MMP9 and Alzheimer disease: While there was no cross-sectional association between free MMP-9 levels and ADAS-cog scores at baseline in the overall sample, diagnosis-stratified analyses revealed a significant cross-sectional association between higher baseline free MMP-9 levels and higher baseline ADAS-cog scores (indicative of worse performance) (β=12.34; 95% CI, 3.02 to 21.65; p=0.011) in women with AD (Fig. 3C).