Prevalence of connective tissue disease in silicosis (1985-2006)-a report from the state of Michigan surveillance system for silicosis.
BACKGROUND
The risk of developing clinical connective tissue disease (CTD) has been reported to be increased among individuals with silica exposure.


METHODS
We reviewed the medical records of individuals reported to the Michigan Silicosis Surveillance system from 1985 to 2006 to confirm the diagnosis of silicosis and determine the presence of CTDs.


RESULTS
From 1985 to 2006, 1,022 cases were confirmed to have silicosis. Medical records of 790 cases were available. Thirty-three individuals had rheumatoid arthritis (RA) [prevalence 4.2% (prevalence ratio (RR) ranged from 2.26, 95% CI: 1.57-3.25 to 6.96, 95% CI: 2.93-16.53) depending on the reference rate used], two had scleroderma [prevalence 0.3% (RR 28.3, 95% CI: 6.09-129.98)], one had systemic lupus erythematosus [prevalence 0.1% (RR 2.53, 95% CI: 0.30-21.64)], two had Sjogrens syndrome [prevalence 0.3% (RR 0.42, 95% CI: 0.09-2.08)], and six had anti-neutrophil cytoplasm antibody (ANCA) vasculitis [prevalence 0.8% (RR 25.3, 95% CI: 6.34-101.04)]. There was no difference between those with and without CTD with respect to age, race, industry type, history of tuberculosis, application for workers' compensation, or severity of fibrotic changes on chest X-ray.


CONCLUSIONS
A two- to eightfold risk for RA and systemic lupus erythematosus, with a greater than 24-fold risk for scleroderma and ANCA vasculitis was found in individuals with silicosis. The most common CTD among silicotics in the Michigan disease registry was RA. Though not classically included in the category of CTD, ANCA-associated vasculitis was found to have a much greater prevalence amongst silicosis patients than the general population.
Department of Medicine, Michigan State University, East Lansing, USA.
Ashima
A
Makol
Mary Jo
MJ
Reilly
Kenneth D
KD
Rosenman
D000328:Adult; D017677:Age Distribution; D000368:Aged; D015897:Comorbidity; D016001:Confidence Intervals; D003240:Connective Tissue Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D016272:Occupational Health; D016017:Odds Ratio; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D012829:Silicosis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D014942:Workers' Compensation / Q000706:statistics & numerical data