SWORD '97: Surveillance of work-related and occupational respiratory disease in the UK

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1 Occup. Med. Vol. 8, No. 8, pp. 8-85, 998 Copyright 998 Lippincott Williams & Wilkins for SOM Printed in Great Britain. All rights reserved /98 SWORD '97: Surveillance of work-related and occupational respiratory disease in the UK D. J. Ross, H. L. Keynes and J. C. McDonald Department of Occupational and Environmental Medicine, National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW 6LY, UK SWORD is one of seven clinically based reporting schemes which together now provide almost comprehensive coverage of occupational diseases across the UK. Although SWORD is now in its tenth year, participation rates remain high. Of an estimated, new cases seen this year,,0 (6%) were of occupational asthma, 978 (5%) of mesothelioma, 79 (0%) of non-malignant pleural disease, 6 (9%) of pneumoconiosis and (6%) of inhalation accidents. Incidence rates of occupational asthma were generally highest among workers in the manufacture of wood products, textiles and food (particularly grain products and crustaceans) and additionally, in the production of precious and non-ferrous metals, rubber goods, detergents and perfumes, and in mining. Health care workers were noted to have a surprisingly high incidence of inhalation accidents. Occupational asthma attributed to latex has increased dramatically; the highest rates are among laboratory technicians, shoe workers and health care workers. Key words: Occupational respiratory disease; surveillance; epidemiology. Occup. Med. Vol. 8, 8-85,998 Received 8 May 998; accepted in final form 6 May 998. INTRODUCTION The SWORD scheme has entered its tenth year, and continues to provide reliable estimates of the incidence and patterns of occupational respiratory disease seen by chest physicians across the UK, as well as supporting several research projects. It is now complemented by six other clinically based occupational disease surveillance schemes, involving occupational physicians (OPRA), dermatologists (EPIDERM), communicable disease specialists (SIDAW), audiologists (OSSA), rheumatologists (MOSS) and psychiatrists (SOSMI).* Specialists in respiratory disease report directly to SWORD, and those in occupational medicine report indirectly via OPRA. Closer co-ordination of all these schemes within an occupational disease information network (ODIN), based in Manchester, was initiated in April 998. PARTICIPATION Of nearly 0 participating chest physicians, 5 are members of a 'core' group and report monthly; the remainder are allocated at random to report in only one of monthly samples. In the core group an average of 78% returned report cards and in the remainder 76% did so. From the parallel scheme for over 600 occupational physicians (OPRA), 0 in their core group report monthly and an average of 95% returned cards; of the remainder who report in one of monthly samples, 87% did so. Participation by chest physicians in the sample has thus regained the levels seen previously, which may be due to telephone and written reminders introduced over the last two years. *OPRA: Occupational physicians reporting activity; SIDAW: Surveillance of infectious disease at work; OSSA: Occupational surveillance scheme for audiologists; MOSS: Musculoskeletal occupational surveillance scheme; SOSMI: Surveillance of occupational stress and mental illness (still at the pilot stage). Correspondence and reprint requests to: Dr D. J. Ross, Epidemiological Surveillance Unit, Department of Occupational and Environmental Medicine, National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW 6LY, UK. DATA SUMMARY By 6 March 998, SWORD had received reports of,5 cases first diagnosed by participants in 997. When the sampling fraction was applied this gave an estimated total of, new cases (Table ). Occupational asthma remained the most frequently reported disease with slightly fewer cases than in the previous year,0 as Downloaded from on November 07

