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Blood donation might improve vascular function. In this study, we aimed to search whether regular blood donation can improve flow mediated arterial vasodilation or not in healthy adult males.
50 consecutive adult male participants without overt cardiovascular disease, who did not donate blood within the last 6 months, were enrolled into the study. Patients with hypertension, diabetes mellitus, chronic inflammatory diseases were not included. Regular blood donation was defined as consecutive blood donation of more than two with intervals exceeding two months but less than three months. All participants accepted to donate blood to the blood bank of our hospital for at least three times with two-three months intervals. Flow mediated vasodilatation (FMD) was measured through the contralateral brachial artery before the initiation of regular blood donation, 1 month after each donation by an experienced author, blinded to study plan. Images were obtained at rest, during reactive hyperemia, induced by ischemia of forearm for 5 minutes. One year after the completion of the active phase of the study, all participants were contacted again, and were asked for continuation of blood donation habit. 21 participants stated that they stopped blood donation completely after the end of the study. These 21 participants were invited for a control visit including FMD evaluation again. All these 21 participants were still keeping similar attitudes at the time of control visit.Plus, hs-CRP was measured before, 3 days after and 1 month after the first blood donation (n=50), and also in participants who accepted the follow up visit (n=21).
Mean age of the participants was 29.7±5.6 years. 49 out of 50 were current smokers. Blood donation improved FMD steadily and significantly as compared to baseline (mean:10.25% vs 10.44% vs 10.66% vs 10.88%, p=0.039, p=0.003, p=0.001, Figure 1). Furthermore, percent improvement in FMD (with regard to donation state after the last donation and basal state) was negatively correlated with the FMD at baseline, i.e, those with lower FMD at baseline improved more after regular blood donation. After a mean follow up period of 18 months with regard to first blood donation (equal to 1 year after the last donation), mean FMD was found to deteriorate by time as compared to baseline in those who stopped blood donation (n=21, 10.2% vs 9.1, p=0.009). In accordance with this, hs-CRP steadily decreased as compared to baseline (mean:2.41 mg/L vs 2.03 mg/L vs 1.95 mg/L, p=0.154, p=0.085, Figure 2). Furthermore, after follow up, it was found to return to baseline level again (mean:2.44 mg/L).
It was shown that regular blood donation improves FMD in healthy adult males. On the other hand, discontinuation of blood donation seems to unshackle progressive decline of FMD.