Respiratory abnormalities among male foundry workers in central Taiwan

Transcription

1 Occup. Mod. Vol. 49, No. 8, pp , 999 Copyright O 999 Uppicott Williams & WllWs for SOW Prited I Great Britai. All rights reserved /99 Respiratory abormalities amog male foudry workers i cetral Taiwa H.-W. Kuo,* C.-L. Chag,* W.-M. Liag* ad B.-C. Chug* *Istitute of Evirometal Health, Chia Medical College, Taichug, Taiwa; *Provicial Feg-Yua Hospital, Taiwa Provicial Health Departmet, Taiwa The objectives of this study were to determie the relatioship betwee exposure levels ad respiratory abormalities, to measure FVC ad FEV, chages per year based o work duties ad to Ivestigate the prevalece of ad factors related to peumocoiosis. A total of 58 male workers from 5 iro foudries i cetral Taiwa were ivestigated. First, workers' respiratory symptoms were categorized usig a modified America Thoracic Society (ATS) questioaire ad the were verified by physicia's examiatio. Next, pulmoary fuctio tests were performed icludig: forced vital capacity (FVC), forced expiratory volume i oe secod (FEV^ ad forced expiratory flow rate. A chest radiograph was used to diagose peumocoiosis accordig to ILO criteria. Furace workers were foud to have the highest prevalece of chroic phlegm, thoracic disorders ad chroic brochitis. I geeral, smokers had a higher prevalece of respiratory symptoms as compared with o-smokers. Pulmoary fuctio abormalities ad peumocoiosis were closely liked to smokig ad work duratio. After adjustig for age, height ad smokig there was a sigificat decrease based o work duratio i FVC ad FEV, for furace ad mouldig workers compared with after-processig ad admiistrative workers. The overall prevalece of peumocoiosis was 8.8%, highest amog furace (6.%) ad after-processig workers (.4%) ad lowest amog admiistrative workers (.5%). Usig multiple logistic regressio, the risk of developig peumocoiosis (as compared with the admiistrative workers) for furace workers was highest (8.98 times greater risk), followed by after-processig workers (6.77 times greater risk) ad mouldig workers (5.4 times greater risk). Prologed exposure to free silica, ad smokig habits, ca result i respiratory abormalities amog foudry workers. Key words: Foudry workers; lug fuctio; male; peumocoiosis; respiratory symptoms. Occup. Med. Vol. 49, , 999 Received 8 February 999; accepted i fial form 5 Jue 999 This itudy was supported by a grat from the Istitute of Occupatioal Safety ad Health, Coucil of Labor Attai, Executive Yua, ROC, IOSH 8-H. INTRODUCTION Foudry processes produce may hazardous chemicals that are released ito the workplace ad may have damagig effects o the health of the workers, such as respiratory abormalities, icludig silicosis that results from exteded exposure. These hazardous chemicals iclude dipheyl methae diisocyaate, pheol formalde- Correspodece to: H.-W. Kuo, Istitute of Evirometal Health, Chia Medical College, No. 9, Hsueh-Shl Road, Taichug, Taiwa, ROC. Tel: (+886) 4-5^76 ext. ; Fax: (+886) 4-99; wukuoomail.cmc.edu.tw. hyde ad their decompositio products as well as silicacotaiig particulates. l ~ Basic foudry operatios iclude the creatio of a sad-based mould, metal meltig ad pourig, cast shakeout ad fiishig ad sad reclamatio. Because workers i differet areas are exposed to differet particle sizes ad cocetratios, some foudry jobs are more hazardous tha others. Such miute particles are formed by melted metals which coagulate i the air due to the temperature gradiet outside the furace. Without proper persoal protective equipmet, these particles ca be easily ihaled ad have damagig effects o respiratory fuctio. Dowloaded from o July 8

