Smoking and obesity in systemic lupus erythematosus: a cross-sectional study

Background: Both smoking and obesity have been demonstrated as risk factors in several autoimmune diseases. Little is known about the relationship between systemic lupus erythematosus (SLE) and both smoking and obesity. Objectives: To investigate the association between SLE, tobacco consumption and body mass index (BMI). Materials and methods: Using data from the largest Health Maintenance Organization (HMO) in Israel, the Clalit Health Services, we searched for an association between SLE, smoking and obesity. Chi-square and t-test were used for univariate analysis, and a logistic regression model was used for multivariate analysis. Data available from Clalit Health Services database included age, sex, BMI, smoking status, socioeconomic status (SES) and diagnoses of chronic diseases. Results: The study included 5018 patients with SLE and 25 090 age- and sex-matched controls. In multivariate analysis, we found a significant association between smoking and SLE (OR = 1·91). Conversely, there was no association between BMI and SLE. Conclusion: In this study, we have shown that smoking is independently associated with SLE, whereas BMI scores were not.