Risk factors for developing systemic lupus erythematosus: a case-control study in southern Sweden.
OBJECTIVE: To explore the risk factors that have been suggested to be associated with the development of SLE. METHODS: A case-control study was performed and a questionnaire was developed to obtain the data. Consecutive female incident cases diagnosed between 1981 and 1999 in a defined geographical area in southern Sweden were included. Controls, matched for calendar year of birth, were selected r