Aluminium therapy in the prevention and treatment of silicosis: used for over 30 years in Canada but generally rejected elsewhere.

Thomas H

Background: It is hard to conceive the burden of occupational lung disease, particularly silicosis among miners that existed 60 years ago. Any possible preventative or treatment measures were eagerly considered by occupational health and chest physicians worldwide. In 1943 W D Robson, Medical Director of McIntyre Research Limited, Schumacher, Ontario advised miners that "Aluminium powder breathed into your lungs, combined with good ventilation and proper attention to water sprays, etc., below ground will protect you from developing the disease 'Silicosis.'" This potential breakthrough was considered almost immediately in at least 8 other countries. It was judged of such importance that, even in wartime Britain, the Medical Research Council (MRC) established a sub-committee to review aluminum therapy.

Objectives: To review the contemporary assessment of aluminium therapy by physicians outside Canada and briefly describe some of the uncontrolled trials which found benefit and an early British clinical trial that found no benefit.

Methods: The contemporary international papers (1940-1958) reviewed were found in box folders at Llandough hospital, S Wales by HT in 1998. They were in rooms previously used by the MRC Pneumoconiosis Unit which had closed a decade earlier.

Results: The British Trial (originally planned in 1947 and published in 1956) did not show benefits from aluminium therapy and the MRC sub-committee did not therefore recommend its use. Elsewhere it is probable that in total several thousand workers in silica exposed industries received aluminium "treatment." In Canada between 1944 and 1979 at least 10,000 miners received prophylactic therapy in the form of fine aluminium dust (20,000 - 34,000 parts per ml air) pumped into changing rooms for 10 min. before each shift. These men are now under surveillance for adverse health effects including dementia.

Conclusion: With major health problems potentially beneficial preventive and treatment measures may come into use without full evaluation. Claims of their benefits should be cautious and their use, if implemented before proper clinical trials, should be reviewed as evidence of benefit, no benefit or harm becomes available.

References: 1. Silicosis - what it is and how it can be prevented. W D Robson. McIntyre Porcupine Mines Limited. Canada 1943 2. Kennedy M C S. Study of aluminium therapy. British Journal of Industrial Medicine 1956;13:85-88 3. Rifat SL, Eastwood MR, Crapper McLachlan DR, Corey PN. Effect of exposure of miners to aluminium powder. Lancet 1990;336:1162-1165