Exploring the association between blood donation and anemia: A cross‑sectional study based on the NHANES

Blood donation is essential for maintaining an adequate blood supply, but repeated donation can lead to iron depletion and anemia. Evidence from nationally representative populations is limited.

We conducted a cross-sectional analysis of adults (≥18 years) from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. Blood donation within the past 12 months was self-reported. Outcomes included anemia (hemoglobin <13.0 g/dL in men, <12.0 g/dL in women), iron deficiency (serum ferritin <70 µg/L), and iron deficiency anemia (IDA, both conditions). Secondary outcomes included serum ferritin, serum iron, total iron-binding capacity (TIBC), and transferrin saturation. Multivariable logistic regression was used to estimate odds ratios (ORs) with 95 % confidence intervals (CIs), adjusting for sociodemographic, lifestyle, and clinical factors.

Among 16,619 adults, 738 (4.4 %) reported blood donation in the past year. Donors were younger, more often male, physically active, and had lower prevalence of hypertension and diabetes. Compared with non-donors, donors had significantly lower serum ferritin (98.8 vs. 160.2 µg/L), serum iron (78.3 vs. 84.5 µg/dL), and transferrin saturation (22.3 vs. 25.1), but higher total iron-binding capacity (360.4 vs. 345.2 µg/dL). Iron deficiency anemia was more common among donors (5.7 % vs. 1.3 %, p < 0.001). Donation was strongly associated with IDA (adjusted OR 3.72, 95 % CI 2.33-5.95, p < 0.001), but not with overall anemia.

Blood donation is independently associated with iron deficiency anemia but not with overall anemia in U.S. adults. Enhanced donor monitoring and preventive strategies may help safeguard donor health while maintaining blood supply.