Document rp4yL7NyKRQdNrBpydb3vBwbG

REPORT ;;c. TA/SZ/k UDC 612.2 : 67?.7^3 AN EPIOEMICLCGICAL STUDY OF THE LUNG FUNCTION OF -CRXERS AT A FACTCRT MANUFACTURING POLYVINY LCTILQ RIDS by HE Lloyd S Gauld L Copland CA Soutar JANUARY 1932 UCC 066975 INSTITUTE OF OCCUPATIONAL MEDICINE AN EPIDEMIOLOGICAL STUDY OF TEE LUNG FUNCTION OF WORKERS AT A FACTORY MANUFACTURING POLYVINYLCHLORIDE *7 NH Lloyd, S Gauld, L Copland, CA Soutar Madieal Branch Instituta of Occupational Madieina, Roxburgh Placa, EDINBURGH EH8 9SU. (Tal. 031 667 5131) JANUARY 1982 UCC 066976 (ii) CONTENTS Page No. ABSTRACT (iv) 1. INTRODUCTION ........................................................... 1.1 Respiratory effects of VCM sad PVC . 1.1.1 Animal studies .................................. 1.1.2 Clinical studies . . 1.1.3 Epidemiological studies .. 1.2 The present study ........................................... 1.2.1 The PVC factory . . . . 1.2.2 Tne foundry . . . . . 2. METHODS....................................................................................... 2.1 Selection of the surrey population ... 2.2 The medieal surrey ....... 2.3 Methods of analysis ....... 2.3.1 Classification of smoking histories . 2.3*2 Analysis of data from total surrey population ....... 2*3*3 Selection of cases and controls . . 2.3. ^ Case-control study ............................................ 1 1 2 2 3 3 5 6 6 6 7 7 7 8 8 3. RESULTS .............................................................................................. 3*1 Description of total surrey population . . 3.2 Analysis of lung function data from total Ourrey population 3.2.1 Calculation of predicted values and standardised residuals ... 3*2.2 Distribution of standardised residual values of T-co and for total survey population ................................... . 3.2.3 Selection of eases and controls . . 3*3 General features of eases, controls and the total survey population ...... 3.3*1 Age, height and weight .... 3.3*2 Employment status and smoking habit . 3*3*3 Lung function *...... 10 10 10 10 10 10 11 11 11 ii ucc 06697? (iii) Page No. 3^ Clinical description of Ttco cases and FEVt cases 3*5 Case-control study ........ 3.5.1 Occupational histories of cases and controls ........ 3*5*2 Smoking habits of eases and controls . . 12 12 12 14 4. DISCUSSION........................................................................................... 16 5. CONCLUSIONS AND RECOMMENDATIONS....................................... 19 ACKNOWLEDGEMENTS REFERENCES TABLES FIGURES APPENDICES ucc 066978 Report No. TM/82/4 (iv) INSTITUTE OF CCCUPATICNAI MEDICINE AN EPIDEMIOLOGICAL STUDY CF THE LUNG FUNCTION OF WORKERS AT A FACTORY MANUFACTURING PGLTVI'TCLCKLCRIDE by MB Lloyd, 5 Gauld, L Copland, CA Soutar ABSTRACT V have conducted an epidemiological study to investigate a reoort that some men working in a factory manufacturing polyvinylchloride (PVC) had abnormally low values of one lung function test, namely the sirgle breath transfer factor for carbon monoxide (Tuco). We studied 265 present and past employees of the PVC factory, and 219 men from the workforce of a nearby foundry. The foundrymen were included to increase the number of men with little or no e-posure to possible rusriratory hazards at the PVC factory. Each man's Tlco was measured, and smoking history and detailed occupational history obtained. More detailed lung function teats were carried out on the PVC workers only (forced expiratory flow-volume curves). The study consisted of two perts; aessurement of the Tuco of current snd past employees at the factory and current foundry employees and examination of the distribution of residuals after allowing for age, height, weight and smoking hsbit, to search for evidence of an excess of men with low slues of Tuco; and s case-control study* In this, men with the lowest Tuco after allowing for age, height, weight and smoking habit were selected as cases, snd their occupat ional history compared with that of two groups of controls; ons group selected from those with near average gas transfer alues, and another group from those with the highest values. The Tuco results among this combined population conformed to a Normal distribution after allowing for age, height, weight and smoking habit, and did not suggest that s substantial number of men had clinically important impairment of their Tuco. The 31 men selected as 'esses* included 15 men whose Tuco was abnormally low (less thsn 7<& of published predicted values), of whom JhhU*"were PVC workers and were foundrymen. Among the 19 esses w rkir.g at th PVC factory the pattern of lung function abnormality suggested that the low Tuco was (v) accompanied by evidence of airflow obstruction in 11 men, suggesting the presence of emphysema, but was an isolated functional abnormality in the other eight, possibly suggesting the presence of pulmonary fibrosis or abnormalities of lung perfusion. PVC workers ware slightly over-represented among the eases, although this difference could easily have arisen by chance. Men who had worked on jobs at the PVC factory which were close to the pressure vessels where exposure to vinyl chloride monomer was most likely to have occurred in the past, were also slightly over-represented among the eases, and this difference approsched statistical significance at conventional levels. There was, furthermore, a statistically significant association between low Tuoo and a history of having worked at the PVC factory before 1975- This date is important because it was at this time that exposure of the workforce to vinyl chloride monomer was drastically reduced, in the light of information about some of the potential hazards of this gas. The cases included slightly more smokers them the controls, and those cases who smoked, smoked slightly more heavily than controls. The relative importance of these end other factors in causing the lung functional abnormalities is not clear, but these findings give some support to the hypothesis thst work in the PVC factory before 1975 involved exposure to a substance that caused impairment of lung function In a small number of men. There was no evidence of s relationship between low Tteo values and current working conditions at ths PVC factory or with past or present conditions st ths foundry. The results suggest that more detailed studies of ths relation ships with vinyl chloride monomer, polyvinylchloride, smoking habit and ether causative factors would be desirable, together with a clinical aasessment of the lung damage in selected men. UCC 066980 1. INTRODUCTION The health of workers employed in the manufacture of polyvinylchloride (PVC) has been a cause of coco err. during recent years. Some adverse effects of exposure to vinyl chloride monomer ('/CM) are well recognized, but lung disease in man has net been shewn tc be related to exposure to YCM. Exposure to airborne PVC dust, however, has been shown to cause slight, impairment of lung function and slight chest radiographic abnormalities. Vinvl chloride is the basic raw material used in the production of PVC. Although the manufacturing process was first developed in 1923 in the USA it wss not until 50 years later that evidence of the texie effects of vinyl chloride exposure began to accumulate. CCPDflP. (1f*3)- 'as the first to describe aero-osteolysis in reactor cleaners in Belgium and in the following year SUCTC (1967) described Raynaud's phenomenon among workers in a PVC factory. Changes in the skin and internal ergar.s were subsequently recognised and in 197** the terra 'vinyl chloride disease' was used to describe the 3yrdreae which has cany features in common with scleroderma (VELTKAN t al., 1975). The hepatic effects of exoosuro to VCM have aroused the most interest and include ncn-callgnant changes. It was the discovery of the association between vinyl chloride exposure and angiosarcoma of the liver (CREECH and JOHNSON, 197*0 which caused the greatest concern end affirmed the need for stricter control of exposure levels. In 1975 regulations were Introduced which established a ceiling exposure value of 50 parts per aill'ics (ppm) and an eight-hour time weignted average (TVA) of 10 ppm. In 1930 the permitted maximum exposure was reduced to an annual averse# of 5 ppm. 1.1 Resniratarv effects of VCM and PVC The work described in this report was eoafined to a study of the lung function of workers in m factory producing PVC where men were exposed potentially to VCM, PVC and the other compounds used in the manufacturing process. Previous studies involving the use of animals, observation on patients and epidemiological surveys, have provided information or. th potential respiratory effects of these compounds. UCC 066981 2. 