Whilst previous studies found that MMP9 levels were significantly associated with increased bone resorption in osteoporosis [10], others identified MMP-9 as a strong independent predictor of atherosclerotic plaque instability in stable coronary heart disease patients, its level is directly associated with the size of the necrotic core of the coronary atherosclerotic plaque [46]. Here, MMP9 is linked to osteoporosis.