metallurgy is the scientific area that studies the manipulation of metals from extraction 
 to processing parts and components for general use . steel , brass , bronze , and various alloys 
 form marketable products in different ways , such as bars , tubes , plates , parts , and 
 components1 . the process of 
 transformation these materials involves the casting where the material is melted in furnaces 
 at temperatures up to 600c , releasing fumes and dust in high concentrations1 , 2 . usually this occurs in poorly ventilated closed areas , characterizing it as a job that puts 
 employees at high risk of occupational exposure via inhalation2,3,4 . lung diseases are the most common occupational health problems , with asthma occupational 
 and cancer occupational being the most prevalent respiratory diseases5 , 6 . the occupational 
 asthma in foundries workers occurs due to dust inhalation and can elicit specific reactions 
 such as bronchial inflammation , respiratory disorders , and irreversible airflow obstruction 
 and diseases such as chronic bronchitis , emphysema , pulmonary edema , and lung cancer5,6,7 . the presence of harmful agents to the 
 respiratory system in the workplace is a known fact , but the secondary effects of this 
 exposure and its side effects are underreported . this scenario remained until the 1990s due 
 to lack of educational programs available for workers8 . currently , data from the world health organization ( who ) estimate 
 that about 14% of occupational diseases are duly notified in latino america that requires 
 more attention these countries on monitoring and early diagnostics9 . physiotherapists as well as doctors , nurses , and safety professionals are responsible for 
 monitoring and control of the environment risk factors in the workplace . clinical signs and 
 early symptoms are important red flags that signify occupational lung diseases , followed by 
 differential diagnosis and use of other tools of assessment10 . the tools for assessment , prevention , and monitoring of 
 environmental and occupational respiratory diseases are lung function tests such as 
 spirometry and peak expiratory flow ( pef ) that , in addition to quantifying the disturbances , 
 monitor the progress of any respiratory disorder . the main advantages of the pef are cost , 
 effectiveness , and ease of use7,8,9 , 11,12,13,14 . occupational health 
 surveillance at work by a physiotherapist is a proposal of this study , which investigated 
 the influence of the exposure time in pulmonary function among metallurgy workers . a cross - sectional study was conducted with foundry workers within the metallurgical 
 industry ( metal casting process , shell molding line ; with shape - out tasks ) in sao paulo , 
 brazil . the study protocol was approved by the 
 local ethics committee ( protocol 0048.1.1186.000 - 10 ) . all workers who performed their duties 
 while exposed to high temperatures from ovens were selected to this study . workers were 
 excluded due to various reasons such as dismissal , sick leave , or refusal to participate . 
 all participants performed spirometry ( easyone tm , model 2001 ) according to the european 
 respiratory society / american thoracic society protocol ( 2005 ) at their workplace . the values 
 are expressed as a percentage of the predicted values obtained in brazilian subjects15 . the measurement of peak expiratory flow 
 was performed following three rapid exhalations by the patient ( mini wright standard with a 
 flow between 60 and 800 l / min ) . anthropometrics measure 
 ( height and weight ) of the participants were performed using the microlife brand , previously 
 calibrated stadiometer ( sany ) . to evaluate the activity level of the workers , the 
 international physical activity questionnaire ( ipaq ) short form was used . the questions are 
 related to the time spent engaging in physical activity in a typical week / habitual . people 
 were considered active if they had accumulated more than 150 minutes of moderate or vigorous 
 physical activity per week16 . then , a 
 routine physical examination and evaluation of previous medical history ; respiratory signs 
 and symptoms , according to a respiratory disease s questionnaire ; smoking history ; and 
 checklist were implemented . the foundry workers were 
 classified according to exposure time in high ( > 5  years ) and low exposure groups (  
 5  years ) . the data 