1.1.1 Animal studies The toxicity of both VC and PVC baa bees investigated in animal experiment*. P30DAN et al. (1975) exposed guinea pigs to ICES vinyl chloride concentration for two hours daily for periods of up to three months. At autopsy the lungs of all exposed animals showed the presence of fibrosis vhich was most severs in the animals which had had the longest exposure time. ACASWAL et al. (1978) studied the effect of intratracheel injections of PVC dust in rats and found that inflammatory changes were induced in the terminal and respiratory alveoli and that granulomatous lesions associated with multimxcleated giant cells developed. Similar giant cells end histiocytes were Identified in the alveoli of the lungs of small mammals which were kept is the bagging area of a PVC factory (FEONGIA at al.. 197*0. 1.1.2 Clinical studies There have been isolated case reports of pulmonary disease in workers employed in factories manufacturing PVC. AEKAITO et al. (1973) studied a 53-year-old man who had worked for 25 years in the bagging plant of a PVC factory. Eis chest X-ray showed micronedular shadowing and lung biopsy revealed large numbers of macrophages containing partlculata material and moderate diffuse fibrosis and a few alveolar granulomata. Eowever, his symptoms were few end apart from a alight reduction in. vital capacity, bis lung function tests including his transfer factor for carbon monoxide were normal. His disease was probably related to PVC dust rather than VCH. DA2XE (1976) investigated 14 men who oad been employed in a PVC manufacturing plant exposed to VCH and all of whoa complained of breathlessness. He found that thoir ehast radiographs were normal. In six of these aen transfer factor for carbon monoxide is reported as being impaired but no measurements or details of other lung function tests are given. Lung biopsy from one of tbs sen showed focal alveolar wall thickening and macrophages present in alveolar spaces. LAHGS et al. (1973) described some esses or VC workers with impairment of transfer factor for carbon monoxide, but the relationship with occupation was not- dear. ucc 066982 1.1.3 3 Epidemiological studies Studies of pulmonary function of workers employed in PVC manufacturing plants have produced conflicting results, and it has not always been possible to separate the effects of FVC dust from potential effects of VCH. A high prevalence of abnormal lung function, mainly obstructive in type, was found by MILLER ^t al. (1975) and LIL1S et al. (1975; 1976) among workers in two PVC manufacturing plants in the United States of America but smoking was not taken into account in the analysis. Smoking effects were allowed for in the study by GAMBLE et al. (1976) which compared the lung function of workers in a PVC plant with that of rubber workers and chemical workers exposed to VCM: no significant differences were found in the lung function of these three groups but no measured personal exposures were available. VERTKIN et al. (1970) studied 96 PVC workers in the USSR and found a high prevalence of chest radiograph abnormalities but the majority of the workers had normal lung function teats. CHIVER3 ct al. (1930) similarly found no apparent Impairment of lung function among 509 employees in a PVC factory of whom 104 were exposed to PVC dust only, 112 to non-ehlorinsted solvents only and the remaining 293 ware exposed to a mixt'ire of both. Ho difference between the three groups was identified and the observed impairment of lung function is some men was related entirely to the effects of smoking. However, measured personal exposures were not available for these men. A study of 8lS men currently and previously employed at a PVC manufacturing plant (SOUTAS et al., 1980) in which estimates of personal exposure to FVC dsst were based ea detailed occupational histories and current measurements of dust levels in the factory showed a statistically significant reduction in tests of lung function among men with the highest PVC dust exposure, and some of these men had small rounded opacities on their chest radiographs. The non with those radiological changes had significantly lower mean lung function test values than men whose films were considered to bo normal. Ho relationship was found between exposure to PVC dust and impaired transfer factor for carbon monoxide. 1.2 The present study The present study was requested by Vinatex Ltd., and was carried out with the full agreement of management and werkforco, and arose from tb ir concern about some employees whose lung function, particularly the ucc 066983 4. transfer factor for carbon monoxide, appeared to be abnormal. The transfer factor for carbon monoxide measures the ability of the lung to exchange gases between the inspired air and the blood. The study was designed to describe the distributions of various measures of lung function, including the transfer factor, in current and former employees at the FVC factory and to identify men with low lung function values. These men would be regarded as 'cases' and would be compared with two groups of controls, in order to examine possible associations between abnormally low lung function values and personal, occunational and environmental factors. The total survey population included the workforce of two factories; one was the ?VC factory of interest and the other was a large iron foundry situated a few hundred yards away. 1.2.1 The PVC factory The plant had been in operation since 1969 and for most of that time had produced suspension polymer. For a period of three years (1971 - 1974) emulsion polymer, which has a smaller particle size than suspension polymer, had been manufactured in one of the twe reactor buildings. During the manufacturing process vinyl chloride is pumped from the tank farm storage area via another storage tank to two reactor buildings. Under conditions of increased temperature and pressure and in the presence of other substances acting as catalysts and surfactants, polymerization of VCM takes place. The resulting FVC is piped as a slurry to blending tanks and is then dried by centrifuging and rotary drying. The dried polymer is sifted snd either removed to storage silos or bagged snd stored in the warehouse before being dispatched. The manufacturing process is operated in batches throughout the 24 hours and the workforce is divided into four shifts. In the reactor and dryer buildings men usually start as 'B' operators and esn then proceed to be 'A' operators and sometimes 'Lead* operators. , Available data suggest that prior to 197? levels cf VCM in the factory were considerably higher than the current low levels. During the period 1969 - 1975 eu working in the reactor buildings, and particularly those involved, in the manual cleaning of raactors. are likely to have been exposed to th highest 1 vela of VCM. 1 ucc 066984 1*2.2 The foundry 5 The foundry was situated near the FVC factory in the same industrial alley and manufactured moulded steel products* The manufacturing process involved the production of molten steel which was cast into appropriate moulds to which various finishing techniques were applied. UCC 066985 6 2. METHODS 2.1 Selection of the survey population All 177 men currently employed at the PVC factory were invited to take part* The names of another 263 men who had worked at the plant since it started production in 1969 were identified from factory records and attempts were made to trace and invite all these men using information supplied by the management, union representatives and local records. At the foundry the study was confined to 285 men selected randomly from the 1,385 current mala employees. 