. Insulation workers in Belfast. 2. Morbidity in men still at work. Two hundred and fifty-two (93 Y.) of the insulation workers in Belfast were examined by chest x-ray, questionnaire, clinical examination, and tests of respiratory function. The frequency of chest x-ray abnormality, lung field or pleural, increased from 13 % in men who had worked for less than 10 years to 85 % in men who had worked for 30 or more years in the industry. Pleural calcification was found in 15 x-rays. There was evidence suggesting that some men had pleural fibrosis or calcification due to exposure to asbestos in childhood. Rales were present in 61 % and clubbing in 11 % of men with lung field abnormality, but these were not common when the x-rays showed only pleural abnormality. Where the lung fields were involved there was a restrictive defect with impairment in lung function most marked in the forced vital capacity and single breath carbon monoxide transfer factor, but where the pleura was involved without lung field involvement there was a tendency to impairment of ventilatory function with a normal transfer factor. Cigarette smoking was associated with a greater impairment of lung function than was x-ray abnormality.Asbestos insulation has been used for many years in the Belfast shipyards. Since the second world war it has also been used increasingly in the construction of large buildings such as factories and hospitals. All insulation of ships or buildings in Belfast is subcontracted to a number of firms which specialize in this work. The present survey was undertaken to assess the effect on health of exposure to asbestos in men currently working in the trade, and to obtain a record which will form a baseline for a follow-up of this group of men.
MethodsThe men were contacted from lists given by their trade union and their employers. Two hundred and seventy-two men were working as insulators (apprentices, trained insulators, and insulator's labourers) during the present investigation and results from 252 (93%) are available for analysis. These include the 50 men in the series reported in study 1 (Wallace and Langlands, 1971). There were 17 refusals and in three men the results were incomplete. Thirteen women were employed by one of the firms in making asbestos or fibreglass quilts (known as 'mattresses') for insulation work. The women were all seen but their results are not included in the main analysis.The clinical history was taken by one of the authors (M.S.), who is a social worker, using the M.R.C. long respiratory questionnaire with special emphasis on the industrial history (Medical Research Council, 1960). It was not possible to obtain any information about relative exposure to different types of asbestos or to assess the time each individual had spent working with asbestos as distinct from other material, such as fibreglass, used in insulation, but the men were asked whether they had ever done 'limpet spraying' of asbestos which exposes the operator to a high concentration of asbestos dust. A 217
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.