2 5 Occup.Med.VW. 49, 999 Malmberg 4 reported a poor correlatio betwee lug fuctio ad radiographic chages idicatig silicosis. Cofoudig factors (such as age, smokig, worker turover ad job trasfers withi the foudry) make it difficult to fid a clear relatioship betwee the health effect o exposed workers ad airbore dust cocetratios. Koskela 5 coducted a retrospective cohort study of foudry workers, metal product workers ad electrical workers. Koskela reported that foudry workers had a higher rate of chroic brochitis tha the correspodig groups of metal product ad electrical workers. The prevaleces of all diagosed lug diseases were the highest (4%) at the high exposure level, the secod highest (6%) at the medium exposure level ad the lowest at the light exposure levels. Ostiguy 6 coducted a cross-sectioal ad logitudial survey of 494 workers i a copper refiery. Ostiguy foud that the prevalece of chroic obstructive pulmoary diseases (COPD) was 5%, small airway dysfuctio (SAD) was 7%, but these did ot differ from the cotrol populatios. The data show that low-level, log-term exposure to metal dusts, gases ad foudry fumes does ot ecessarily cause respiratory dysfuctio. I a 985 study of 78 foudry workers, Johso 7 reported the prevalece of peumocoiosis to be 4.8%. I 987, Myers et al. foud that.% tested positive for peumocoiosis amog South Africa foudry workers. For those with 5 or more years of foudry work experiece, the prevalece icreased to 8%. Three major studies have bee coducted i Taiwa evaluatig health effects o foudry workers. The first, i 985, by Mao et al. 8 focused o 79 workers from oe foudry ad reported their respiratory dust cocetratios varied sigificatly (.- mg/m ) depedig o workplace locatio. About % of the workers were foud to have lug fuctio abormalities. A secod study i 99 by Li 9 ivestigated 9 workers from 6 foudries ad foud that.7% of workers had lug fuctio abormalities ad 6.9% had silicosis. Respiratory dust cocetratios raged from oe detected (ND) to 7.5 mg/m, with a geometric mea of.76 mg/m. The third study was coducted by Taia Hospital o 7 workers from foudries, ad foud that 9.7% had lug fuctio abormalities ad.7% had silicosis. However, these studies lack data pertaiig to respiratory symptoms, ad the foudries ivestigated are ot represetative of foudries throughout Taiwa. The curret study was performed to determie the relatioship betwee exposure levels ad respiratory abormalities, to measure FVC ad FEV chages per year based o work duties, ad to ivestigate the prevalece of ad factors related to peumocoiosis. MATERIALS AND METHODS Most of the factories ivestigated i this study were relatively small-scale ad employed fewer tha workers. I compariso with curret iteratioal stadards, workig coditios icludig clealiess ad quality of equipmet ad facilities were geerally poor. The foudry workers studied were predomiatly male, had a average age of 4 years ad had completed a low level of educatio. Sice duties performed by furace ad mouldig workers require a high level of skill, work duratios teded to be log ad ofte occupied much of their adult lives. A total of 58 male workers from 5 govermet-licesed foudries i cetral Taiwa were icluded i this study. Oe hudred ad twety-five female workers were excluded from the study sice about 9% were ivolved i admiistratio ad this would affect compariso of the other groups. Workers were classified ito four groups based o exposure to airbore dust cocetratios: mouldig (high-exposure group), furace (medium-exposure group), after-processig (low-exposure) ad admiistrative (cotrol group). Due to the ueve geder distributio betwee the groups, wome were excluded from the study. I order to avoid the 'healthy worker effect', iformatio was take regardig their idividual workig histories. Evirometal samplig was coducted i 5 foudries (5 foudries were uwillig to co-operate). Area samplig was performed to measure total airbore dust cocetratios, of which the mouldig area tested highest (5.96 mg/m ), followed by the furace area (.74 mg/m ), ad after-processig (.6 mg/m ). Cocetratios were cosistet based o persoal samplig, mouldig workers tested highest (5.55 mg/m ), followed by furace (.89 mg/m ), ad after-processig workers (.77 mg/m ). Total airbore dust cocetratios i the admiistrative area were