Document zbMJMv1xL0r3ekdQdr7grmax6

ORDER-'18150 11 ITEMS MAIL TO: BORDEN INC ATTN: REGULATORY COfIF'LIRNCE 960 KINGSMILL PRKWY COLUMBUS DH 439 : ..v 5-770 9*40 FILE 153 ITEM 3 1661 771911 " AN ASSESSMENT OF HAND THERMOGRAPHY IN VINYL CHLORIDE WORKERS ' U ILL I RMS: DM? ROBERTS E? EVANS K T J SDC OCCUR MED > RPR 1977n <> P57-6E* ISSN ; JOURNAL CODE: K5B U? BOR 010929 - v* ^ "S% ^/i/ *'***'.*JV(,- i.tefj 7. 5or. Occup. Med. (1977) 27, 57-62 Printed in Great Britain An Assessment of Hand Thermography in Vinyl Chloride Workers D. M. J. WILLIAMS Medical Officer, BP Chemicals Limited, Sully, South Glamorgan ERNEST ROBERTS Chief Technician, Department of Radiology, Welsh National School of Medicine K. T. EVANS Professor of Radiology, Welsh National School of Medicine ----- Sitmmart Since Raynaud's phenomenon is an early and integral part of the condition of acro-osteolysis in vinyl chloride workers, a survey involving 143 workers and 36 controls was carried out to assess the feasibility of using hand thermography to ^^^ct changes from the normal pattern of vascularity. ^|^rom the almost identical results between the control and the exposed subjects, and between groups within the exposed population, it appears that there is no detectable difference in thermographic appearances. Introduction In the general population, the syndrome of inter mittent ischaemia of the Angers and associated skin changes, first described by Raynaud in 1862, is divided into primary and secondary types, the condition being considered secondary if an associ ated or precipitating pathological process can be found. Tlie aetiology of the primary or idiopathic type is unknown, but is related to an abnormal vascular reactivity to cold, although mental stress, smoking and increasing age may also exacerbate it. Secondary Raynaud's disease may be associated with a wide variety of underlying diseases of the skeletal, vascular, endocrine and central nervous systems, severe infections, mechan ical trauma and collagen diseases (Beeson and McDermott, 1963; Velayos et al., 1971; Leading Article, British Medical Journal, 1972). The milder primary cases are not uncommon, with women affected ten times as often as men (Gifford and Hines, 1957). Although other idiopathic and familial syn- iomes have been described in association with acro-osteolysis (Andren et al., 1962; Cheney, 1965), occupational acro-osteolysis (AOL) was first recognized as a clinical entity in 1963 (Suciu et al., 1963), and appears to be confined almost exclusively to cleaners of reactor vessels in which vinyl chloride nomomcr (VCM) is polymerized to polyvinyl chloride (PVC) (Wilson et al., 1967; Harris and Adams, 1967; Dinman et al., 1971), and only one case is recorded in a man who, while he had never actually been a reactor cleaner, had worked in the reactor buildings with a similar exposure to VCM (Stewart et al., 1975). Occupational acro-osteolysis is described as a symptom complex consisting of a Raynaud's-like phenomenon involving the hands, changes of the skin, simulating systemic sclerosis of the bands and forearms, and osteolytic and sclerotic lesions of the bones, particularly in the hands and feet, and the sacro-iliac joints (Markowitz et al., 1972). The lower pole of the patella and the styloid processes of radius and ulna can also be affected (Dinman et al., 1971). The incidence of the disease is not accurately known; Wilson observed 31 cases in 3000 workers involved in vinyl chloride manufacture and polymerization (Wilson et al., 1967), and Dinman reported 25 definitive cases in 5011 employees in 32 plants throughout the United States and Canada, with 16 other men considered suggestive but not definitive cases (Dinman et al., 1971). Markowitz found two cases in a plant employing less than 100 people, (Markowitz et al., 1972). The BOR 010930 SETS-5 gaav - 58 OCCUPATIONAL MEDICINE incidence is, however, believed to be relatively low --less than 3 per cent of all production workers who had at one time worked as reactor cleaners, and because of this it has been suggested that a personal idiosyncracy is possibly one of the factors in its aetiology (Wilson et al., 1967). Furthermore, it seems that the Raynaud's phenomenon is usually the first of the triad complex to appear, and that it is irreversible even if the patient is removed from exposure to VCM; probably the skin changes are also irreversible, though neither are invariably progressive, but recovery of the bony lesions has been reported (Markowitz et al,, 1972; Rety et al., 1974; Williams and McLachlan, 1976). Considering, therefore, the importance of the Raynaud's phenomenon, both as an integral part of the condition and as a possible precursor of established acro-osteolysis, it is apparent that early detection of vascular insufficiency by a provocation test might have a part to play in the screening of men about to be engaged as vessel cleaners, or