Homocysteine levels are inversely associated with capillary density in men, not in premenopausal women.

Background: Homocysteine is an independent predictor of cardiovascular risk. The mechanisms underlying this link are not fully elucidated. Whereas the role of vascular dysfunction in conduit arteries is extensively studied, the role of the microcirculation in this relationship is largely unexplored. We assessed the relationship between homocysteine levels and microvascular structure and function in a healthy, population-based cohort. Materials and methods: We cross-sectionally studied 260 participants (aged 42 years, 47% men) of the Amsterdam Growth and Health Longitudinal Study. Nailfold videocapillaroscopy was used to assess capillary density at baseline, during venous occlusion and during peak reactive hyperaemia. The relationship between tertiles of homocysteine and microvascular outcomes was evaluated using linear regression analyses, with adjustment for BMI and blood pressure. Stratified analyses were performed for men and women. Results: In men, we observed a negative, nonlinear relationship between homocysteine and baseline capillary density, showing a lower capillary density in the highest tertile of homocysteine [adjusted B -8·65 capillaries/mm