comparably low (<. mg/m ) for both area ad persoal samplig. Average respirable dust cocetratio" was.89 mg/m for the mouldig group,.76 mg/m for the furace group ad.7 mg/ m for the after-processig group. A modified versio of a America Thoracic Society (ATS) questioaire was used to iterview subjects. Questios ivolved employmet history, respiratory symptoms (as defied by the ATS) (Table ), health status ad use of persoal protective equipmet. After completig the questioaire, all workers were examied by a qualified occupatioal physicia to verify ay reported respiratory symptoms. Dummy variables regardig circulatory system ad digestive system symptoms were icluded to improve the reliability of the questioaire. The ATS criterio classifies respiratory symptoms i terms grades: grade is ormal ad grades ad above are abormal. Sice there were very few subjects i grades ad 4, oly grades ad were icluded; these were combied so that the study comprised just two groups, abormal ad ormal. Lug fuctio tests were performed usig a Fukada HI-96 Spirometer. Variables icluded vital capacity ad forced expiratory flow rate at 5%, 5% ad 75% of the FVC curve. Accordig to the ratio betwee FEVj ad FVC, subjects were classified as ormal, obstructed, restricted or mixed. Subjects were istructed to refrai from smokig, excessive eatig ad use of vasodilators or brochodilators o the day of testig. Stadard procedures for operatig the spirometer were give ad a demostratio was performed. Prior to testig, a -litre Dowloaded from o July 8

3 H.-W. Kuo ef a/.: Respiratory abormastles of fowidry workers 5 syrige was used to calibrate the spirometer. Each subject produced at least three acceptable FVC curves based o ATS stadards. Permaet alphaumeric records of the acceptable curves were prited. Subjects were required to exhale for at least 6 secods or util a obvious plateau i the volume-time curve occurred. Measuremets of the two largest FVC ad FEVj could ot differ by % or ml. Pulmoary abormality i this study, based o VC ad FEV/FVC criteria, combied three groups: restricted, obstructed ad mixed; a fourth group was the ormal group. A 5cm X 5cm chest X-ray was take of each subject for use i diagosig peumocoiosis. Qualified persoel followed stadard operatioal procedures for each X-ray take. Oly X-rays of satisfactory quality were icluded i this study. Workig idepedetly, two thoracic specialists read ad assessed each X-ray. Diagoses were based o 98 Iteratioal Labor Orgaizatio (ELO) 4 classificatio stadards, i which peumocoiosis is deed as > /. X-ray film for each subject was preseted radomly to two physicias. I the evet that the two physicias made coflictig diagoses, a third physicia was used to make the fial decisio. Detailed records were kept of film quality, the profusio, shape ad size of small ad large opacities, ay pleural chages ad other additioal markigs for use i future studies. All radiological abormalities were of silicosis because workers were exposed to high levels of free silica: there were o other types of peumocoiosis. However, the curret study oly used iformatio regardig the diagosis of peumocoiosis. Statistical aalysis was performed usig SAS/PC software. 5 Next, chi-square tests compared differet exposure levels with persoal characteristics ad prevalece of respiratory symptoms. Aual chages i pulmoary fuctio (FVC ad FEVj) adjusted for age, height ad smokig were measured by liear regressio models. Lastly, factors ifluecig lug fuctio abormalities ad peumocoiosis were aalyzed usig the Matel-Haeszel test for tred ad logistic regressio models. RESULTS Persoal characteristics for workers i the four groups are show i Table. Age was the oly sigificat variable betwee the groups. The furace ad after-processig groups had the highest percetage of workers over 5 years of age:.8% ad %, respectively. Other variables icludig work duratio, smokig ad pack-year were ot sigificat. Furace ad mouldig workers had the highest percetage of smokers (both over 6%) ad the highest pack-year values (> 6), 5.7% ad.