Objectives: A progressive decline in endothelium-dependent vasodilation (EDV) in the human forearm with age has previously been reported. The aim of this study was to evaluate the interplay between age, gender and metabolic factors on EDV in healthy subjects in a population-based study.
Setting: Tertiary university hospital.
Subjects and design: Thirty-six healthy men and 30 women, aged 20-69 years, underwent measurements of forearm blood flow (FBF) at rest and during local infusions of 2 and 4 microg min-1 of metacholine (evaluating EDV) and 5 and 10 microg min-1 of sodium nitroprusside (evaluating endothelium-independent vasodilation, EIDV) and during reactive hyperaemia by venous occlusion plethysmography.
Results: Age was inversely related to EDV (r = - 0.41, P < 0.05 in men; r = - 0.61, P < 0.01 in women) and maximal FBF during reactive hyperaemia in both men and women. EIDV was significantly related to age in an inverse way in women only. EDV was more pronounced in females than in males before menopause (48 +/- 3 SD years, 635 +/- 186 vs. 502 +/- 269% in males, P < 0.05), but similar in women and men thereafter (374 +/- 141 vs. 370 +/- 185% in men). The slope of the regression line for the relationship between age and EDV was flatter in premenopausal than in postmenopausal women (- 2.3 vs. - 6.4), whilst this slope was similar in younger and older men (- 5.5 vs. - 5.3). In multiple regression analysis, fasting blood glucose levels and the waist/hip ratio remained the only significant predictors of EDV in men (P < 0.01 for both), whilst age was the only significant independent predictor of EDV in women (P < 0.01).
Conclusion: The interplay between age and metabolic factors as determinants of endothelial function is different in healthy men and women.