of those already so engaged. Patients and Methods Radiographs of the hands of polycleaners and other production workers exposed to VCM have been taken regularly since 1971 at a factory producing in excess of 130 000 tonnes of PVC annually. It was decided that in addition to the radiography sessions in May, 1975, thermography of the hands would be done as well, on a voluntary basis, each of those men eligible by virtue of their exposure history having been given a letter explaining the nature and purpose of the project, and asking for their cooperation. Plant management and shop stewards were also given a somewhat fuller account personally by one of us, in order to enlist their help in promoting the project and to enable them to explain it to employees who might come to them with questions or doubts. In all, 176 men were eligible to participate, and of those, 169 volunteered (96 per cent). In the event, 26 men were compelled to withdraw, due to absence on sick leave or holidays when the sessions were held, leaving 143 subjects finally (81 per cent of those eligible). Each man was given in advance two detailed questionnaires* The first sought information on 'Copies of these questionnaires are available on request from Dr D. M. J. Williams. symptoms which might be attributable to vasci insufficiency of the hands, and if the patient kr of similar history in his immediate family. 7 second questionnaire concerned smoking hab and the men were asked not to sm ke on the c of the test. From this questionnaire we found t; of the 86 men who habitually smoked, 34 (39-5 ; cent) were able to refrain. A nurse from the factory medical centre v present at the sessions so that any man who h experienced difficulty with the rather elabor. questions could be helped to complete the for as he handed them in. The sessions were held in a research laboratc where the room temperature could be regulate and throughout the sessions remained at betwe 19C and 22C (66-2 and 71-66F). The weath on all four days of the experiment was seasonal mild, and the men had their hands X-rayed fir Consequently they were in the building for abc 10 minutes before the thermography procedu was started. Technique Thermography records the temperature variati< emitted by the body itself within the infra-red pa of the spectrum. The apparatus used in the survey was the Aj Thermovision System, consisting of an infra-re camera and display unit. It permits the insta; taneous display of the heat emitted by the boc on a cathode-ray tube, and this display w; recorded greytoned on Polaroid film. The right hand of each vinyl chloride worker we placed on an armrest and the Thermovision disph adjusted to visualize all digits. The whole of tl hand was then immersed in a thermostaticali controlled water bath at 19C for 10 seconds, has been shown (Lewis, 1946) that this is sufficier to produce detectable changes in normal subject The hand was then removed and rapidly wiped dr; The hand was then repositioned on the armrei and constant visualization of the cathode ra screen commenced. Immediately a heat retur was noticed in any portion of the hand or finger the time was recorded as Tl on one of three stop watches which had been activated immediate! the hand was removed from the water (Fig. 1). Th next return was recorded as T2 (Fig. 2). The fina return time, T3, was noted when either all fingertip became visible (Fig. 3) or 10 minutes had elapsed BOR 010931 HAND THERMOGRAPHY 59 . i` This arbitrary time was chosen because in a preliminary study of controls it was found that he mean return time was 4 minutes 29 seconds. Normal thermogram in this context refers to the return of heat to all the digits within 10 minutes; abnormal thermogram refers to the failure of heat BOR 010932 60 OCCUPATIONAL MEDICINE Table /. Results of thermography in 143 men and 36 controls Total number in group `Normal' thermogram 'Abnormal* thermogram No `full' reaim No return at all Exposure group A BC 72 . 54(73:.) 18(25%) 7 (9-7%), 11 (15-3%)) 25 - 33 3 23 (69-7%) 3 (100%) 10(30-3%) 0 5 (15-2%)) 5 (15-2%)) 30-4% D 35 24 (68-6%) 11(31-4%) 6(17-1%)) 5(!4 3%)j 31 Controls 56 45 (80%) 11(20%) 7(12-5%)) 12(21%) \ 33 to return to all digits within 10 minutes (Fig. 4). The mean return for vinyl chloride workers was 3 minutes 33 seconds. It was found possible to examine about ten patients per hour, which dees not of itself rule out the technique for mass screening programmes. Results VCM-exposed Subjects From factory records it is possible to classify those who took part into four groups in descending order of magnitude of peak exposure to VCM. A. Vessel cleaners for one year or more. B. Other polymerization workers for one year or more. C. Monomer process workers for one year or more. D. Other exposed workers. The men remain classified in the highest exposure category that they achieved in the course of their employment. Since exposure in all jobs is less than 20 ppm for the past 18 months, this is only a valid comparison of their relative exposure histories prior to mid-1974. The 143 volunteers were distributed among the exposure groups thus: A. 72 (50-3 per cent). B. 33 (23 per cent). C. 3 (2-1 per cent).