Yuan S, et al. - In order to evaluate the correlations of iron homeostasis with the risk of gout, rheumatoid arthritis, and inflammatory bowel disease, researchers performed a two-sample Mendelian randomization study. Single-nucleotide polymorphisms for iron status were chosen at the genome-wide significance level from a large genome-wide association study of 48,972 European-descent people. The corresponding odds ratios were 0.79, 0.59, 0.84 and 1.28 for rheumatoid arthritis. Genetically high iron status was positively correlated with gout and inversely related to rheumatoid arthritis based on consistent findings for four iron biomarkers. A causal association between iron status and inflammatory bowel disease was confirmed by limited MR evidence.