2.2 The medical survey The factories were visited by the medical survey team and men were seen by appointment. Details of each man's smoking history were recorded by a trained elerk using a questionnaire which was a modified version of the smoking section of the Medical He search Council Questionnaire of Respiratory Symptoms (MHS, 1976) (see Appendix 1). A full occupational history was recorded for each man by a trained clerk who had previously visited both factories and was familiar with their layout and the manufacturing processes. Details of sll jobs which a man had done since leaving school were recorded and the time spent in each of them noted. All PVC factory employees had measurements of forced expiratory volume in one second (7EVt), forced vital capacity (FVC) and gas transfer factor for carbon monoxide (Tvco). For foundry workers, approval was ootained for measurement only of Tuco. Measurements of FZVj and FVC were made using an electronic dry rolling-seal spirometer (Ohio 800). After a practice expiration, three forced expirations which ware considered to he technically satisfactory from a maximum of six were recorded. The maximum values of fEVj and FVC, not necessarily in the same breath, were used for the analysis, and the ratio of FEVj to FVC was derived from thes figures. ucc 066986 7 Single breath gas transfer factor for carbon nonoxide (Tuco) was measured by the breathholding method of MEADE et al. (1965) based on the modified Krogh technique. An automated spironeter/gas sampling system (Transfer Test B, P.K. Morgan Ltd., Chatham, Kent) was used and duplicate estimations were made for each man at least 10 minutes apart. Technically unsatisfactory tests were rejected and repeated (i.e. if the inspired volumes of the two tests differed by more than 1G, if the spirograms of the manoeuvres were of different shape or if the rates of inspiration and expiration were too slow). The mean of the results of the two satisfactory tests was used in the analysis. Each man was weighed fully clothed and his standing height measured. 2.3 Methods of analysis The data were studied initially by summary descriptive statistics and multiple linear regression analyses of lung function talcing into account age, height, weight and smoking habit. Subsequent examination of the standardised residuals* was carried out and on the basis of this cases and controls were selected. 2.3.1 Classification of smoking histories Men were assigned to one of three smoking categories; lifelong nonsmoker, current smoker and ex-amokar. Ho distinction was made is the analysis between type of smoking and the two 'smoker* groups included smokers ef manufactured cigarettes, hand-rolled cigarettes, pipes and cigars, since the majority of mss smoked manufactured cigarettes. 2.3*2 Analysis of data from total survey population The distributions of lung function and various explanatory variables * A standardised residual, SB, is the difference between an observed lung function value and its predicted value from multiple linear regression analysis, divided by the estimated standard deviation of the unexplained variation from thia model. i SR m (observed value - value predicted from fitted equation) (estimated standard deviation of the prediction) UCC 066987 8 were examined for systematic patterns amongst current and former employees of the PVC factory and current employees at the foundry. This was further explored for Tueo and FEV1 by multiple linear regression analysis taking account of age, height, weight and smoking. The relationship between a man's observed and predicted values was expressed as a standardised residual (SR). Thus men whose observed values were close to the predicted values would have SR values clustered sround zero and correspondingly men with impaired lung function would have the largest negative SR values. The distribution of SR values was examined to aee if there was evidence of an unexpectedly large number of men with impaired lung function and if so, to examine if either PVC factory or foundry employe's were over represented amongst these men. 2.3.3 Seisetion of cases and controls For each lung function variable those men with the largest negative SR values were ehesen as cases. Two groups of controls were selected rendcmly, firstly from those men whose SRa were clustered sround zero and secondly from those with the largest positive SRs. 2.3.4 Case-control study Casas were Initially compared with the rest of the survey population in order to identify systematic differences saongst related factors, e.g. age, smoking habit, employment status* 'The occupational and smoking histories of esses and controls were studied for systematic differences. Fisher's exact test, chi-squared tost for 2x2 contingency tables and chi-squared teat for linear trend were used where appropriate. Classification of smoking and employment histories Smoking histories were classified as they were for the total population (see Section 2.3.1). Additional information about the number of cigarettes smoked and age of starting smoking was analysed in the esseeontrol study. Bread occupational categories were defined for both PVC UCC 066988 9 factory and the foundry (Tables 1 and 2) and the total number of years spent by all cases and controls in each occupational category was calculated. Additional information was available for PVC employees in relation to exposure to emulsion polymer and employment in the factory prior to 1??5. From the- full occupational history, the number of years in 'noxious' industries was recorded. 'Noxious' industries were classified into four groups; the coal and chemical industries have certain well recognized hazards, while the lung function of men in the steel industry has been reported to be lower than men in non-dusty employment (HIGGINS, 1970); the fourth, designated 'other', included industries iu which hazards could possibly arise although they would be less likely than those of the otner groups (see Appendix 2 for a list of 'other noxious' jobs). Employment of sen in the manufacturing of PVC other than at the PVC factory was also noted. ucc 066989 10, 3. RESULTS 3.1 Description of total survey population A total of 488 men waa seen consisting of 165 current FVC factory employees (95S of those who were asked to participate), 102 PVC factory leavers (39& of those who were invited) and 221 foundry employees (78$ of those invited). Three men (one from each employment category) did not complete the Tlco measurement and one foundryraan did not have height and weight values recorded; the analysis was based on the remaining 484 men. FEVj and FVC measure ments were not obtained from three FVC factory leavers and were not carried out on the 221 foundrymen and the analysis was based therefore os 264 men. 3-2 Analysis cf lung function data from total survey population 3.2.1 Calculation of predicted values and standardised residuals The effects of age, height, weight and smoking habit on the Tlco and FEV1 were studied in this population by multiple linear regression. The development of the regression model used is described in Appendix 3* Standardised residuals (SR) for Taco and FEV1 were calculated for each man from the final regression model. Thus a man's standardised residual Tlco represents the amount by which his Tuco value differs from that predicted by his age, height, weight and smoking habit after standard isation. 3-2.2 .Distribution of standardised residual values of Tuco and fSV, for total survey population After allowing for the above factors, the standardised residual values of TLco for the total survey population showed a symmetrical distribution, with no greater number of men in the negative tail of th distribution than would he expected to have occurred by ebaoce. This 1 indicated that there was no evidence that a substantial number of men | had suffered a clinically important reduction of their Tuco. However, for the FEV^ SS distribution there were slightly sore extreme negative values than extreme positive values (Figures 1 and 2). 3*2.3 Selection of casts and controls UCC It warn decided that about 30 cases would form a study group of 066990 appropriate size. The threshold S3 value for Tuce below which there was approximat ly this number of men, was - 1.5. giving 31 sen. A 11 control group of 31 men was selected randomly from those men with SB values between - 0.25 and + 0.75 inclusive (Tuco 'average' controls). A second control group of 31 'extra-healthy* men was selected randomly from those with S3 values in excess of 0.75 (Tlco 'healthiest' controls). Similarly 30 men with an FEV* SB value of less than - 1.1 were selected as FSVl cases and two control groups, each of 30 men, were selected randomly from those with an SB value between - 0.25 and + 0.75 inclusive (FEVj 'average' controls) and from those with an SR value in excess of * 0.75 (FEV* 'healthiest' controls). 