%, respectively. Respiratory symptoms for the four groups revealed sigificat differeces betwee smokers ad o-smokers (Table ). The prevalece of respiratory problems was higher for smokers. Amog smokers, the oly sigificat symptom was thoracic disorder (subject diagosed by a physicia as havig had a chest illess or chest tightess withi the past three years ad has bee abset from work for at least oe day as a result). Furace ad mouldig workers were highest overall,.5% ad 8.4%, respectively. Chroic phlegm ad chroic cough were the most commo symptoms foud i all groups, with the furace group the highest (.5% ad 7.5%, respectively). Brochitis was most commoly foud amog mouldig workers: 9.4% (smokers) ad 9.5% (o-smokers). Overall, the prevalece of COPD was the lowest amog all the disorders. Results from pulmoary fuctio tests for the four groups were compared (Table ). Overall, o-smokers had better test results tha smokers. Amog smokers, the furace workers had sigificatly poorest results for Table. Foudry worker's persoal characteristics based o job descriptio Variable Admiistrative (--= ) After processig = ) Mouldig < = 8) Furace ( = 6) p value <%) Age (yrs) <O >5 Work duratio (yrs) < >6 Smokig No Yes Ex-smoker Pack-years > (7.9) (8.6) (6.8) (6.8) (7.) (8.4) (7.) (7.6) (5.7) (58.) (6.) (6.) (.7) (9.7) (.5) (6.9) (6.8) (.) (.) (.9) (4.8) (7.9) (.4) (4.) (5.6) (5.) (4.) (.) (4.8) (4.7) (7.9) (6.4) (7.) (8.8) (6.) (5.7) (8.5) (9.5) (.8) (6.6) (5.5) (.) (5.5) (6.) (7.) (.5) (8.) (7.7) (.8) (7.9) (7.7) (9.7) (4.8) (4.4) (6.) (.4) (4.4) (4.8) (9.5) (.) Dowloaded from o July 8

4 5 Occup. Med. Vol. 49, 999 Table. Descriptio of job descriptio ad prevalece of respiratory symptoms based o smokig habit Variable Admiistrative After processig Mouldig Furace p value Smoker group Chroic cough Chroic phlegm Wheeze Dyspea Thoracic disorder Brochitis COPD* No-smoker group Chroic cough Chroic phlegm Wheeze Dyspea Thoracic disorder Brochitis COPD* 4 7 (6.7) (9.4) (9.9) (.8) (.) (4.) (.4) (5.) (.) (.) (.) 4 5 (6.7) (9.7) (.) (4.6) (4.6) (6.) (.5) (.9) (6.5) (4.4) (4.4) (4.4) (.) (.) (5.5) (6.8) (5.) (5.) (8.4) (9.4) (.9) (8.4) (6.8) (.) (.) (.) (9.5) (.) 4 5 (.5) (.) (.5) (.5) (4.8) (9.5) (9.5) (4.8) (4.8) (.) (4.8) Chroic obstructive pulmoary disease. Table. Compariso of pulmoary fuctio testig amog male foudry workers based o smokig habit Admiistrative ( = After processig (=) Mouldig ( = 8) Furace p value Smoker group FVC (ml) FEV, (ml) FVC/FEV, MMF (l/mi) PEFR (l/ml) FEF 5 (l/mi) FEF M (l/mi) FEF 78 (l/mi) No-smoker group FVC (ml) FEV, (ml) FVC/FEV, MMF (l/ml) PEFR (l/ml) FEF 5 (l/mi) FEF W (l/mi) FEF 75 (l/ml) 4.4 ±578.5' 7. ± ± ± ±. 5.5 ± ±.4.6 ± ± ± ± ±. 6.9 ±.9 5. ±.9. ±..58 ± ± ± ± ± ± ±.84.6 ± ± ± ± ± ± ± ±.4.8 ± ± ± ± ± ± ±.9.5 ±..66 ± ± ± ± ± ± ± ±.8.74 ± ± ± ± ± ± ± ± ± ± ± ± ± ± *.58 4.".97* " Meas ± SD; *p <.5; "p <.. PEFR (5.64 l/mi) ad FEF5 (5.4 l/mi). All other pulmoary fuctio idicators were o-sigificat. Amog o-smokers, furace ad mouldig workers had better test results tha the other workers, although the differeces were o-sigificat. A liear regressio model was set up to predict the average aual decrease i pulmoary fuctio for the four groups (see Table 4). All results (adjusted ad uadjusted) revealed that FVC ad FEVj values decreased directly correspodig to job descriptio. I compariso, furace ad mouldig workers exhibited the greatest decrease i FVC based o work duratio, ml/year ad -9.9 ml/year, respectively. These two groups also showed the greatest decrease i FEVj based o work duratio,.4 ml/year ad 6.65 ml/year, respectively. Table 4. Liear regressio model for aual chage of pulmoary fuctio based o work duratio; coefficiet parameters (ml/year) were adjusted accordig to age, height ad smokig Job descriptio Admiistrative After processig Mouldig Furace FVC (ml/year) Uadjusted Adjusted FEV, (ml/year) Uadjusted Adjusted FVC: forced vital capacity; FEV,: forced expiratory volume for oe secod. A logistic regressio model was set up to evaluate factors ifluecig pulmoary fuctio abormality (see Table 5). There were o sigificat differeces for pulmoary fuctio abormalities amog the four groups. Dowloaded from o July 8

