A Study on the Change of the Bone Density among Workers Exposed to Hydrofluoric Acid

Kim, Ji Yong; Lim, Hyun Sul; Cheong, Hoe Kyeong; Lee, Hyeon Kyeong; Kang, Heung Sik

Abstract

Hydrofluoric acid is one of the strongest irritating, corrosive and poisonous inorganic chemicals. The most significant chronic consequence of excessive fluoride exposure is the disorder of skeletal system and connective tissue. The first stage of osteofluorosis consists of an increase in the density of flatbone such as pelvic bone and vertebral bones, with coarseness and blurring of bone trabecular. Therefore we wanted to observe the change of the bone density among workers exposed to hydrofluoric acid. Questionnaires and radiological investigations were performed for 39 hydrofluoric acid manufacturing factory worker sexposed to hydrofluoric acid. And then authors checked urinary fluoride level by fluoride ion method. the radiographs were doubly read by two radiologists for reliability. The results were as follows; 1. There was a significant difference in urinary fluoride level (p<0.01), but not in age, in tenure(p>0.05) among workers by the job title. 2. By the two radiologists, eight cases were read as bone fluorosis. The prevalence rate of bone fluorosis was 20.5%. 3. There was not a significant difference in general characteristic such as age, tenure and in muculoskeletal signs and symptoms between the fluorosis group and the normal group. 4. However, a close relationship between the occurence of the change of bone density and the degree of fluorde exposure such as burn was found. The difficulties in diagnosing fluorosis result from the questionable sensitively of x-ray techniques and from the non-specific associated signs and symptoms. A quantitative method such as densitometry to assessosteosclerosis and bone structure alteration and a follow-up study are needed.