3.3 General features of cases, controls and the total survy population 3.3.1 A?e, height and weight The mean age, height and weight of Tuco cases snd controls, FEVj eases and controls snd the total population are given in Tables } and 4. TLco cases and controls were of similar age but cases tended to be taller than the control groups. Although the mean ages of T-co eases and control w* groups were similar, study of the age distributions (Table 5) showed *n |: excess of current PVC factory employees in the 45 . 54 age group when compared with both groups of controls and the rest of the population. FEVt cases were slightly older and taller than the controls and the rest of the population but thera was no differenes in the age distribution between employment groups or easss and controls. 3.3*2 Employment status snd smoking habit The employment status of cases, controls snd the total population is shown in Tables 6 and 7* PVC factory employees were slightly over represented amongst Ttco esses but this eould easily have occurred by ehance. # 12 Observed Tuco and FV1 values were expressed as a percentage of values predicted on the basis of Cotes' s regression model (COTSS, 1979) and the distribution of these values for eases, controls and the total population are shewn in Tables 8 and 9. 3.4 Clinical description of Tuco cases and F5V, cases Fifteen men (nine F7C workers and six foundrynen) of the 31 Tuco cases had Tuco values below 7C% of their predicted values and four of these were below 6($i (Table 8). Nineteen of the 31 cases were from the PVC factory and of those, four mer. had FZV1 values of less than 806 of their predicted value and low FEV1/FVC ratios indicating airflow obstruction. The remaining 15 men had FEVl values within the normal range although further examination of their lung function data (forced expiratory flow-volune loops) suggested that seven of these might 'neve mild airflow obstruction. Details of the 10 PVC workers with the lowest Tuco standardised residual values are given in Table 10. Of the 30 ~H'/1 cases, 15 had observed 7EV1 values below 8c& of their orcdicted valuer and 10 of these were less than 70S (Table 9)* The majority (10) of the 13 men with reduced FEV* had FEVj/FVC ratios below 7C& suggesting airflow obstruction. Seven of the Fa*^ cases were also selected as Tuco eases.. 3.5 Case-control study The occupational histories and smoking1 habits of esses and controls were compared in order to explore the observed differences in their lung function. ?*5.1 Occupational histories of cases and controls Analyses of the current employment status of eases and controls showed that PVC factory workers were slightly over-represented amongst the Tuco eases (Table 5), though this difference could easily have erisen by chance. The majority of PVC workers had worked in more than one type of job and is more than one broad occupational category during their employment with the company. Analysis of the mean duration of employment in each broad category failed to shew any differences between T<o esses and their UCC 066992 13. controls (Table 11), though more cases than controls had worked in jobs in category 1, those occupations close to the pressure vessels where exposures to VCM were mostly likely to ha\e occurred in the past. This difference could easily have occurred by chance, if PVC workers alone are considered but if the foundrymen are included, 11 of 31 cases (35&) had worked in category 1 jobs in the PVC factory, whereas only 10 of 62 controls (169) had done the same. The difference is significant at the 7% level. These occupational differences were not apparent for the FEV, cases and controls (Table 13). * There was also movement between jobs at the foundry but there were no differences in the pattern of employment cf cases and controls (Table 12). Pre-1975 employment Following the recognition of the hazards of VCM exposure in 1973, levels of VCM in the factory were progressively reduced during 197^ and by January 1975 the exposure levels were low. The numbers of cases and controls who had heen employed at the PVC factory before 1st January 1975 were compared. Seventeen of the 19 FVC worker Twco cases had been employed before 1975 compared with five of the 15 'healthiest' controls and 11 of the 13 average controls (Table I1*). Using a Xs test for trend, there waa strong evidence to suggest s significant increase in the proportion of men working before 1975 ever 'healthiest' controls, 'average* controls snd esses. Looking st comparisons between groups only the difference between cases and 'healthiest' controls was significant. Analysis of the duration of employment of men within different age groups showed that pre-1975 working was seen, in younger as well as in oldsr men (Tables 15, 16, 17). No differences were seen in the number of men employed before 1975 between PVC factory FEVX cases and controls (Table 18). A similar analysis of foundry Tueo eases failed to show any relationship with pre-1975 employment (Table 19). In conclusion there is evidence to suggest that employment at the PVC factory before 1975 was associated with impairment of TUeo. UCC 066993 14 Exposure to emulsion polymer The employment of cases and controls in the manufacturing of emulsion polymer was studied and compared. No man had been exclusively involved in the production of emulsion polymer so men were divided into three groups; those who had worked with suspension polymer only, those who had worked with both suspension and emulsion, and thcso who had not been exposed to either. Similar proportions of Tlco cases and controls (Table 20) and FEVj eases and controls (Table 21) are represented in each S5Sof these three groups. There is no evidence that exposure to emulsion fc/Bpolymer adversely affected the lung function of those who worked with Sit. Frevious employment in other industries There was so evidence that the observed differences between cases and controls could be explained on the basis of previous employment in industries other than the PVC factory or the foundry. No differences were found either in the numbers of cases and controls or in the mean numbers of years spent by them working in other industries which might be considered noxious tl.e. coal, steel, chemicals and 'others') (Tables 22, 23, 24). No men had been employed in the manufacturing of PVC outside this PVC factory. 35*2 Smoking habits of cases and controls A higher proportion of Two eases (6j9f) were current cigarette smokers than were either group of controls (4&) or tots! survey population (49$) (Table 2$). This difference was not seen between the FE^ cases and controls but there were more ex-smokers among the FEVX cases than there were eaong the controls (Table 26). The aaoklng histories were examined in greater detail by analysing the number of cigarettes which current cigarette snokers smoked daily both on weekdays and during the weekend, the number smoked by each man during the maximum smoking period of his life and the age at which each man started smoking. There was no significant difference in the number of cigarettes smoked on weekdays between both groups of cases and the'healthiest' controls (see Figures 3 and 4), and similar results wer found f r 'average' controls. UCC 066994 15 Analysis of weekend smoking showed that more Tuco cases smoked 25 or fmore cigarettes per day than did the Tuco healthiest controls (figure 5). No such difference was found to exist with average controls. Comparing the weekend smoking habits of PVC factory and foundry Tuco cases, it was found that a larger proportion of foundrymen smoked mere than 25 cigarettes per day (Figure 5). For the FZVX men, more cases than average controls smoked 25 or more cigarettes per day at weekends. This difference was not seen between eases and healthiest controls. Consideration of the number of cigarettes smoked during a man's maximum smoking period showed that of the men at the PVC factory, five of the 13 Tuco cases, compared with rone of the six Tuco'healthiest' controls, had smoked a maximum of 25 or more cigarettes per day (Figure 6). out this difference in proportions could easily have arisen by chance. The age at which men started smoking was also examined. There were significant differences