Age and gender differences of endothelial function in 4739 healthy adults: the HUNT3 Fitness Study

Endothelial dysfunction is an important marker for prognosis in patients with coronary heart disease. However, there are no reference values for endothelial function in a healthy population. Our aim was to determine the distribution of flow-mediated dilation (FMD) values by gender and age in healthy adults.

FMD was measured by ultrasound during reactive hyperaemia in the brachial artery of 4739 adults aged 20-89 years, who were free from self-reported cardiovascular or pulmonary disease. Differences in FMD across age and gender were analysed by multiple linear regression.

Total mean ± SD FMD was 4.8 ± 4.2%, with corresponding estimates of 4.3 ± 3.9% for men and 5.3 ± 4.5% for women (p < 0.001). In total, 17% had FMD ≤0%, indicating endothelial dysfunction. FMD decreased with increasing age in both genders up to 70 years for men and 80 for women (p < 0.001). In women, age-related decline in FMD was steepest after age 45; in men, a steady decline after age 30. In men 80 years and older, FMD was higher than in men aged 50-79 years.

The distribution of FMD in this study is representative of the respective age and gender groups of a healthy population and may be a useful reference for future studies. The high proportion of endothelial dysfunction came as a surprise. Its age and gender distribution suggest that FMD ≤0% precedes cardiovascular disease and that it may be a powerful non-invasive biomarker for identifying high-risk individuals.