* D. 35 (24-5 per cent). Table I shows the results of thermography in these four exposure groups. There were no radio logical changes in the hands in this series suggestive of acro-osteolysis. From this table it can be seen that there was no significant difference in the results between the exposure groups nor between each individual group and the overall test population; in the case *VCM has not been produced at this plant since December, 1970. of Group C, there were only three subjects, and fact the highest VCM-exposed group most dost matched the control subjects. `Abnormal' thermograms were recorded by of the 86 men who smoked (26-7 per cent) ai by 14 on the 52 non-smokers (26-9 per cent). From the questionnaires, it was found that men considered that they had symptoms Raynaud's phenomenon, but 11 of these m< (73-3 per cent) had `normal' thermograms, ar these 11 included 3 men who had reported in the questionnaire that in each case all ten of the fingers were so affected. However, in the other subjects, thermography did show a delayed retu (Table II), although there is no clinical eviden that these men do actually have Raynaud phenomenon, and in 2 cases it is possible that tf thermogram was affected by smoking just befo the test. Only one man was aware of a family history Raynaud's phenomenon, but he did not consid himself to have the condition, and indeed h thermogram was quite normal. Controls The control subjects comprised 56 male hospit staff volunteers, and were examined by an identic procedure. Forty-five (80 per cent) returrn `normal' thermograms. Discussion It is known that there is an increased incidence < Raynaud's phenomenon in the general populatic both with increasing age and with smokin Tables III and IV show that this was reflected : both controls and VCM-exposed workers, altbou^ it is of interest that the incidence did not increa. until an older age group in the exposed worker The reason for this is not known and the numbe involved are probably too small for speculation c HAND THERMOGRAPHY 61 Table II. Correlation between questionnaire and thermography Patient 1 Patient 2 Patient 3 Patient 4 Exposure Group A B D D Age Smoker Fingers affected . Byquest.onna.rt By thermography in the right hand 53 No, for Middle, right and 8 months left hands 48 Yes, including All, both hands before test 48 No, for 3 years Index, middle and ring, right hand 26 Yes, including Index, middle, ring before test and little, left hand All digits affected Index and middle only affected Index, middle and ring All affected Table III. Abnormal thermograms by age groups Age 20-29 30-39 40-49 50-59 VCM workers T . Abnormal ,otal thermogram 40 6 (15%) 39 5(12%) 40 6(10%) 24 6(25%) Controls Total Abnormal thermogram 37 7 (19%) 15 3(20%) 2 1 (50%) 2-- Table IV. Abnormal thermograms by smoking habit VCM workers Nonsmoker - Smoker (59) (84) Controls Nonsmoker Smoker (36) (20) Return zero T1 14(23%) 12 (14%) 3( 8%) 1 (5%) Non-return T2 10 (16%) 12(14%) 4(11%) 3(15%) Non-return T3~ 19(31%) 23 (27 %) 6(17%) 4(20%) the point to be worthwhile. Similarly, with regard the effect of smoking, though the patterns are Bkallel, detailed comparisons would not be valid with these numbers. With regard to acro-osteolysis, it appears likely that, although the bony lesions can heal in time if exposure to VCM ceases, the Raynaud's component will persist (Williams and McLachlan, 1976). As we have explained earlier in this paper, it has been customary for long-term health surveillance for delayed effects to keep a man in the highest exposure category experienced in his working life at the factory. By doing this, one remains alert for the possibility of late-onset developments from previous higher exposures. Nevertheless, in this plant, men change jobs as part of their normal career progress, from the higher exposure of vessel cleaning where most new entrants start their work, to production processes downstream and even, not infrequently, to supervisory work. This practice is in contrast to that of other plants where a two-tier entry tends to place men for longer periods in either labouring jobs (vessel cleaning) or line production work, with less pro gression from the former to the latter. It is, how ever, relatively simple in this factory to label the men by their present jobs, as well as by their previous or highest exposure work. If this is done, while the figures reflect job progression {Table V), the pattern holds virtually steady. It therefore seems most unlikely that there is any delayed effect, in terms of the development of Raynaud's phenomenon, let alone the full syndrome of acro-osteolysis, resulting