Association Between Obesity and Sarcoidosis: A Systematic Review and Meta-analysis

Background: Sarcoidosis is a systemic inflammatory disease characterized by epithelioid granuloma formation in various organs. The etiology of sarcoidosis is unknown. Several studies report an increased risk of sarcoidosis in obese patients. The purpose of this study is to conduct a systematic review to assess the risk of sarcoidosis in obese or overweight patients, and to provide a population-based estimate of the risk of sarcoidosis in obese and overweight individuals. Methods: Using the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA) guidelines, we conducted a comprehensive search of studies (Randomized control trial (RCT), cohort or case-control) studies that estimated the risk of sarcoidosis with body mass index (BMI) between 2009-2019 using keywords and MESH terms related to obesity and sarcoidosis. The search was conducted in MEDLINE, EBSCO, and CINAHL. Three independent investigators reviewed each article and assessed for bias. Data was extracted from each study that met inclusion criteria. Quantitative analysis was performed using Review Manager 5.3 software. Results: An initial search yielded 77 potential articles; 73 articles did not meet inclusion criteria and 4 were included in the final analysis. The pooled risk estimate for the incidence of sarcoidosis in obese and overweight individuals was 1.68 [95% confidence interval 1.5-1.87] with a significant statistical heterogeneity, I2 of 92%. Conclusion: From our systematic review, obese and overweight individuals have a 68% (RR 1.68, 95% CI 1.50 to 1.87) increased risk of developing sarcoidosis in comparison with normal or underweight individuals. More studies are needed to further evaluate the role of obesity in the etiopathogenesis of sarcoidosis.