Genetic, Nutritional, Infectious Disease, and Hormonal Factors in the Etiology of Systemic Lupus Erythematosus
Social & Scientific Systemsconducted this NIEHS population-based case-control gene-environment study of environmental risk factors in the development and progression of systemic lupus erythematosus (SLE) among 621 men and women in 53 counties in eastern North and South Carolina, and subsequently followed participants through an additional round of interviewing and medical record collection to assess the progression of the disease. Special emphasis was placed on recruitment of the African-American population, who constituted 28 percent of the enrolled. Population-based cases diagnosed with SLE were identified through a comprehensive network of rheumatology clinics in hospitals, medical schools, and 45 private practices representing more than 70 physicians in eastern North and South Carolina from 1997 to 1999, coordinated by us.
Control subjects were randomly selected from North Carolina and South Carolina driver's license files and invited to participate. Work agreements were established with 50 walk-in care clinics throughout North and South Carolina, where 265 cases and 355 controls attended a 1-hour structured interview with a field interviewer and had blood samples drawn.We designed forms; collected blood samples; hired, trained, and supervised field staff; enrolled subjects; coordinated the referral network; abstracted medical records; and maintained subject contact through newsletters and tracing activities.
A telephone followup interview of the original cases and controls took place 4 years later to assess health and insurance status for all participants. Information on the progression of lupus, including disability and impact of the disease on hospitalization and work history, was collected. Physicians were asked to complete a standard form (SLICC) to ascertain disease progression and severity. To assess the validity of patient-administered and physician-administered lupus damage scales, participants were asked for permission to access case medical records for review.We coded and edited all data and prepared final data sets.