from higher exposures in former years. However, the unique case described by Stewart et al., (1975), wherein a worker developed AOL without ever having been a vessel cleaner, en courages the belief that it is not only exposure levels, but exposure in an idiosyncratic individual that produces AOL, and therefore surveillance in some form of exposed workers cannot yet be discontinued, despite the creditably low levels of exposure now achieved in the industry. Many of the men who volunteered for the survey had had upwards of 15 year's service in the industry, at a time when exposure levels were markedly higher than are found today in any jobs relating to VCM. From the summer of 1974, it is doubtful if any worker has been consistently exposed to VCM above 25 ppm, and therefore any future effects in terms of Raynaud's phenomenon, as a precursor to, or an essential component of, acroosteolysis, are going to be an unlikely finding clinically. Since it is clear that questionnaires are relatively unhelpful, there seems to be no substitute, in our present state of knowledge, for regular hand 62 OCCUPATIONAL MEDICINE Table V. Comparison of results of thermography by placing exposed workers in either present job or highest exposure categories Present job Highest category Category Total Abnormal Total Abnormal in group thermograms in group thermograms A 16 5(31 25%) * 72 B 97 26 (26-8*4) 33 C0 0 3 D 30 8 (26-6%) 35 Controls 56 11 (20%) 56 18 (25%) 10(30%) 0 11 (31%) 11 (20%) inspections by trained medical or nursing staff, and that firm proof of Raynaud's phenomenon must still rest upon a clinical observation of its occurrence. Without this safeguard, as Binns (1975) pointed out, men are at risk of being unjustifiably removed from their jobs. Acknowledgements We wish to thank Mr W. B. N. Bomford, FRCS, Chief Medical Officer, British Petroleum Company Limited, for permission to publish this work; also to thank the specialist staff of BP Chemicals Limited, Barry Factory, and men from this factory who volunteered for the survey. Dr R. McL. Archibald of the National Coal Board Medical Service, and Dr C. H. B. Binns, Medical Officer, BP Chemicals Limited, Baglan Bay, kindly gave valuable advice during the preparation of this paper. Mr R. LI. Davies kindly prepared the illustrations. REFERENCES Andren L., Dymling J. F,, Hogeman K. E. et al. (1962) Osteopetrosis acro-osteolytica. A syndrome of osteo petrosis, acro-osteolysis and open sutures of the skull. Acta Chirurgica Scandinavian 124,496. Beeson P. B. and McDermott W. (1963) Ctett-Loeb Textbook of Medicine, 11th ed. Philadelphia, W. B. Saunders, p. 787. Binns C. H. B. (1973) Personal communication. Cheney W. D. (1965) Acro-osteolysis. American Journal of Roentgenology, Radium Therapy and Nuclear Medicine 94,494. Dinman B, D., Cook W. A., Whitehouse W. M. et al. (1971) Occupational acro-osteolysis. I. An epidemiological study. Archives of Environmental Health 22, 74. Gifford R. W. jun. and Hines E, A. jun. (1957) Circul. 16, 1012. Harris D. K. and Adams W. G. F. (1967) Acro-ostec occurring in men engaged in the polymerization of chloride. British Medical Journal 3, 712. Health and Safety Executive (1975) Vinyl Chloride, t of Practice for Health Precautions. Temporary For February 1975. Baynard's House, London, Health Safety Executive. Leading Article (1972) Raynaud's Phenomenon. Bt Medical Journal 3, 782. Lewis Sir Thomas (1946) Vascular Disorders of Li London, Macmillan. Markowitz S. S., McDonald C. J., Fethiere W, et al. (1 Occupational acro-osteolysis. Archives of Dermatc 106, 219. Raynaud M. (1862) On Local Asphyxia and Symmet Gangrene of the Extremities. (Irans. Thomas Barli London, New Sydenham Society (1888). Rety J., Lazard P., Berrod J. et al. (1974) Contributioi infra-red thermography to diagnosis and supervisioi disorders due to exposure during vinyl chloride polym ation processes. (Table 52 (acro-osteolysis) of the Sche of Occupational Diseases.) Archives des Maladies Pri sionnetles 35, 733. Stewart J. D., Williams D. M. J. and McLachlan M. S (1975) Acro-osteolysis in a polyvinyl chloride worker ' an atypical industrial history. Journal of the Societ; Occupational Medicine 25, 103. Suciu I., Drejman I. and Valeskai M. (1963) Investiga of the diseases caused by vinyl chloride. Medicina Inu (Bucuresti) 15,967. Velayos E. ., Robinson H., Porciuncula F. E. U. et (1971) Clinical correlation analysis of 137 patients ' Raynaud's phenomenon. American Journal of the Mec Sciences 262, 347. Williams D. M. J. and McLachlan M. S. F. (1976) Hea of phalangeal defects in acro-osteolysis. Journal of Society of Occupational Medicine 26, 98. Wilson R. H.. McCormic W. E., Tatum C. F. et al. (IS Occupational acro-osteolysis. Journal of the Ameri Medical Association 201, 377. Requests for reprints should be addressed to: Dr D. M. J. Williams. BP Chemicals International Ltd, Sully, Penarth, So Glamorgan CF6 2YU.