2 8 Occup. Med. Vol. 8, 998 Table. Summary of cases reported to SWORD in 997, with estimated totals Group Occupational physicians 'Core' 'Sample' Chest physicians 'Core' 'Sample' Total Male (%)' Mean age (years)" Estimated total 996 total Allergic alveolitis Asthma Bronchitis/emphysema Infectious disease Inhalation accidents Lung cancer Mesothelioma Benign pleural disease Pneumoconiosis Other All reports , , , 67, , 'Based on, cases for which sex was specified. "Based on,6 cases for which age or date of birth were specified. compared with,6 followed by mesothelioma in second place and benign pleural disease in third, reports of both of which were considerably increased since the previous year. The estimated total for mesothelioma, 978, was close to the most recent total of deaths for mesothelioma,,5 (including non-pleural cases). Pneumoconiosis was next in frequency followed by inhalation accidents. Mineral dust diseases taken together remained responsible for over half the new work-related illnesses seen by specialist physicians. In the 'Other' respiratory disease category, 9 cases were reported, 9 of which were of rhinitis, three of metal fume fever, one of diffuse interstitial pneumonitis and one of traumatic pneumothorax. There was no case reported in 997 of sick building syndrome or of byssinosis, which are included in this category. Byssinosis has not been reported to SWORD since early 99. 'Core' chest physicians are asked to classify new cases of asthma into those apparently related to sensitization and those which are apparently irritant-induced (RADS). This year 8% of cases were attributed to sensitization, % to irritants and 5% were not specified, (fairly similar to 7%, % and % reported in 996). Cases of benign pleural disease were similarly subdivided according to whether plaques or diffuse disease predominate. Seventy-three per cent were in the former category, 6% in the latter and % were unspecified (compared with 7%, 7% and % reported in 996). Incidence rates by industry SWORD now collects data both on the industry in which patients were employed and on the specific jobs they did. In previous years these were not reported separately and this presented difficulties in analysis. Table shows rates of occupational disease by industry, excluding diseases of long latency (i.e., malignancy, pneumoconiosis. other asbestos-related diseases and bronchitis/emphysema) for which current denominators might be misleading. Industries are shown in major groupings, with rates given for industries at high risk. The denominators were taken from the Labour Force Survey (LFS) of winter , which is based on sampling. Thus, where the denominator is less than 0,000, e.g., for salt mining, it might not be reliable; such industries are indicated in the table. The highest rates were generally seen in the manufacturing industries and mining. Among specific industries, employees in food production who dealt with grain or fish (chiefly crustaceans, in contrast to salmon and trout which predominated in previous years) had very high annual rates of occupational asthma (,85 and,56 per million workers respectively). The high figure for occupational asthma in coal miners, although based on only two cases in the sample, tends to support the high selfreported rates of asthma noted in the studies based on the LFS by Jones etal. Both our cases were attributed to coal dust; however, it may be relevant that in 99, seven cases of asthma were reported in miners exposed to roof bolting adhesives which included resin and hardening agents. 5 The high rates among detergent and soap manufacturers were ascribed about equally to proteolytic enzymes in detergents and solvents in perfume making. Among rubber workers, half the cases were associated with resins and half with rubber fume. Occupational asthma was also seen frequently among wood workers (excluding carpenters in the construction trade), textile workers (particularly weavers and finishers) and among workers with precious metals and in the non-ferrous metal industries (mostly aluminium and lead). The highest rates of inhalation accidents, most of which were reported by occupational physicians, occurred in the manufacture of chemical products (77/million/year), or 8/million/year, if cases of'acute upper Downloaded from on November 07

3 D. J. Ross et al.: SWORD '97 8 Table. Incidence of diseases of short latency by industry, 997 Industry (SIC Code 99') No. of cases Asthma Inhalation accidents Allergic alveolitis Infectious disease Other Total Rate/million/ year* Farming (0.) Mining/extraction (0-) Salt (.) Coal (0.) Chemicals and fertilizers (.) Food production (5) Grain products (5.6) Fish (5.) Textiles manufacture (7) Finishing (7.) Fibre production (7.) Weaving (7.) Manufacture of wood products (0) Sawmills, impregnation of wood (0.) Mfr. of builder's joinery (0.) Manufacture of chemical products () Making detergents and soaps (.5) Manufacture of rubber and plastic products (5) Rubber products (5.) Metal production (7) Precious and non-ferrous metals (7.) Other manufacture (6-7 excluding the above) Utilities and construction (0-5) Hotels, restaurants, sales, and transport (-6) Business, public administration and education (70-80) Health (85) Veterinary activities (85.) Human health (85.) Other (65-69, ) Not classified Overall , ,595 89,, C 5,85 C, ,07= 'Standard Industrial Classification 99, HMSO, London. b Rate calculated from Labour Force Survey (LFS) Data (winter 996). C LFS denominators less than 0,000 so may not be reliable. respiratory tract irritation' reported in the 'Other' category are included. Incidence rates were also high among health care workers (65/million/year): of cases (an estimated total of 0), six were due to halo thane, two to acetic acid in laundry staff, two to sterilizing agents used by nurses and one to sodium hydroxide in an ambulance man. The scale of this problem in the health sector has not been noted previously. The incidence of allergic alveolitis was high among veterinary staff and farmers, where it was attributed to mushrooms, hay and avian proteins. Infectious diseases were mainly reported in food processors (/million/year) and health care workers (7/million/year); among the former, the agents were Mycobacterium tuberculosis and Chlamydia psittaci, the latter among poultry workers. An analysis of occupationally acquired infectious disease based mainly on reports from consultants in communicable disease control (CCDCs) has been published separately. 6 In the 'Other' category, high rates of rhinitis were seen among research staff and chemical workers. Latex and occupational asthma Of,0 cases of occupational asthma, 6 resulted from exposure to latex, now the fourth most frequently incriminated asthmagen. In addition, there were cases of latex allergy and two of rhinitis attributed to latex in the 'Other' category. The number of reports of latex-induced asthma has risen steeply since 99 (see Figure ). 'Core' chest physicians reported cases first, followed by occupational physicians (since 99), and the remaining chest physicians (since 996), perhaps reflecting the spread of awareness. Incidence rates based on the four-year total, Downloaded from on November 07

