title: Overlap syndrome with Sjögren's syndrome and systemic sclerosis in a steel rolling mill worker: a case report.
abstract: BACKGROUND
  There are few reports about work-related factors associated with Sjögren's syndrome. We report a case of overlap syndrome with Sjögren's syndrome and systemic sclerosis.
  
  
  METHODS
  A 54-year-old man was admitted due to dyspnea on exertion. The results of physical examination and laboratory findings were compatible with Sjögren's syndrome with systemic sclerosis. The patient had no pre-existing autoimmune disease, and denied family history of autoimmune disease. The patient worked in the large-scale rolling department of a steel manufacturing company for 25 years. Hot rolling is a rolling process performed at between 1100 °C and 1200 °C, generating a high temperature and a large amount of fumes, involving jet-spraying of water throughout the process to remove the instantaneously generated oxide film and prevent the high generation of fumes. In this process, workers could be exposed to silica produced by thermal oxidation. Other potential toxic substances including nickel and manganese seemed to be less likely associated with the patient's clinical manifestations.
  
  
  CONCLUSIONS
  Occupational exposure to silica seemed to be associated with the patient's clinical manifestations of overlap syndrome with Sjögren's syndrome and systemic sclerosis. Although the underlying mechanism is still unclear, autoimmune disease including Sjögren's syndrome affects women more often than men and there was no family history of autoimmune disease. These suggested that there was an association between occupational silica exposure and the disease of the patient. Future research about the association between long-term low dose exposure to silica and the development of autoimmune diseases should be encouraged.
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Min-Kee
authors.initials: MK
authors.lastname: Yi
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Choi
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Sung-Woo
authors.initials: SW
authors.lastname: Han
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Seng-Ho
authors.initials: SH
authors.lastname: Song
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kyung
authors.affiliation: Department of Occupational & Environmental Medicine, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Sang-Hwan
authors.initials: SH
authors.lastname: Han
keywords: Overlap syndrome; Silica; Sjögren's syndrome; Systemic sclerosis