Medical aspects of the manufacture and use of Portland cement. A review of the literature

The published literature on the medical hazards of cement manufacture and use (not including the effects of asbestos cement) is principally concerned with effects on the respiratory system. A much smaller part is concerned with effects on the skin, and there are references to effects on hearing and the gastro-intestinal tract.Critical appraisal of the literature on medical effects on the respiratory system reveals important defects in the methodology of most published work, principally a lack of adequate control groups and failure to allow for the effects of age and smoking habits. National differences of medical terminology, regional differences in composition of cement and probable differences in dust concentrations between plants compound the difficulties of interpretation of results.Claimed effects of cement dust on the respiratory tract include rhinitis, abnormalities of the chest radiograph, abnormalities of lung function tests, symptoms such as chronic productive cough (chronic bronchitis), and frequent chest infections. Tentative conclusions which may be drawn from the literature are that exposure to cement dust is probably related to both rhinitis and an increase in chronic productive cough (though the effects of smoking habits have not been allowed for in most studies), but that cement is unlikely to cause a severe fibrotic pneumoconiosis (like silicosis). Reports of slight abnormalities of the chest radiograph in cement workers are sufficiently common to justify concern that exposure to cement dust may cause tissue changes in the lungs. It is not known whether these abnormalities are associated with abnormal lung function. Studies of lung function have generally been inadequately designed, and no definite effect of cement on lung function has been demonstrated.Cement dermatitis (eczema) is well recognised, but its prevalence in cement workers has not been studied. It is usually associated with sensitivity to hexavalent chromium salts, which probably play an important part in causation. Nevertheless cement dermatitis may occur without chrornate sensitivity, and the abrasive, alkaline nature of cement is probably also an important factor. Cement ulcers are an occasional complication of prolonged contact with wet cement.No evidence was found for an increased risk of cancer as a result of exposure to cement dust, nor of diseases of the gastrointestinal tract.Doubt remains whether cement dust causes chronic productive cough, abnormalities of the chest radiograph, or abnormalities of lung function tests, but these questions could be answered by a properly designed epidemiological study of current cement workers and workers who have left the industry, and comparison of symptoms, chest radiographic appearances and lung function measurements, with estimates of dust exposure, taking account of age and smoking habits.