5 H.-W. Kuoef a/.: Respiratory abormafitles of foudry workers 5 Table 5. Pulmoary abormality of risk factors usig multiple liear regressio Variable Normal Abormal Odds rath (OR) Adjusted OR (95% Cl) Job descriptio Admiistratio After processig Mouldig Furace Legth of exposure (yrs) < >6 Smokig (pack-years) >6 64 (57.) 64 (57.7) 8 (58.4) 7 (6.7) 5 (67.7) 5 (6.8) 57 (5.) 48 (4.7) 6 (6.4) 66 (66.7) 9 (58.) 9 (4.6) 48 (4.9) 47 (4.) 8 (4.6) 4 (9.) 5 (.) 8 (7.) 5 (46.7) 67 (58.) 76 (7.6) (.) 78 (4.7) 57 (59.4) *.9* * *.6"..9.9.* ( ) (.6-.55) (.46-.7) ( ) (.-.85) ( ) (.54-.5) ( ) (.-.65) *p <.5; **p <.. Table 6. Logistic regressio for factors ifluecig peumocoiosis i foudry male workers Variable Normal Peumocoiosis Odds ratio (OR) Adjusted OR (95% Cl) Job descriptio Admiistrative After processig Mouldig Furace Legth of exposure (yrs) < >6 Smokig (pack-years) >6 78 (97.5) 7 (88.6) (9.) 6 (8.7) (95.) 4 (9.) 74 (9.5) 78 (8.) 56 (94.6) 6 (96.9) (88.4) 5 (8.8) (.5) 9 (.4) (8.7) 7 (6.) 5 (4.7 (6.7) 6 7 (7.9) 9 (5.5) (.) 6 (.6) (7.) 5.*.7 7.6" " " 6.77* " " * (.5-.9) (.9-8.5) (.69-^7.7) ( ) (.4 ^t.96) (.48-.9) (.4-.9) (.9-5.7) (.-7.) *p <.5; "p <.. However, as work duratio icreased, so too did the risk of developig pulmoary fuctio abormalities. If work duratio exceeded 6 years, the risk icreased to.6, adjusted for other variables. Also, if the umber of packyears exceeded 6, the risk was., also adjusted for other variables. Thirty-eight of the 4 workers (8.8%) were diagosed with peumocoiosis. The highest prevalece was foud amog furace workers (6.%), followed by after-processig workers (.4%) ad mouldig workers (8.7%) (see Table 6). As compared with the admiistrative group, furace workers had 8.98 times the risk of developig peumocoiosis. After-processig ad mouldig workers were 6.77 ad 4. times at risk, respectively. As expected, risk of developig peumocoiosis icreased directly with work duratio ad job descriptio. Workers with over 6 years experiece were 4.7 times more likely to develop peumocoiosis tha workers with less tha years experiece. Smokig was also a sigificat factor i the developmet of peumocoiosis. Workers measurig betwee 8-5 pack-years had a.5 times higher risk of developig peumocoiosis, while workers over 6 pack-years had a.74 times higher risk. DISCUSSION Due to lax ati-smokig regulatios i foudries, may workers smoke while workig. The combiatio of exposure to airbore dust ad smokig ofte resulted i pulmoary fuctio abormalities. Aother risk factor is the poor quality or lack of persoal protective equipmet wor by the workers. Oly about % of mouldig ad furace groups icluded i this study wore a mask while workig. Masks typically wor were made of cloth ad Dowloaded from o July 8

6 54 Occup. Med. Vol. 49, 999 did little to filter out airbore dust particles. Oly about % reported wearig protective apros which may prevet workers from carryig harmful dust materials home o their clothes. Caudarella 7 ivestigated respiratory abormalities of workers from three cast-iro foudries. Caudarella cocluded that dust was ot the oly factor; smokig also cotributed to respiratory abormalities. There was a wide variatio withi the four groups i the curret study which meat that there was o sigificat differece betwee smokers ad o-smokers (except for FEVj/ FVC, FEFR ad FEF 5 i the smoker group.) However, overall, it ca bee see that the o-smokers performed better tha smokers sice smokig may reduce the lug's ability to remove dust by damagig the respiratory epithelium. Also, by ihalig more deeply durig smokig i the workplace, smokers may ihale more dust tha o-smokers. To esure accuracy of data with regard to respiratory symptoms, all symptoms were first reported by workers o a modified ATS questioaire the