Objective: To evaluate the risk of donation-related adverse reactions, donation behavior, and contributions to the blood supply among donors aged 56-65 years following extension of the upper age limit for voluntary blood donation, and to provide real-world evidence for optimizing blood donation age policies in China. Methods: A multicenter retrospective cohort was established using blood donation databases from Hainan, Shenzhen, and Jiangxi. A total of 1 180 767 donors contributing 2 020 407 whole-blood and apheresis donations were included. Donations were classified by donor age at each donation into the 18-55-year and 56-65-year groups. Generalized estimating equation (GEE) models were used to compare the risks of overall, local, and systemic donation-related adverse reactions between the two age groups. Restricted cubic spline analysis was used to assess the continuous association between donor age and the risk of overall adverse reactions. Poisson GEE models were used to compare annual donation frequency, and donation participation and contributions to the blood supply among donors aged 56-65 years were evaluated. The study was approved by the Ethics Committee of the Institute of Blood Transfusion, Chinese Academy of Medical Sciences (No.2025012) and registered with the Chinese Clinical Trial Registry (ChiCTR2500114960). Results: A total of 1 960 711 donations were included in the 18-55-year group and 59 696 in the 56-65-year group. The overall donation-related adverse reaction rates were 3.890‰and 0.704‰, respectively. Multivariable GEE analysis showed that, compared with donors aged 18-55 years, those aged 56-65 years had lower risks of overall adverse reactions (adjusted OR=0.294, 95%CI: 0.217-0.398, P<0.001) and systemic adverse reactions (adjusted OR=0.163, 95%CI: 0.101-0.263, P<0.001), whereas no statistically significant difference was observed in the risk of local adverse reactions (adjusted OR=1.337, 95%CI: 0.487-3.670, P=0.573). Donor age was nonlinearly associated with the risk of overall adverse reactions (P overall<0.001, P nonlinear<0.001), with the risk generally decreasing with increasing age between 18 and 65 years. The mean annual donation frequency was higher among donors aged 56-65 years than among those aged 18-55 years (1.63 vs 1.24 donations per year; adjusted IRR=1.34, 95%CI: 1.30-1.39, P<0.001). During the study period, donors aged 56-65 years contributed 2.95% of all donations; their whole-blood donations and whole-blood collection volume accounted for 2.36% and 2.37% of the corresponding totals, respectively. Conclusion: Under current health screening and standardized donor management, donors aged 56-65 years did not show an increased risk of short-term donation-related adverse reactions and demonstrated a higher annual donation frequency, together with a measurable contribution to the blood supply. These findings support appropriately extending the upper age limit for voluntary blood donation under strict health screening to broaden the donor pool and supplement the blood supply.

Objective To observe characteristics of the activity in resting brain of asymptomatic reflux esophagitis (RE) patients,and explore the role of default network in the pathogenesis of asymptomatic RE.Methods Functional magnetic resonance imaging (fMRI) was performed to scan the brains of 15 asymptomatic RE patients,15 symptomatic RE patients and 15 healthy volunteers under no-mission-stimulation state.With fractional amplitude of low frequency fluctuation (fALFF),characteristics of the strengthened and weakened regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were compared and analyzed.SPM 5 was applied for data preprocessing.Single-sample t test was performed to observe the noticeable active regions of each group under resting state,and then double-sample t test was used to compare the characteristics of active regions of the entire brain between asymptomatic RE patients and symptomatic RE patients or healthy individuals.Results Under resting state,the active brain regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were similar.The activity of only small part of brain regions in visceral sensory processing relevant networks changed.There was no significant difference in the active regions of default network under resting state between asymptomatic RE patients and healthy individuals.Compared with symptomatic RE patients,fALEF decreased at right central sulcus cover,right superior temporal gyrus,right insula,right transverse temporal gyrus,right postcentral gyrus,superior temporal gyrus and temporal pole (X=50,Y=-6,Z=12,t=2.7874,P＜0.01).Conclusion The difference in characteristics of activity in default network under resting state may play an important role in the pathogenesis of asymptomatic RE.