SchIegel presented data on 61 cases of skeletal f1uorosis among workers of a Swiss aluminum factory. Of 350 cases ofìndustrial fluorosis reported in the world’s literature, approximately 20 occcured in the smelting area of the aluminum industry. For processing aluminum from clay, cryolite (NaAlF6) is used as a fluxing agent. It permits the electrolysis at approximately 1000?C.
Of the 61 cases, 16 were diagnosed as fluorosis stage 0 to 1, 18 as stage 1, 23 as stage 2, and 4 as stage 3. Their ages ranged between 45 and 75 with an average of 62, and the duration of their employment between 9 and 49 years with an average of 28, The content of fluoride in the air amounted to approximately 3 +/- 1 mg F/m3. Their major symptoms were arthritic changes in the joints, especially in the spine. In the evaluation of the cases, the length of exposure to fluoride,. the degree of the X-ray changes and the presence of excessive fluoride in bones were considered.
In at least 5 patients, the levels of fluoride in the bones decreased within 2 to 3 years following termination of exposure and the bone density lessened. However, the calcifications in the articular capsules, in ligaments and in attachments of tendons remained unchanged. In c:ontrast to non-industrial fluorosis, the author noted excess1ve involvement of the elbow joint which is presumably due to habitual use of the arms, particularly when the workers ”break the crusts” by means of wooden beams. The author also emphasizes the difficulty in differentiating spontaneous arthrosis from fluorotic arthritis and states that he is engaged in further studies.