verified by physicia's examiatio. The highest levels of chroic cough (7.5%) ad chroic phlegm (.5%) were reported by the furace workers who smoked. These levels were sigificatly high because fie particles emitted from furaces vaporized ad became easily ihaled. Based o persoal sampler measuremets, the mass media aerodyamic diameter (MMAD) of dust particles was 5.5 uj. Kosztolayi 8 foud that the severity of tissue lesios caused by -5 u.m diameter particles was related to their electrophoretic mobility. Feg 9 ivestigated the health effects of occupatioal free silica exposure i iro foudries. Based o samples, the mea cocetratios of respirable dust ad free silica were.79 ±4.7 mg/m (ND -7.5) ad.5 ± 55. (ig/m (ND ), respectively. The highest GM cocetratios of both respirable dust ad free silica were foud i the sad recyclig area,. mg/m ad 7. u.g/m, respectively. The cocetratio of free silica i respirable dust was 4.5 ± 5.9 (ND -58). The curret study showed that respiratory abormalities were caused by exposure to airbore dust with a high proportio of free silica (7.5%) ad the small particle size. Sice tuberculosis prevetio programmes have bee successful implemeted i Taiwa, oly.84% of foudry workers have bee diagosed with TB, so it was ot a sigificat factor i the respiratory symptoms. Koskela 5 coducted a retrospective cohort study from (ad a follow-up to the ed of 987) o foudry workers, metal product workers ad electrical workers. Both the curret ad former foudry workers had higher rates of chroic brochitis tha the correspodig group of metal product ad electrical workers. The healthy worker effect was a sigificat factor amog workers doig physically heavy work ad is especially apparet i cross-sectioal studies. Because health screeig ad psychological tests are used to select persos fit for work, healthier persos are more easily selected for jobs tha less healthy persos. The healthy worker effect may have bee a factor i the curret study because workers who were exposed to high cocetratios of respirable dust did ot cosistetly exhibit poor results o the lug fuctio tests, or did they exhibit serious respiratory abormalities. A follow-up study or a compariso study of differet groups of workers could mitigate the healthy worker effect ad better establish the relatioship betwee exposure to harmful substaces ad health risks. However, as legth of exposure icreased so did the risks of peumocoiosis ad impairmet of the respiratory system. Myers' et al. 987 study of South Africa foudry workers reported the prevalece of peumocoiosis to be.%; for workers with more tha 5 years experiece it icreased to 8%. The study also showed that peumocoiosis was ot associated with higher prevalece rates of other respiratory abormalities. These results are cosistet with the curret study, although, Myers' study did ot report cocetratios of airbore dust. Myers reported that there was o relatioship betwee smokig ad peumocoiosis, but the curret study idicates that there is a idirect associatio, especially for heavy smokers. Results showed a egative correlatio betwee work duratio ad FVC ad FEVj, ad a reductio i lug fuctio with higher exposure levels. Although there are o available studies o exposure of foudry workers to free silica with which to compare the results of this study, it is iterestig to ote Seixas' study which examied pulmoary fuctio i ew miers exposed to coal mie dust. The major compoet of dust i coal mies ad foudries is free silica: they both have the same harmful effects o lug fuctio. The logitudial ad cross-sectioal aalyses of Myers' study idicated a rapid iitial loss of FVC ad FEV, i associatio with cumulative exposure, of the order of ml per mg/m -years. These results are cosistet with the curret study (the mouldig ad furace groups oly). I 985 Burrows et al. were able to geerate estimates of the declie i FEV, with time. They foud that the mea YEV^ deviated from the predicted value by as much as ml. Because cross-sectioal data were used i