between cases and controls. Of the 20 Tuco cases who were current smokers, eignt had started smoking by the age of 15 compared with one out of the I** 'healthiest' controls and 16 had started by the ace of 16 compared with five out of the It 'healthiest' controls (Firure ?a), while the figures for average controls were that six out of 15 had started smoking b7 the age of 16 (Figure ?b). Of the 13 FEVj eases who were current smokers, seven hsd started smoking by the sge of 16 compared with two of the 11 'healthiest' controls (Figure a). These differences were not seen between esses and 'average* controls (Figure 9b In conclusion Tuco esses and 'healthiest* controls and FSV; eases and 'average' controls differed in the number of men smoking 25 or more cigarettes per day at weekends. A similar difference was found between Tuco cases at the PVC factory and the foundry. In general, eases started smoking at a younger age than controls. ucc 066995 16 4. DISCUSSION The present study had two aims. First, to describe the lung function, particularly the Tlco, of current and past employees of a factory manufacturing PVC, and seek evidence of a possible excess of men whose Tlco was abnormally low. Second, to examine the relationship between Tlco and occupation and other personal and environmental factors by a ease-control study, in which the eases were men with lowest gas transfer factor after allowing for age, height, weight and smoking habit. Men from a nearby foundry were included in the study in order to increase the number of men with low or no exposure to possible respiratory hazards at the PVC factory, but who were exposed to similar environmental conditions outside their workplace. In all 265 men from the PVC factory and 219 men from the foundry were included in the Two analysis. The Tlco residuals among this combined population conformed approximately to a Normal distribution after allowing for age, height, weight and smoking thabit, and did not suggest an undue excess of extremely low values. This [indicated that it was unlikely that a substantial number of men in the whole population were suffering from a clinically important reduction of Ihe Tlco. In the case-control study the 31 men with the lowest Tlco after allowing for age, height, weight and smoking habit were selected as 'cases'* This does not imply that all 31 wars suffering from lung disease, but smong them were 15 men whose Tlco was less than 7GK of the value predicted by published normal values, a lovel which would generally be regarded as abnormally low. Among the 19 cases at the PVC factory the pattern of lung function accompanying the low Tlco was that of dsfinite airflow obstruction in four men* and possible airflow obstruction in another seven men, suggesting tbs presence of emphysema. The remaining eight men did not have evidence of airflow obstruction or reduction of their lung capacity (*ltnl capacity). This pattern is unusual in clinical practice, and may possibly reflect pulmonary fibrosis or disturbances of the blood flow in the lungs. The degree of reduction of transfer factor of earb n monoxide and associated airflow obstruction might hare been sufficient t esuae breathlessness on exertion in some of these sen. ucc 066996 17 The possible contribution of occupation in causing these lung function abnormalities was examined by comparing the occupational histories of the cases with those of controls. Two groups of controls were selected; one group from men with values of gas transfer near the mean for this population; the other group from those with values towards the high end of the range ('average' and 'healthiest' controls). The reasons for choosing two such groups were that men with near average values may have included some whose lung function had been slightly affected by noxious influences, while those with very high values were least likely to have been affected by noxious influences, but also cculd conceivably include men who were highly resistant to these influences, and would therefore not be suitable for the comparisons .iir.de in this study. The PVC workers were slightly ever-represented among the cases with low Tloo, though this difference could easily have arisen by chance. Men who had worked on jobs at tha PVC factory which were close to the pressure vessels where exposure to VCM was moat likely to have occurred in the past, ware also slightly over-represented among the cases, and this difference approached statistical significance at conventional levels. There was, furthermore, as association between low gas transfer factor and a history of having workod at the PVC factory before 1?75* This date is important because It was at this time that, in the light of information about some of the potential hazards of VCM, exposure to this gas was drastically reduced. This association between low gas transfer factor and working before 1977 was demonstrated by comparison with the 'healthiest* controls, the 'average' controls showing an intermediate pattern of asaociation not statistically significantly different from the eases. This association with working before 1977 was not found song foundry workers. This conjunction of findings suggests that an unknown environmental or personal factor or factors associated with working at the PVC factory before 1977 might have been responsible for some impairment of the transfer factor in some of these men. The most obvious candidate for suspicion is VCM, exposures to which are known to have UCC 066997 ***** 18. fa been much higher than post-1975 levels. Some support for this is provided by published case reports of VC?' .workers with impairment of gas transfer factor, but proof of association has been lacking CLAIIGE, 1975; DA2KE, 1976). i~nSglSBy though it is possible that many workers throughout the factory were exposed to a lesser degree. It is also possible that exposure to respirable FVC dust may have contributed to the low gas transfer factors, for this dust has been shown in other studies to be associated with impairment of other aspects of lung function (though 1 not the gas transfer factor) and slight chest radiographic abnormalities (KA3TRANGEL0 et_ al., 19^9; SCUTAS et al., 1980). k There was no evidence to suggest that a current risk to respiratory health exists at either the PVC factory or foundry. Some differences m smoking habit were found between cases snd controls tnon-smokers being slightly commoner among controls, and heavier smokers slightly commoner among the cases. The cases tended to start smoking at a slightly younger age. We do not know if these small differences in smoking habit were sufficient to account for tha reductions of gas transfer factor in the cases, but they would seem unlikely to account for the whole of the differences between cases and controls. While the response rate among currently employed workers wes excellent, that for those man who had left the FVC factory was low (39S). If the mas not examined had included either ar. excess or deficiency of men with impaired gas transfer factor compared with the population examined', then the analysis of the distribution of values among the population seen could be unrepresentative to that extent. A similar analysis for another lung function test, forced expired velum in one second, was earried out for the PVC workers only. While some men did have impairment of this test result as would be expected in an industrial population of this kind, no associations with occupation could he demonstrated. ucc 066998 19 5. CONCLUSIONS AND 2LC0KMENDATTCNS We found no evidence of an unexpectedly large number of men with impairment of their lunm gas transfer factor among either PVC factory or foundry employees. There was, however, a small number of men in both factories with impairment of their transfer factor. This eould not be shown to be associated with current working conditions at either factory, but the pattern of results among FVC workers suggested that there was an association between impairment of the gas transfer factor and a history of working in the PVC factory before 1975* There was also evidence that heavy smoking was associated with impairment of gas transfer. These findings give seme support to the hypothesis that work in the PVC factory before 1975 involved exposure to a substance that caused impairment of lung function in a small number of men. The