source of funding: This study was funded by the municipal co uncil o f São Paulo
Conflict of inte re st: No t declared
Last re ce ive d: 30 March 2000
Acce pte d: 20 April 2000
Addre ss for corre sponde nce :
Ro naldo Laranjeira
UNIAD, Departamento de Psiquiatria, Universidade Federal de São Paulo / Esco la Paulista de Medicina.
Rua Bo tucatu, 740
São Paulo /SP - Brasil - CEP 04023-900. E-mail: laranjeira@ psiquiatria.epm.br
p u b lis hin g in fo r m a t io n