 were subjected to a descriptive statistical analysis , mean , standard deviation , and 95% 
 confidence interval . the one - way analysis of variance ( anova ) with bonferroni adjusted was 
 used to determine whether there are significant differences between groups ( <5% ) . the 
 statistical analysis was performed using the sigma stat software package , version 3.2 ( san 
 jose , eua ) . sixty - eight subjects were screened , and 63 met the eligibility criteria and were evaluated . the demographic and anthropometric characteristics of the participants are shown in table 1table 1.characteristics of foundry workers according to exposure time and control 
 grouphigh ( n=28 ) low ( n=35 ) cg ( n=46)mean ( sd)mean ( sd)mean ( sd)age ( yrs)37.7 ( 8.5)*30.9 ( 6.7)34.5 ( 9.8)weight ( kg)72.8 ( 7.4)74.2 ( 11.1)76.4 ( 17.1)height ( cm)1.68 ( 0.08)1.7 ( 0.07)1.71 ( 0.09)exposure time ( yrs)11.8 ( 5.7)**1.4 ( 1.3)-sd : standard deviation , * post hoc , bonferroni test  compared between high / low 
 exposure ( p<0.007 ) ; * * t - student test . sd : standard deviation , * post hoc , bonferroni test  compared between high / low 
 exposure ( p<0.007 ) ; * * t - student test the ipaq results showed that 54 ( 85.1% ) employees were active and 9 ( 14.9% ) were not active 
 enough . only 5 ( 7.9% ) employees reported previous respiratory diseases such as sinusitis , 
 pneumonia , and bronchitis in childhood . regarding tobacco , 9 ( 14.3% ) employees were smokers , 
 ranging from 3 to 30 pack / years with a mean of 14.3  14.0 . fifty - two ( 82.5% ) employees had 
 never smoked , and only two ( 3.2% ) were former smokers . regarding spirometry , a mean fvc of 
 4.57  0.94 l , accounting for 95  18% , were predicted ; fev1 of 3.73  0.74 l , 
 comprising 95.0  15.8% , were predicted in addition to a mean of 0.82  0.09 
 fev1/fvc ratio . there was no significance different between exposure time and control groups for pulmonary 
 function ( table 2table 2.pulmonary function of workers according to exposure time and control 
 grouphigh ( n=28 ) low ( n=35 ) cg ( n=46)mean ( sd)mean ( sd)mean ( sd)fvc ( l)4.4 ( 0.7)4.6 ( 1.0)4.4 ( 0.7)% pred95.3 ( 16.7)94.8 ( 18.8)89.7 ( 14.7)fev1 ( l ) 3.6 ( 0.5)3.8 ( 0.8)3.5 ( 0.7)% pred96.5 ( 14.0)93.8 ( 17.2)88.9 ( 14.0)fve1/fvc ( % ) 82.4 ( 7.0)81.7 ( 9.8)80.3 ( 10.1)peak flow ( l)505.0 ( 125.5)499.7 ( 118.5)505.4 ( 108.7)sd : standard deviation , fvc : forced vital capacity , fev1 : forced 
 expiratory volume in one second , pef : peak expiratory flow ) . fev1 : forced 
 expiratory volume in one second , pef : peak expiratory flow precautions against risks include adapting the sheds with exhaust ventilation ( equipment de 
 protectors collective ) and personal protective equipment ( ppe ) . the temperature was measured 
 by a thermometer installed in the foundry and is maintained at 3035c . from the results obtained in our study , we observe that irrespective of the time of 
 exposure in the foundry sector of a metallurgical industry , workers pulmonary function was 
 not altered . the participants analyzed were young adult males in agreement with data 
 obtained in the literature , where the professional profile of the base areas of the industry 
 was mostly male with a mean age of 35 years18 , 19 . around 85% of participants were 
 physically active ( ipaq results ) , which could have contributed to healthy habits and 
 positive spirometric results . because these are young individuals , the average of the time 
 on the job in these conditions is low  six years on average  a fact that was also seen in our 
 sample . no pulmonary signs and symptoms and previous history of respiratory diseases were reported 
 by workers , which validates the results of spirometry and peak expiratory flow being within 
 normal limits . lightfoot et al.20 
 attributes the occurrence of respiratory signs and symptoms to the type of metal inhaled and 
 the concentration and route of exposure to the metal , often missing the risk , such as 
 exposure to nickel . moreover , ahn et al.18 claims there is no parameter for analysis of exposure time . spirometry and peak expiratory flow were not significantly affected even when the results 
 were stratified according to length of employment , as annual decline in fev1 by 
 15% is considered clinically important by the american thoracic society ( ats)21 . syseth et al.22 followed workers at a smelter in norway over a period of 