results suggest that more detailed studies of the importance of exposure to vinyl chloride monomer, polyvinylchloride, smoking habit and other possible factors in causing impairment of lung function would be desirable, togtther with a clinical assessment of the extent of lung damage in selected men. ucc 066999 20 ACKNOWLEDGEMENTS This study was carried out with the full co-operation of the management and workforce of Vinatex Ltd., to whom we are grateful for financial support. We also thank the management and workforce of the foundry for their generous co-operation in the study. ucc 067000 21 REFERENCES AGARWAL DK, KAW JL, SRIVASTAVA SP, SETH PK (1978) Some biochemical and histopathological changes induced by polyvinyl chloride dust in rat lung. Environmental Research; 16: 333 - 341 ARNAUD A, PCMMIER de SANTI P, GARBE L, PAYAN R, CHASPIN J (1978) Polyvinyl chloride pneumoconiosis. Thorax; 33: 19 - 25. CHIVERS CP, LAWRENCE-JONES C, PADDLE GK (1930) Lung function in workers exposed to polyvinyl chloride dust. British Journal of industrial Medicine; 37: I1*? - 151. CORDIER JM, FIEVSZ C, LEF3VRS HI, SEVRIN A (1966) Acroostcolyse et lesions eutanees asseciies ches deux ouvriers affeetees au nettoyage d*autoclaves. Cahiers de Medecine du Travail; 4: 14 - 19. COTES JE (1979) Lung function. Oxford: Scientific Publications: 369 - 383* Blackwell CREECH JL, JOHNSON MN (1974) Angiosarcoma of liver in the manufacture of polyvinyl chloride. Journal of Occupational Medicine; l6i 150 - 1J1. DARKE CS (1976) Vinyl chloride and the production of PVC (Discussion). 69* 280. Proceedings of Royal Society of Medicine; FRONGIA N, SPINA2Z0LA A, BUCASELLI A (1974) Lesloni polmonari sperlmentali da inalaxione prolungata di PVC in ambiente di lavoro. Medicina del Lavoro; 65: 321 - 342. GAMBLE J, LID 3, KcMXCHAEL AJ, VAXVEILER RJ (1976) Effect of occupational and nonoceupatlonal factors on the respiratory system of vinyl chloride and other trackers. Journal of Occupational Medicine; 18: 659 ~ 670. HIGGINS ITT (1970) Occupational Factors in Chronic Bronchitis and Emphysema. Review. In; Orie NGH, Van Der Lends B, eds. Bronchitis XU, Proceedings of the Third Int national Symposium on Bronchitis at Groningen, The Netherlands. Springfield (HX.)s Charles C. Thomas, 1970: 83 - 99* UCC 067001 22 LANGE CE, jffes S, STEIN G, VELTMAN G (1973) Die sogtnannte Vinylchlorid-Xrankfceit - eine berufsbedinmte Systerasklerose? International Archives of Occupational Health; 32: 1 - 32. LILIS R, ANDERSON H, NICHOLSON WJ, DAUM S, FISCHBEIN AS, SELIKOFF IJ (1975) Prevalence of disease among vinylchloride and polyvinyl chloride workers. Annals of New York Academy of Science; 246: 22 - 4l. LILTS R, ANDERSON H, HILLER A, SELIKOFF IJ (1976) Pulmonary changes among vinyl chloride polymerisation workers. Cheat; 69: (Suppl. Feb.), 299 - 303* HASTSANGELO G. HANNC M, HARCER G, BARTCLUCCI G1S, GEHIGNANI C, SALADINO G, SIMONATO L, SAIA S (1979) Polyvinyl chloride pneumoconiosis: epidemiological study of exposed workers. Journal of Occupational Medicine; 21: 540 - 542. MEADS F, SAUNDERS MJ, HYETT F, REYNOLDS JA, PEARL N, COTES JE (1963) Automatic measurement of lung function. Lancet; 2: 573 - 575MRC (1976) Medical Research Council Working P-ty on Research into Chronic Bronchitis. Publications Group, Medical Research Council, 20 Park Crescent, London WIN **AL. KILLER A, TEIRSTEIN AS, CHUANG M, SELIKOFF IJ (1975) Changes in pulmonary function in workers exposed to vinyl chloride and polyvinyl chloride. Annals of New York Academy of Science; 246: 43 - 52. PRODAN L, SUCIU I, PZ5LARU 7, ILEA , PA30U L (1975) Experimental chronic poisoning with vinyl chloride (monochloroethane). Annals of New York Academy of Science; 246: 159 - 163. SOUTAB CA, COPLAND LH, THORNLEY PE, HURLEY JF, OTTEKY J, ADAMS WGF, BENNETT B (1980) Epidemiological study of respiratory disease in workers exposed to polyvinylchloride dust. Thorax; 35: 644 - 652. SZCID I, DREJMAN I, VELASKAI M (1967) Study of disease caused by vinyl chloride. Medieina del Lavoro; 58: 26l - 271. ucc 067002 23 VELTMAN G, LANGE CE, JUHE S, STEIN G, BACHNEB U (1975) Clinical manifestations and eours* of vinyl chloride disease. 6 - 17. Annals of New York Academy of Science; 246: VEHTKIN YI, MAMONTOV YB (1970) The state of the bronchi and lungs in workers employed in the manufacture of polyvinyl chloride articles* Gigiena Truda i Professional 'nye Zabolevaniya; 14: 29 - 32. UCC 067003 J TA3IE 1 25 Classification of all jobs at Vinatex into six broad occupational groups. Sroad occupational group Jobs included in group 1 All men working in reactors 1 and 2 * 2 Dryer room 3 operators ** 3 Dryer room Lead., A and A/3 operators 4 Warehousemen, maintenance staff, laboratory staff and drivers *** 5 General stafr who visit plant, e.g. shift supervisors and foressn 6 Kaaagonent and office staff * These nen are no*t likely to have beeu exposed to high concentrations of VCM in the past. "* These men are involved in the bagging of PVC and are probably exposed to higher concentrations of dust than other workers in the dryer buildings. *ss These men are potentially exposed to all raw materials and products. ucc 067004 TABLE 2 26. Classification of foundry jobs into seven broad occupational groups. Occupational <*roup No. Description Jobs included in group 1 Furnace and melt: furnace operator, burner, charger, weirher, skimmer, smelter, slagsan, ladle repairer, concrete liner. 2 Sand and blasting: eoremaker, sand tester, sand mixer, shot blaster, core stripper, knock-out, brick maker. 3 Metalwork: driller, grinder, blacksmith, tinsmith, wagon repairer, rope splicer, cueola repairer, maintenance fitter's mate, maintenance fitter, turner, trainee ir. the training centre, borer, saw repairer, wagon repairer, milling operator, inspector in machine shop, welder. 4 General and other: labourer, patternmaker, plater, platelayer, pipe loader, crane driver, driver, cleaner, technician, trainee, pipe roller, slinger, quality control , joiner, greaser, inspector, saddler, bricklayer, core inspector, despatcher, hydraulic attendant, shunter, plumber, pipe recorder, runner operator, sawyer, staff, power house attendant, canteen, tool room attendant, electrician, storeman, ore crusher, ram driver, safety officer. 5 Paint and dipping: dipper, paint sprayer, painter and decorator. 6 Casting: caster, manhole maker, socket man, machine moulder.. 7 Fattier: fettler ucc 067005 TABLE 3 27. Features of T^co eases, controls and total survey population. Mean (and standard deviations) of age, height, weight and Tlco. Number of men Cases 31 Tlco Grouns Controls Controls (average) (healthiest) 31 31 Total survey population 484 Age (yrs) Kean 41.8 (SD) (10.2) 42.3 (12.5) 40.3 (11.3) 42.2 (11.9) Height (cas) Kean 176.1 (SD) (7.1) 174.0 (6.6) 173.9 (5.6) 173.8 (7.0) Veight (kgs) Mean 82.7 (SD) (13.3) 34.9 (18.5) Tlco Mean (mi/ain, ma Eg) (SD) 22.2 (4.1) 31.8 (2.9) 79.2 (9.5) 37.3 (4-3) 30.2 (12.5) 30.5 (5.9) UCC 067006 TABLE 4 28 Features of FE7t eases, controls and total survey population. Meam (and standard deviations) of age, height, weight, Tico, PE7X and FVC. KuaBer of men Cases 30 Tlco Groups Controls Controls (average) (healthiest) 30 30 Total survey population 264 Age (yrs) It tan (3D) 43.3 (11.0) 41.3 (12.5) Height (eas) Uean (3D) 176.0 (7.4) 174-3 (6.6) Weight (tgs) Uean (SD) 82.2 (13.3) 78.4 (10.1) FEVj (litres) Uean (SD) 2.7 (0.7) J.9 (0.7) FTC (litres) Uean (SD) 4.1 (0.9) 5-1 (0.8) Two Uean (ml/fflin..sniHg) (SD) 29.1* (6.8)* 32.3 (6.0) 42.1 (12.0) 175.9 (8.0) 80.4 (11.5) 4.5 (0.8) 5*9 (0.9) 31.3 (6.5) 42.2 (11.8) 174.3 (7.D S0.4 (12.3) 3.7 (0.9) 4.9 (1.0) 30.5** (6.1)** * Taint Based on 29 oBservationa. ** Taint Based on 262 observations. ucc 067007  m. TABLE 5 Ag distribution of Tlco omb and controla and tha total survey population by euployaant status. CASES PVC currant awn PVC leavers Foundryaan AVERAQE CONTROLS PVC currant pen Foundryaan a HEALTHIEST CONTROLS PVC eurront awn PVC leavers Foundryaan TOTAL POPULATION PVC eurront aan PVC leavers Foundryaan Age ranges in years O - 24 25-34 35 - 44 45 - 54 55 - 64 65* 1 46 222 1 1 1 *1 3 4 1 41 3 1 12 3 2 54 4 2 3241 12 1 2643 9 37 57 35 26 0 4 24 33 19 11 10 1? 