4 8 Occup. Med. Vol. 8, 998 Figure. Annual reports to SWORD of occupational asthma attributed to latex (99-97). no SO H occupational chest (sample) LJ chest (core) nfiff '9 '9 '9 V '95 '96 '97 year from 99 to 997, are shown in Table. Nursing staff account for the greatest number of cases, but incidence rates were higher among laboratory technicians. All the cleaners reported were health service workers, and, as the denominator includes all cleaners, rates among hospital cleaners would have been considerably higher; similarly rates for dental staff are probably an under-estimate. Cases of the month Brief case descriptions of special interest are invited for publication with our monthly reports. Eight cases, summarized below, were published last year (this excludes months when a detailed quarterly analysis is produced). A clerk working for a pharmaceutical company developed occupational asthma; although she had no direct contact with laboratory animals, she was thought to have been exposed to allergens carried to her on paperwork from the laboratories. Other reports of asthma included a welder exposed to fumes from mild steel, a retired carpenter working with padouk, a hard wood imported from sub- Saharan Africa by mail order, and a dentist exposed to sodium dichloro-isocyanurate (a sterilizing agent). A security guard exposed to high concentrations of diesel exhaust fumes while trapped in his vehicle for over an hour subsequently developed asthma, apparently irritant-induced. Several patients with asbestos-related disease were described whose direct exposure to asbestos was revealed only by very careful questioning. Finally, bird fancier's lung was described in a voluntary worker in a bird sanctuary. COMMENT A major strength of SWORD, and indeed of eventually the six other clinically-based reporting schemes for Table. Occupations with highest rates of occupational asthma attributed to latex, Occupation Laboratory technicians Shoe makers/repairers Chiropodists Dental nurses and technicians Nursing staff and auxiliaries Biological scientists Cleaners (SOC 9") (00) (555) () (6, 6 ) (0,,60, 6,6) (0) (958) No." 7 5 Rate/million/year C "Standard Occupational Classification 9, HMSO, London. b Using sampling fraction. c Denominator includes medical technicians; rate may be much higher. occupational disease, is that their coverage of the UK is close to complete, although admittedly only at the level of specialist physicians. In this and other previous reports, 7 ' 8 we have thus been able to present incidence rates, using denominators from the Labour Force Survey for persons employed in specific occupational groups. These are appreciably more informative than numerators alone and show, for example, that laboratory technicians were probably at greaterriskfrom latex-related asthma than nursing staff, although the latter had more cases. Now that the level of reporting has remained fairly stable for some years, we can begin to examine trends in incidence over time and eventually perhaps by region. Thus it is disturbing that the incidence of occupational asthma due to most agents has shown little sign of decrease over this period with, indeed, a clear increase since 99 in cases attributed to latex. It is of considerable interest that the evidence from EPIDERM, 9 the sister scheme for dermatologists, has shown a closely parallel incidence pattern for latex-induced dermatitis, although at a much higher level. As the other reporting schemes develop, other comparisons of this kind may become useful. ACKNOWLEDGEMENTS The authors are grateful to all participating physicians, with special thanks to those who submitted Cases of the Month (A. Burge, P. S. Burge, A. Seaton, D. J. Hendrick, C. Selby and D. J. Jones) and to Magda Wheatley and Rhian Jenkins, the project secretaries. The SWORD surveillance scheme is supported in part by a grant from the Health and Safety Executive. REFERENCES. Health and Safety Commission. Health and Safety Statistics 995/96. London, UK: HSE Books Ross DJ, Keynes HL, McDonald JC. SWORD 96: Surveillance of work-related and occupational respiratory disease in the United Kingdom. Occup Med 997; 7: Labour Force Survey data available from: Office for National Statistics, Drummond Gate, London SWV QQ, UK. Downloaded from on November 07

5 D. J. Ross et al.: SWORD ' Jones JR, Hodgson JT, Clegg TA, Elliott RC. Self-Reported Work-Related Illness in 995. London, UK: HSE Books, Sallie BA, Ross DJ, Meredith SK, McDonald JC. SWORD '9. Surveillance of work-related and occupational respiratory disease in the UK. Occup Med 99; : Ross DJ, Cherry NM, McDonald JC. Occupationally acquired infectious disease in the United Kingdom: Communicable Disease and Public Health 998; : Meredith SK, McDonald JC. Work-related respiratory disease in the United Kingdom, A report on" the SWORD project. Occup Med 99; : Meredith SK. Reported incidence of occupational asthma in the UK, J Epid Comm Health 99; 7: 59^6. 9. Cherry N, Chen Y, Keynes H, McDonald JC. Trends in reported allergy to rubber and latex in clinically based surveillance schemes in the UK. British Occupational Hygiene Society Annual Meeting, London, 998 [Abstract]. Downloaded from on November 07