this study, the relatioship betwee cumulative exposure to dust ad decremets i pulmoary fuctio or icreased prevalece of symptoms of chroic brochitis were difficult to determie. If logitudial studies are to be performed, worker turover must be low ad exposure cocetratios must be measured regularly. Ufortuately, i Taiwa worker turover is relatively high ad records of exposure cocetratios are ot available, so cross-sectioal studies are commoly doe. Results from the curret study showed that respiratory symptoms ad aual chages i pulmoary fuctio are liked with job descriptio. Because of this clear relatioship, the govermet ca use these results as a referece for future moitorig of airbore dust cocetratios ad for justifyig regular pulmoary fuctio examiatios. The authors coclude that respiratory disorders ad lug fuctio impairmets (particularly for smokers) are associated with the foudry processes that produce large amouts of airbore dust ad with legth of exposure. Dowloaded from o July 8

7 H.-W. Kuo stel: Respiratory abormastjes of foudry workers 55 The authors suggest that istallatio of vetilatio systems ad provisio of persoal protective equipmet will help to improve workplace coditios ad reduce health risks to workers. REFERENCES. Palmer WG, Scott WD. Lug cacer i ferrous foudry workers: a review. Am IdHygAssocJ 98; 4: Low I, Mitchell C. Respiratory disease i foudry workers. BrJIdMtd 985; 4: -5.. Myers JE, Garisch D, Mayers HS, Corell JE. A respiratory epidemiological survey of workers i a small South Africa foudry. Am J Id Med 987; : Malmberg P, Hedestrom H, Sudblad B-M. Chages i lug fuctio of graite crushers exposed to moderately high silica cocetratios: a -year follow-up. Br J Id Med 99; 5: Koskela RS. Mortality, morbidity ad health selectio amog metal workers. Sca J VCbrk Eviro Health 997; (Suppl ): Os'guy G, Vaillacourt C, Begi R. Respiratory health of workers exposed to metal dusts ad foudry fumes i a copper refiery. Occup Eviro Med 995; 5: Johso A, Moira CY, MacLea LL, et al. Respiratory abormalities amog workers i a iro ad steel foudry. BrJ Id Med 985; 4: Mao IF, Li YC, Li CS. The health effect of foudries workers exposed to free silica. J Formosa MedAssoc 985; 84: Li YC. Study o the Hazard of Foudry Workers Exposed to Free Silica. Taiwa, ROC: The Execute Yua Departmet of Labor, 99.. Taia Hospital. Survey o the Lug Disorder i Foudry Worker. Taiwa, ROC: Taiwa Provice Departmet of Health, 99.. Kuo HW, Chag CC, Lai JS, Chug BC, Lee FC, Che CJ. Airbore dust cocetratios ad particle size distributio i foudry. Chia Medical College J 998; 7: Chag CC. Study o the peumocoiosis of foudry workers i cetral Taiwa. Istitute of Evirometal Health, Chia Medical College, Masters Thesis, America Thoracic Society. Stadardizatio of spirometry 987: update. Am Rev Respir Dis 987; 6: Iteratioal Labor Office. Guidelie for the Use of ILO, Iteratioal Classificatio of Radiographs of Peumocoiosis. Geeva, Switzerlad: ILO, SAS Istitute. SAS User's Guide: Statistic, Release 6.4 Editio. Cary, NC (USA): SAS Istitute Ic., Piacitelli GM,Whela EA, SieberWK, Gerwel B. Elevated lead cotamiatio i homes of costructio worker. Am IdHygAssocJ 997; 58: Caudarella R, Geari P, Tabaroi G, Cascella D, Raffi GB. Respiratory disease i foudry workers: A epidemiological survey i three foudries. Lavoro Umao 976; 8: Kosztoayi G, Kellermayer N, Jobst K. O the surface potetial of peumocoiotic dusts. Beitrag Pathologie Bader 97; 47: 4^4. 9. Feg CK. A study o the effect of occupatioal free silica exposure i iro foudry. Istitute of Public Health, Natioal Yag-Mig Medical College, Masters Thesis, Seixas NS, Robis TG, Attfield MD, Moulto LH. Logitudial ad cross-sectioal aalyses of exposure to coal mie dust ad pulmoary fuctio i ew miers. BrJ Id Med 99; 5: Burrows B, Lebowitz MD, Camilli AE, Kudso RJ. Logitudial chages i forced expiratory volume i oe secod i adults. Am Rev Respir Dis 985; : Dowloaded from o July 8

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