1.3 50 o 44 0 rotfti ii 6 12 9 4 18 12 3 16 164 101 219 TABLE 6 30 Employment status of Tlco cases, controls and total surrey population. Number of men in each employment group with percentages in brackets. Four men excluded, see text. PVC Current Workers Total surrey population 164 PVC Leavers 101 Foundry ! t Total 219 434 Cases Controls (average) Controls (healthiest) All 11 ( 3*0 8 ( 53) 12 ( 26) 9 28) 4 ( 27) 18 ( 39) 12 ( 33) 3 20) IS ( 35) 32 (ICO) 15 (100) 46 (100) 31 31 31 93 TABLE 7 Employment status of FEVt cases, controls and total surrey population. Number of men in each employment group with percentages in brackets. Three sen excluded, see text. Rounding error of percentages not adjusted to justify totals. * PVC Current Workers Total survey population 165 PVC Leavers 99 Cases Controls (average) Controls (healthiest) All 14 ( 26) 18 C 34) 21 ( 40) 53 (100) 16 C 43) 12 ( 32) 9 ( 24) 37 (100) Total 264 30 30 30 90 UCC 067009 TittTq 5 Dietritution of observed. Tuso an a percentage of predicted Tlco using Cotes'e regression aodel for non-smokers. Nusbers of nen (percentages in brackets) for the oases, two control groups and total nrvey population* Oases < *i9 Controls (average) Controls (healthiest) Total survey population Tlco % predicted 50-59 60 - 69 70 - 79 80-89 90-99 100 - 109 110 - 119 120 4 (12.9) 11 12 (35.5) (38.7) 4 (12.9) 31 11 13 7 31 (35.5) (41.9) (22.6) 3 (9.7) 14 (45.2) 14 (45.2) 31 4 (0.8) 14 (2.9) 29 (6.0) 75 114 (15.5) (23.6) 120 (24.8) 62 (16.9) 46 484 (9.5) 067010 o o  TABU 9 Distribution ef observed FEV, as a percentage of predicted F2V. using Cotes's regression Model for non-amokera, Nunbers of non (percentages in brackets) for the cases, two control groups and total survey population. 49 FBV, % predicted 50-59 60-69 70 - 79 80-69 90 - 99 100 - 109 110 - 119 >s 120 Total Cases 1 (5.3) 4 (15.3) 5 (16.7) 3 14 (10.0) (46.7) 3 (10.0) 30 Controls (average) 3 (10.0) 17 (56.7) 9 (30.0) 1 (3.3) 30 Controls (healthiest) 1 (3.3) 6 23 (20.0) (76.7) 30 Total survey population 1 <o.4) 4 ( 1.5) 6 (2.3) j9 (3.4) 29 (11.0) 48 (10.2) 74 (28.0) ____ ____ ______ 47 46 (17.8) (17.4) 264 MBU 10 Patella of tha 10 PW factory Ttoo eaaaa with Ui lowaat atandardiiad realdual valuaa of tfcoo. Caao No 1 did Mt conplate the apiraeatrj Uik, Predicted valuaa ara for non-anolcera (Cotaa, 1979), ' Bo. If* Room Booking eatajeonr 1 50 - 3* 0 SB - 2.89 Boo (okoorwf) 2Q.1 Ttco Boo % nwt litres FEVi litres TUB TE5--~ (iNdlflttd) pradietad (observed) (predicted) predicted lltrea FVC * 100 36.6 *.3 - - - - 2 65-69 ft - 2.75 16.1 27.6 51.3 2.1 3.0 69.fi 3.8 55.2 3 35-39 0 - 2.22 20.1 31.* 63.3 3.6 3.8 95.2 5.2 68.9 6 60 - 66 ft - 2.15 20.9 30.5 68.6 1.2 3.5 36.3 3.5 35.1 3 35-39 0 - 2.11 20.ft 32.1 66.6 3.2 3.6 86.9 6.1 77.9 6 55-59 0 - 2.02 16.7 23.9 61.6 2.6 2.7 95.5 3.3 77.9 7 50-56 0 - 2,01 15.9 25.9 59.5 2.7 3.0 90.6 6.3 62.2 ft 35-39 * c - 1.99 23.3 35.5 65.6 6.2 6.1 101.7 5.7 76.3 7 65 - 69 N - 1.92 22.5 10 50-56 0 - 1.ft6 1ft.ft 29.2 29.0 77.0 66.fi 6.1 3.6 3.6 120,1 5.1 80.0 3.3* 107.9 6.7 75.8 nt abbravtatiooa of Booking categorlaa ora aa followai C . currant aookar ft - fit-aaokar fua unlta ara nl/nln, n Bg. B * lifa-loag non-sookar ucc 06701 34. TABLE 11 PVC factory Tlco eases and controls. Mean tines (years) spent in each occupational group with number of sen in brackets. See Table 1 for key to occupational groups. Amongst these cases and controls, the only man who had spent time in occupational group 6 was a current employee, selected as one of the 12 'healthiest' controls. H had spent 1.7 years in this group. CASES Current sen Leavers Number of men 11 8 AVERAGE CONTROLS Current men Leavers 9 4 HEALTHIEST CONTROLS Current men Leavers 12 3 1 3.7 (6) 1.6 (5) 9.1 (3) 0.7 CD 3.3 (5) 1.5 (1) . Occupational groups 2 34 5 0.4 6.1 9.0 9.7 (5) (3) (4) (2) 0.8 11.8 (6) (D - 1.1 6.8 7.1 12.3 (3) (D (4) (1) 0.4 (4) - 1.8 CD - 1.2 io.8 7.3 3.3 (8) (D (2) (2) 0.5 (3) - - m UCC 067013 i TABLE 12 35. Foundry Tuco cases and controls. Mean times (years) spent in each occupational group with number of men in brackets. See Tahle 2 for key to occupational groups. Number Occupational groups of men 1 2 3 4 5 67 12 7.3 3.0 12.3 4.0 3.2 11.4 1.0 (4) (2) (5) (7) (2) (2) (D AVERAGE CONTROLS 18 HEALTHIEST COMTHCLS IS 4.6 16.1 (3) (5) 30.4 (1) 9.4 (9) 13-4 (5) 4.5 (3) 12.7 (3) * 12.5 (8) 7.4 10.6 2-5 (13 (5) CD 11.6- (6) - TABLE 13 FVC factory FEVj cases and controls. Kean times (years) spent in aeh occupational group with number of men in brackets. See Table 1 for key to occupational groups. * Number of men 1 Occupational groups 234 5 6 Current men Leavers U 5-5 1.3 (7) C8) 16 2.1 0.8 (8) C9) AVERAGE CONTROLS Current men Leavers 18 3.2 1.2 (10) (10) 12 1.3 0.9 . (5) (7) HEALTHTSST CONTROLS Current man 21 6.4 1.2 CIO) OO) Leavers 9 1.2 0.3 (2) (6) 4.3 (2) 4.7 (3) 5-2 CD 4.1 (V 0.7 (2) 6.1 6.8 3.8 (6) (2) CD 1.0 - (2) - 7.6 7.7 5.0 (5) (2) (2) 1.2 3.1 - C3> (2) 7-2 3.6 2.6 C9) (3) (2) 2*1 ucc (2) 067014 36 TABLE 14 For Tvco analysis, the distribution of numbers of FVC cases and controls who had worked at the FVC factory before 1975 and only after 1975* Pre 1975 Post 1975 Total Cases 17 2 Average Healthiest Controls Controls 11 5 2 10 Total 33 14 19 13 15 47 TA3IE 15 PVC factory Tlco cases. Number of men within each age group and duration of pre-1975 employment category. Ties of Duration of mnployment maployment Pxe 1975 Post 1975 Total < 2 yr 2 - 4 7* W > 4 yr - 1 1 0 1 25-34 Igm (yrs) 35-44 45-54 55-64 65 + li Total 1 341 9 12 3 4 15 12 2 6 8 1 1 19 UCC 067015 TABLE 16 PVC factory Tlco average controls. Number of men within each age group and duration of pre-1975 employment category. 5S i ir> 3 i tr\ CM 3 l o Time of Luxation of employment employment Pre 1975 Post 1975 Total ' < 2 yr 2 - 4 yr > 4 yr * - Age (yrs) Total 35-44 45 - 54 55 - 64 65 + 'i 1 2 21 1 12 11 2533 4 3 4 2 13 TABLE 1? PVC factory TLco healthiest controls. Number of men within each age group and duration of pre-1975 employment category. Time of Luxation of Age (yrs) employment asployment 0-24 25-34 35-44 Pre 1975 < 2 yr 2 - 4 yr > 4 yr 1 1 1 i Post 1975 - 2323 Total 3 524 -- Total 55 - 64 Sy * 2 4 1 it 10 1 15 UCC 067016 38 TABLE 18 For FEVX analysis, the distribution of numbers of FVC esses and controls who had worked at the PVC factory before 1575 and only after 1975* Pre 1975 Post 1975 Total Cases 23 7 30 Average Healthiest Controls Controls 18 19 12 11 30 30 Total 60 30 90 TABLE 19 For Two analysis, the distribution of numbers of foundry eases and controls who had worked at the foundry before 1975 and only after 1975- Pre 1973 Post 1975 Total Cases 8 4 12 Average Healthiest Controls Controls 13 12 54 18 16 Total 33 13 46 IJCC 067017 TABLE 20 39 For Ttco analysis, the distribution of PVC factory eaaas and controls who had worked with different polymers. Cases Average Controls Healthiest Controls Total Ehzulsion and suspension Suspension only Neither suspension nor emulsion 6 9 4 8 4 18 3 11 23 2 06 Total 19 *13 15 47 TABLE 21 For FEVj analysis, the distribution of PVC factory cases and controls who had worked with different polymers. ttauislon and suspension &Lspension only Neither suspension nos emulsion Cases Average Controls 87 18 13 4 10 Bealthieet Controls Total 10 25 13 44 7 21 Total 30 30 30 90 1 ucc 1 067018  TABLE 22 Uo. PVC factory Tlco eases and controls. Number of men who have worked in noxious occupations with mean number of years spent by these men In brackets. See Appendix 2 for list of 'other' noxious occupations. CASES Number of men 19 AVERAGE CONTROLS HEALTHIEST CONTROLS 13 15 Steel 8 (5.5) Noxious occupations Chemicals j Coal 7 (1.9) 7 (10.1) 03 6 (9.6) (6.9) 3 (6.1) 0 2 (17-4) Other 8 (11.5) 7 (i0.4) 8 (V<if TABLE 23 PVC factory 7SV. cases and controls. Number of men who have worked in noxious occupations with mean msber of years spent by these men in brackets. See Appendix 2 for list of 'other' noxious occupations. Number of sen 30 Steel Noxious occupations Chemicals Coal 10 (4*6) 5 (4.0) 16 (15.7) Other 16 (13.2) AVERAGE ' CONTROLS 30 7 6 9 15 (9.8) (14.0) (6.3) (7.5) HEALTHIEST 30 4 CONTROLS (17.8) 4 (9-1) 11 (13.6) 18 (8.9) t : ucc 057013 TABLE 24 41. Foundry Tlco cases and controls. Number of men who have worked in noxious occupations with mean number of years spent by these men in brackets. See Appendix 2 for list of 'other* noxious occupations. Number of men Steel Noxious occupations Chemicals Coal Other CASES 12 1 (3.0) 0 (0.0) 3 (5.4) 5 (1-3) A7UU.GE COhTBOLS 18 2 (9.6) 0 (0.0) 4 (9.0) a (10.9) HEALTHIEST cornois 16 2 (4-7) 0 (0.0) 5 (2.9) 5 (7-2) UCC 067020 TABT.7. 