Low ferritin levels appear to be associated with worsened health in male repeat blood donors.

BACKGROUND AND OBJECTIVES: Frequent blood donation depletes iron stores of blood donors. Iron depletion may lead to anaemia, but the health effects of iron depletion without anaemia in healthy blood donors are not well understood. We studied in the FinDonor cohort whether worsening of self-rated health of blood donors during the study period was associated with biomarkers for iron levels or other self-reported changes in lifestyle. MATERIALS AND METHODS: We included 1416 participants from the cohort who answered an 89-item questionnaire on their health and lifestyle during their enrolment visit and again at the end of the study. We performed multivariate logistic regression to test if blood donation-related factors affected the probability of reporting worsened health. To set these findings into a more holistic context of health, we subsequently analysed all other questionnaire items with a data-driven exploratory analysis. RESULTS: We found that donation frequency in men and post-menopausal women and ferritin level only in men was associated negatively with worsened health between questionnaires. In the exploratory analysis, stable physical condition was the only questionnaire item that was associated negatively with worsened health in both women and men. CONCLUSION: Our results suggest that low ferritin level is associated with worsened health even in non-anaemic repeat donors, although we find that when health is analysed more holistically, ferritin and other factors primarily related to blood donation lose their importance.

FinDonor 10 000 study: a cohort to identify iron depletion and factors affecting it in Finnish blood donors.

BACKGROUND AND OBJECTIVES: There is increasing evidence that frequent blood donation depletes the iron stores of some blood donors. The FinDonor 10 000 study was set up to study iron status and factors affecting iron stores in Finnish blood donors. In Finland, iron supplementation for at-risk groups has been in place since the 1980s. MATERIAL AND METHODS: A total of 2584 blood donors (N = 8003 samples) were recruited into the study alongside standard donation at three donation sites in the capital region of Finland between 5/2015 and 12/2017. All participants were asked to fill out a questionnaire about their health and lifestyle. Blood samples were collected from the sample pouch of whole blood collection set, kept in cool temperature and processed centrally. Whole blood count, CRP, ferritin and sTFR were measured from the samples, and DNA was isolated for GWAS studies. RESULTS: Participant demographics, albeit in general similar to the general blood donor population in Finland, indicated some bias towards older and more frequent donors. Participation in the study increased median donation frequency of the donors. Analysis of the effect of time lag from the sampling to the analysis and the time of day when sample was drawn revealed small but significant time-dependent changes. CONCLUSION: The FinDonor cohort now provides us with tools to identify potential donor groups at increased risk of iron deficiency and factors explaining this risk. The increase in donation frequency during the study suggests that scientific projects can be used to increase the commitment of blood donors.

The effect of donation activity dwarfs the effect of lifestyle, diet and targeted iron supplementation on blood donor iron stores.

The iron status of blood donors is a subject of concern for blood establishments. The Finnish Red Cross Blood Service addresses iron loss in blood donors by proposing systematic iron supplementation for demographic at-risk donor groups. We measured blood count, ferritin and soluble transferrin receptor (sTfR) and acquired lifestyle and health information from 2200 blood donors of the FinDonor 10000 cohort. We used modern data analysis methods to estimate iron status and factors affecting it with a special focus on the effects of the blood service's iron supplementation policy. Low ferritin (< 15 µg/L), an indicator of low iron stores, was present in 20.6% of pre-menopausal women, 10.6% of post-menopausal women and 6% of men. Anemia co-occurred with iron deficiency more frequently in pre-menopausal women (21 out of 25 cases) than in men (3/6) or post-menopausal women (1/2). In multivariable regression analyses, lifestyle, dietary, and blood donation factors explained up to 38% of the variance in ferritin levels but only ~10% of the variance in sTfR levels. Days since previous donation were positively associated with ferritin levels in all groups while the number of donations during the past 2 years was negatively associated with ferritin levels in pre-menopausal women and men. FRCBS-provided iron supplementation was negatively associated with ferritin levels in men only. Relative importance analyses showed that donation activity accounted for most of the explained variance in ferritin levels while iron supplementation explained less than 1%. Variation in ferritin levels was not significantly associated with variation in self-reported health. Donation activity was the most important factor affecting blood donor iron levels, far ahead of e.g. red-meat consumption or iron supplementation. Importantly, self-reported health of donors with lower iron stores was not lower than self-reported health of donors with higher iron stores.