Blood group associations with transfusion transmitted infections among Turkish blood donors: a retrospective 7-year review (2015-2021)

Background This study assessed associations between transfusion-transmitted infections (TTIs: hepatitis B, hepatitis C, HIV, syphilis) and demographic factors (sex, age, education) including ABO/Rh blood groups among Turkish blood donors from 2015 to 2021. Methods A retrospective cross-sectional analysis was performed on 56,766 donors confirmed with any TTI and permanently deferred from donation. The control group comprised 7,229,867 volunteer donors from the same period. Multivariable logistic regression analysis was conducted to assess independent associations between demographic factors and ABO/Rh blood groups with individual TTI risks, adjusting for potential confounders. False Discovery Rate correction was applied for multiple comparisons. Results Overall TTI prevalence was 0.779%, with HBV being most prevalent (0.594%), followed by syphilis (0.133%), HCV (0.031%), and HIV (0.024%). TTI prevalence decreased significantly over the study period. Male donors showed higher adjusted risk for all TTIs. Lower education levels (≤ 8 years) were associated with increased risk for all infections. Younger donors (18–34 years) had lower prevalence of HBV and syphilis compared to those ≥ 35 years. After FDR correction, several blood group associations remained significant: Blood group B Rh(+) showed increased risk for both HBV (aOR = 1.059, 95% CI: 1.032–1.088) and syphilis (aOR = 1.121, 95% CI: 1.062–1.184). AB Rh(+) donors had increased syphilis risk (aOR = 1.118, 95% CI: 1.035–1.206). Conversely, O Rh(+) showed protective association with syphilis (aOR = 0.855, 95% CI: 0.817–0.895), while A Rh(-) demonstrated protection against HBV (aOR = 0.935, 95% CI: 0.894–0.978). No significant associations were found between blood groups and HCV or HIV infections. Conclusion This large-scale study demonstrates declining TTI prevalence in Turkish blood donors and identifies demographic risk factors including male sex, older age, and lower education. ABO/Rh blood groups show statistically significant but modest associations with specific TTIs, particularly HBV and syphilis. These findings suggest blood group systems may represent non-modifiable risk factors through complex immunological mechanisms. Comprehensive molecular and genetic studies are needed to elucidate underlying mechanisms and validate these population-specific associations.