Occupational Risk Factors for the Development of Systemic Lupus Erythematosus

GLINDA S. COOPER, CHRISTINE G. PARKS, EDWARD L. TREADWELL, E. WILLIAM ST. CLAIR, GARY S. GILKESON, and MARY ANNE DOOLEY

ABSTRACT.

Objective. There have been few studies of occupational exposures and systemic lupus erythematosus (SLE). We examined the association between the risk of SLE and occupational exposures (mercury, solvents, and pesticides), specific jobs (ever worked in teaching, healthcare, and cosmetology), and working night or rotating shifts.

Methods. Patients with recently diagnosed SLE (n = 265) were recruited through 4 university based and 30 community based rheumatology practices in North Carolina and South Carolina, USA. Controls (n = 355) were identified through driver's license records and were frequency matched to patients by age, sex, and state. Data collection included an in-person interview with detailed farming and work histories.

Results. Associations were seen with self-reported occupational exposure to mercury (OR 3.6, 95% CI 1.3, 10.0), mixing pesticides for agricultural work (OR 7.4, 95% CI 1.4, 40.0), and among dental workers (OR 7.1, 95% CI 2.2, 23.4). Although these associations were fairly strong and statistically significant, the prevalence of these exposures was very low and thus these estimates are based on a small number of exposed cases and controls. Weaker associations were seen between SLE and shift work (OR 1.6, 95% CI 0.99, 2.7) and among healthcare workers with patient contact (OR 1.7, 95% CI 0.99, 2.9). There was no association of SLE with use of solvents or among teachers or cosmetologists.

Conclusion. This study reveals the potential contribution of occupational exposures to the development of SLE, and highlights some exposures and experiences that should be examined in other studies using more extensive exposure assessment techniques and in experimental studies of autoimmunity. (J Rheumatol 2004;31:1928-33)

Key Indexing Terms:

SYSTEMIC LUPUS ERYTHEMATOSUS
AUTOIMMUNE DISEASE
OCCUPATION
MERCURY
SOLVENTS
PESTICIDES

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From the Epidemiology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina; Division of Rheumatology, East Carolina University School of Medicine, Greenville, North Carolina; Division of Rheumatology, Duke University Medical Center, Durham, North Carolina; Medical Research Service, Ralph H. Johnson Veterans Administration Medical Center and the Medical University of South Carolina, Charleston, South Carolina; and the Division of Rheumatology, University of North Carolina, Chapel Hill, North Carolina, USA.

Supported by the Division of Intramural Research of the National Institute of Environmental Health Sciences and the National Center for Minority Health and Health Disparities of the National Institutes of Health.

G.S. Cooper, PhD, Investigator; C.G. Parks, PhD, Fellow, Investigator, National Institute of Environmental Health Sciences; E.L. Treadwell, MD, Professor, East Carolina University School of Medicine; E.W. St. Clair, MD, Professor of Medicine, Duke University Medical Center; G.S. Gilkeson, MD, Professor, Ralph H. Johnson Veterans Administration Medical Center and the Medical University of South Carolina; M.A. Dooley, MD, Associate Professor, University of North Carolina at Chapel Hill.

Address reprint requests to Dr. G.S. Cooper, Epidemiology Branch, A3-05, NIEHS, PO Box 12233, Durham, NC 27709. E-mail: cooper1@niehs.nih.gov.

Submitted August 29, 2003; revision accepted April 7, 2004.

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