 five years and noted the presence of airflow limitation in workers exposed to dust when 
 compared with those who were not exposed , but this limitation flow demonstrates the chronic 
 effects of exposure to risk factors . this fact is not repeated when it comes to respiratory 
 signs and symptoms of welders metal , exposure to the strongest fumes , and subsequent rapid 
 loss of lung function23 , 24 . kusaka et al.25 showed that an 
 interaction of hard metal exposure , smoking and respiratory symptoms decreased pulmonary 
 function for both men and women hard metal workers . among the currently 
 exposed men , those with symptoms ( like dyspnea or wheeze ) had significantly lower fvc , 
 fev1 , and pef than workers without respiratory symptoms . even among the men 
 without symptoms , the pulmonary function was significantly lowered by the interaction of 
 hard metal exposure and smoking . despite the longer exposure maintaining normal levels of lung function may be 
 associated with factors such as presence of younger individuals in the labor sector or low 
 tobacco consumption26 , but mainly with a 
 high percentage of the use of ppe by workers . donoghue et al.5 showed the 
 presence of occupational asthma in workers exposed to aluminum in the form of dust and 
 smoke . this was without the use by employees of personal protective equipment , in contrast 
 to our study when there was full adherence to the use of ppe and there were no changes in 
 spirometry or pef . on the other hand , workers exposed to iron considered that the risk is 
 lower when there is an association with iron and other metals , such as silica27 . we observed that both the enterprise and 
 the workers were concerned about compliance and correct use of ppe . wang et al.28 observed significant reduction in 
 fev1 in individuals exposed to a series of secondary factors to the 
 occupational environment , where the use of ppe was positively correlated with no changes in 
 fev1 . in contrast , de capitani et al.29 found that the use of ppe can not be taken as cancellation of the 
 risk factors . studies about smoke 
 show a direct correlation between smoking and socioeconomic class , i.e. , a higher prevalence 
 among men with lower education and with lower salaries30 . in the present study , although they were a class of individuals 
 with less privileged socioeconomic and cultural status , this was not the case , only 8 
 ( 5.04% ) were smokers . according to an interview conducted during clinical examination , few observations with 
 regard to prevention and early diagnosis of occupational diseases , as previously assessed in 
 the industry , were not conducted . specific tests such as spirometry and peak expiratory flow 
 were not conducted unless employees reported lung symptoms . this is part of a series of 
 modifications in the care and precautions the company gives to employees in order to 
 evaluate them better , but this may have been a limitation of this study since we did not 
 have previous examinations or chest radiographs that could reveal early pulmonary changes 
 that are not visible in the pulmonary function test . we can not confirm with certainty that 
 the results would be caused by several factors such as age , length of service , the type of 
 metal to which employees were exposed , or ppe use . we reiterate the need to carry out 
 follow - up studies over time to assess possible changes in lung function of exposed 
 workers .
[ purpose ] this cross - sectional study aimed to compare foundry workers of the 
 metallurgical industry with high and low exposure time and with a control group . 
 [ subject 
 and methods ] the workers were evaluated for pulmonary function and peak expiratory flow 
 ( pef ) , respiratory symptoms , smoking habits , and physical activity level . 
 descriptive 
 statistical analysis and anova one - way test were used . 
 [ results ] the mean age was 33.9  
 8.25  years ( 1859 ) , pulmonary function : fvc : 95  18% of predicted , fev1 : 95.0 
  15.8% of predicted , fev1/fvc ratio of 0.82  0.09 , and pef = 499.7  118.5 
 l / min . 
 overall , 85.1% of workers were classified that physically active , 7.93% of workers 
 reported respiratory symptoms , and 14.28% reported being smokers . 
 there was no 
 statistically significant difference between groups for the variables of lung function . 
 [ conclusion ] the pulmonary function is preserved in foundry workers independently of 
 exposure time .