Knowledge Related to Blood Donation and Iron, and Willingness to Take Iron Supplements Among Blood Donors in Multiple Countries.

Willingness to take iron supplements was high across all three scenarios among blood donors.

• Willingness ranged from 80.6% to 84.2% across the three scenarios assessed.
• The three scenarios were: to continue donating, when advised by a donor physician, and general iron supplementation rejection.
• Survey included 5691 whole blood donors from 6 countries (Netherlands, USA, Japan, Finland, Sweden, Germany).
• High acceptance rates suggest that postdonation iron supplementation may be a feasible strategy for donor iron management.

Trust in the blood service was strongly associated with willingness to take iron supplements.

• Trust in the blood service had an odds ratio of 1.64 (P < .001) for willingness when supplements were required to continue donating.
• Similar effects of trust were observed across other scenarios.
• Associations were adjusted for sex, age, country, prior supplement use, and trust in the blood service.
• These findings suggest that trust-building approaches may be more promising than education-focused strategies.

Prior supplement use was strongly associated with willingness to take iron supplements.

• Prior supplement use had an odds ratio of 1.87 (P < .001) for willingness when supplements were required to continue donating.
• Similar effects of prior supplement use were observed across other scenarios.
• Prior supplement use was included as a covariate in logistic regression models.

Knowledge and confidence were not consistently associated with willingness to take iron supplements.

• Knowledge was assessed using 16 true-or-false statements on 4 blood donation-related topics.
• Confidence was assessed by asking if donors were 'certain' or 'guessing' about their answers.
• Most donors exhibited medium to high knowledge and under-confidence in that knowledge.
• Despite measuring knowledge across multiple topics, knowledge and confidence did not consistently predict supplement willingness across scenarios.

Willingness to take iron supplements varied across countries, with higher willingness in Nordic countries.

• Countries surveyed included the Netherlands, USA, Japan, Finland, Sweden, and Germany.
• Nordic countries (Finland and Sweden) showed higher willingness compared to other countries.
• Country was included as an adjustment variable in logistic regression analyses.
• Cross-sectional survey design was used to assess these country-level differences.

Frequent blood donation can deplete iron stores, increasing the risk of iron deficiency anemia.

• Postdonation iron supplements may help preserve donor health.
• Willingness to take supplements likely depends on donor knowledge and confidence, which motivated the study design.
• The study was designed as a cross-sectional survey to assess these relationships among active whole blood donors.