25 U2. Smoking habits of Tlco cases, controls and total surrey population. Number of men in each smoking category with percentages in brackets* NonSmoker Current Smoker Ex-Smoker Total Cases 3 (9.7) 20 (64.5) 8 (25-8) 31 Controls (average) 4 (12.9) 15 (48.4) 12 (38.7) 31 Controls (healthiest) 7 (22.6) 15 (48.4) 9 (29-0) 31 Total surrey population 109 (22.5) 234 (48.4) 141 (29.1) 484 TA3IS 26 Smoking habits of 7E71 cases, controls and total surrey population. Number Ox men in each smoking category with percentages in brackets. Cases Controls (average) Controls (healthiest) Total snrrey population NonSmoker 5 (16.7) Current Smoker 13 (43.3) 7 (23.3) 15 (50.0) 9 (30.0) 12 (40.0) 59 (22.3) 125 (47.4) te-Smoker Total 12 (40.0) 3C 8 (26.7) 30 9 (30.0) 30 80 (30.3) 264 UCC 067021 Number of men ucc 067022 w ^ m m h o h m w ^ 01 o> -4 **5- | E2 PVC factory t. iEE0 P Cases 0 10 20 30 40 50 + No. ofcigs. WWC22 "T 'Healthiest' controls. Fig. 3 Number of cigarettes smoked on weekdays by FEVj cases and 'healthiest' controls who are1 current smokers. Number of men 0 0 10 20 30 40 50 + No. of cigs. Fig. 4 Number of cigarettes smoked on weekdays by Tlco cases and 'healthiest' controls, at the PVC factory and the foundry, who are current smokers. UCC 067023 t* o io n o h hm nv n Fig. 5 Number of cigarettes smoked per day at weekends by Ttco cases and 'healthiest' controls, at the FVC factory and the foundry, who are current smokers. ucc 067024 *9. 23 PVC factory __ Foundry c 4) U Cl _______Cases 1 No. of cigs. 2 'Healthiest' controls. Fig. 6 Maximum number of cigarettes regularly smoked per day by Tuco cases and 'healthiest' controls, at the PVC factory and the foundry, who are current smokers. Number of men Fig. 7 Maximum number of cigarettes regularly smoked per day by FEV^ cases and 'healthiest' controls. ucc 067025 Number of men 51- (b) 0PVC factory g. (_) Foundry 7 6- 5- 4c 3. 't 0PVC factory Foundry E 2- <141516171819 2021 > *3 1- 4U) n. Age (yrs) -a 0 < 1415 161718 19 2021 + i rer 2 3 ^"0-------- 'Healthiest' I 1 ITW^J Kd controls Lj|| ^ 2 3- 4- 5- Cases Age (yrs) 'Average' controls Fig. 8 a) Age when started smoking cigarettes, for TlCO cases and 'healthiest' controls at the PVC factory and the foundry, who are current smokers. b) Age when started smoking cigarettes, for Tico cases and 'average' controls, who are current smokers. (a) (b) 0 PVC factory j" 0 PVC factory 4- 3- 9 |2- s 6 1. * Cases a . Cases U 0 <1* BBCT 181920 21 Age (yrs) & 0 < 14 S 16 171819 20 21 + Age (yrs) i * 1 2- WTOm2ZZ3~ 'Healthiest' u controls 2- 'Average' controls 3- 3- 4- 4* Fig. 9 a) Age when started smoking cigarettes, for FEV. cases and 'healthiest' controls, who are current smokers. b) Age when started smoking cigarettes, for FEV. cases and 'average' controls, who are current smokers. UCC 067026 53 APPENDIX 1 SMOKING CUE5TI0NNAIFE 1 Do you smoko? If NO 1* Hats you ever smoked as orach as one cigarette a day (or one cigar a week or as ounce of tobacco a month) for as long as a year? If NO to both parts of question 1, emit remaining questions on smoking. 2 Bow old were you when you started smoking regularly? 3 How old are you aow7 4 Do (did) you smoke manufactured cigarettes? If YES 4a How many do (did) you usually smoke per day on weekdays? 4b How many do (did) 70U usually smoke per day at weekends? 4 What was the greatest number of cigarettes you ever smoked regularly per day? 4d For how long were you cooking that many? 4e Since starting smoking tobacco have there been periods during which you did not smoke cigarettes? If TZSt for how long altogether were you not sacking cigarettes? 4f (Apart from those times) What was the least number of cigarettes you ever smoked regularly per day? 4g For how long were you smoking that many? 5 Do (did) you smoke hand-rolled cigarettes? If YES 5a How ouch tobacco do (did) you usually smoke per week in this way? UCC 067027 APPENDIX 1, page Z 5^. Do (did) you smoke a pipe? if ns 6a How much pipe tobacco do (did) you usually smoke per week? Do (did) you smoke small cigars? If YES 7* How many of these do (did) you usually smoke per week? Do (did) you smoke other cigars? If YES Sa How many of these do (did) you usually smoke per week? For ex-smokers: When did you last give up smoking? ucc 067028 APPENDIX 2 NOXIOUS OCCUPATIONS In the classification of noxious occupations the following jobs were included in the category 'other'. Although it is recognized that some of the jobs included in this category are not widely recognised as 'noxious', it was considered that they may on occasions be associated with health hazards and should therefore be included in the classification of noxious occupations Brewing Baker Flour miller Farm worker Vocd cutter/sawmill worker Construction worker Bricklayer Plasterer Quarryman Paper mill worker Electrician Joiner Glassworker Velder Scrap burner Foreman Coking plant worker Furnace operator Car body reoairer Paint aprayer . Painter/deeorator Tarmacadam exposed worker* ucc 067029 56. APPENDIX 3 Development of the multiple linear regression model used in the analysis of the data frost the total survey peculation Preliminary multiple linear regression analysis indicated the anticipated relationship between Tlco and age, height and weight and between FEVt and age and height. These relationships were looked at again after allowing different intercepts and age slopes for non-smokers and all smokers whether current or ex-smokers. For the Tlco analysis, this was a significant improvement in the amount of variation explained. However, this group of smokers did not have a significantly lower mean Tlco after age, height and weight had been taken into account than non-smokers and the age slopes were similar. The model used for Tlco (but not the FVt modal) was. further improved by introducing different intercepts sr.d age slopes for three categories of smoking, non-smokers, current smokers and ex-smokers. This analysis showed that for ex-smokers the mean valut of Tlco was significantly higher than that of current smokers (P < 0.05) but that they experienced a greater loss of Tlco with age than current and non-smokers although these differences were not statistically significant (Table '!)* Further expansion of this model by allowing different intercepts and age slopes for -the different employment categories (current and former employees at the FVC factory and foundry employees) within the three smoking groups did sot make a significant improvement to the model. However, this analysis did indicate that the mean Tlco level for leavers from the PVC rectory who were currant smokers was significantly lower (P < 0.1) .then current FVC factory employees who were non-smokers. However, the ago slope of this group did not differ significantly from that of current PVC factory employees who were non-smokers. Hence the modal used was the one in which different intercepts and ago slopes were allowed for the three amokiag groups. For reasons of eonsistancy the FEVt analysis was also basad on this same modal although there was no significant improvement In the amount of variation axplalned as thsre had been for the Tlco analysis. Th results for FZV1 analysis show that thsre was a significant difference (P < 0.1) in the rate of loss of FEVt with age between non-smokers and current smokers who experienced a greatar rate of loas of IVfx (Table 2). UCC 067030 APPENDIX 3. peg* 2 EASES 1 57. Regression for Tlco (al/min. mm Hg) allowing different intercepts and age slopes for three bqW ng groups. Variables Age Height Weight Units Tears cm kg Mean 42.2 173.8 80.2 Constant for no*aokers Regression coefficient -0.2246 0.1552 0.0572 Constants (intercepts') 10.3052 t -5.74 4-74 3.23 P < 0.001 < 0.001 < 0.002 Effeet on intercept ofi Current smokers Es- smokers Effect on age slope fort Current smokers Ee-ackers -2.5288 1.4554 - -0.0154 -0.0537 -1.34 0.69 -0.33 --1.08 MS MS HS US . TABLE 2 Regression for 7E71 () allowing different intercepts and age slopes for three smoking ^oupc. Variables Age Height Weight Units Tears cm kg Mean 42.2 174.3 80.4 Constant for noo-snokere Regression eoefficient -0.0309 0.0420 ' 0.0003 Constants (Interesets) -2.1725 t -4.55 7.13 0.09 P*. < 0.001 < 0.001 . HS Effect on Intercept aft Current ackers Bo-ackers 0.4209 0.2675 1.24 0.75 ES HS Effect on sge slope fors Current aoke Knacker. * .-0.0149 -0.0096 -1.81 -1.13 < 0.10 HS UCC 067031 * n ucc 067032