Background: Aging is considered to be the major risk factor for development of atherosclerosis and coronary artery disease (CAD). Endothelial dysfunction is a systemic disorder and a key variable in the pathogenesis and complications of atherosclerosis. Endothelial dysfunction is an early event in atherogenesis, however, the effect of aging on endothelial function in men and women is not well elucidated.
Methods: To explore the association between age and flow-mediated dilation (FMD), we prospectively assessed FMD in 618 consecutive health subjects without known CAD, 387 (63%) men, mean age 55±11 years, and mean body mass index (BMI) 28±4 kg/m2. Following overnight fasting and discontinuation of all medications for ≥ 12 hours, percent improvement in endothelium-dependent brachial artery FMD (%FMD) and endothelium-independent, nitroglycerin-mediated vasodilation (%NTG) were assessed using high resolution (15 MHz) linear array ultrasound.
Results: Both groups were comparable regarding CAD risk factors, BMI, lipid panel, heart rate, systolic and diastolic blood pressure, concomitant medications, %FMD and %NTG. Brachial artery diameter was significantly smaller in women compared to men (5.47±0.97 mm vs 5.76±0.99 mm, p<0.001). In addition men were younger (53±11 years vs 57±11 years, p<0.001), and had a greater 10-year Framingham risk compared to women (11.3%±7.1% vs 4.9%±4.8%, p<0.01). In both men and women, age-related rate of decline in %FMD (Figure) and %NTG occurred subsequently and significantly from 40 years of age. No significant difference in age-related decline was noticed in men compared to women (p=0.690).
Conclusion: Aging is associated with progressive loss of FMD and NTG in the systemic arteries of healthy men and women with no apparent CAD.
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