A retrospective cohort analysis on the association between blood donation intervals and adverse reactions to blood donation in Shenzhen, China

[Objective] To statistically analyze the association between blood donation intervals and the incidence of adverse reactions to blood donation based on blood donor data from Shenzhen. [Methods] Basic data and records of adverse reactions to blood donation among voluntary whole blood donors in Shenzhen from January 2017 to June 2025 were extracted. A total of 795 404 whole blood donations were recorded, including 502 743 from males and 292 661 from females, with 1 088 and 751 cases of adverse reactions, respectively. Analyses were performed using R software, including restricted cubic spline (RCS), binary logistic regression, and generalized estimating equations (GEE) to evaluate the correlation between donation intervals and adverse reactions. [Results] A total of 1 839 cases of adverse reactions were recorded, accounting for 0.23% of the total donations. Both binary logistic regression analysis and the generalized estimating equations (GEE) model showed that there was no significant difference in the incidence of adverse reactions between male and female donors with an interval of ≥6 months compared to those with an interval of ≥3 months but<6 months. Furthermore, using the 3-5 month interval group as the reference, the analysis indicated that the incidence of adverse reactions significantly increased in males with a 9-12 month interval, while no statistically significant differences were observed across any of the female subgroups. [Conclusion] There was no significant correlation between adverse reactions to blood donation and the donation interval. Compared with a donation interval of ≥6 months, an interval of<6 months does not lead to an increase in the incidence of adverse reactions among male or female donors. The findings of this study may help enhance the willingness of blood donors to participate.