Notably, a number of cross-sectional studies have demonstrated an association between circulating MMP-9 levels and CHD risk factors before onset of disease e.g. hypertension [15, 16], smoking [17, 18], alcohol [18, 19], low physical activity [18], low intake of fruit and vegetables [18] and psychosocial risk factors [20]. Here, MMP9 is linked to coronary artery disorder.