S100A9 and endometriosis: For example, the association between S100A9 levels and endometriosis risk was OR = 1.52 (95%CI = 1.19–1.94) in the overall analysis but the magnitude of association increased to OR = 2.42 (95%CI = 1.17–4.98) when examining those who had blood collected proximal to endometriosis diagnosis.