Iron status and risk factors for iron depletion in a racially/ethnically diverse blood donor population

Testosterone supplementation increases red blood cell susceptibility to oxidative stress, decreases membrane deformability, and decreases survival after cold storage and transfusion

BACKGROUND

Blood collection from donors on testosterone therapy (TT) is restricted to red blood cell (RBC) concentrates to avoid patient exposure to supraphysiological testosterone (T). The objective of this study was to identify TT-related changes in RBC characteristics relevant to transfusion effectiveness in patients.

STUDY DESIGN

This was a two-part study with cohorts of patients and blood donors on TT. In part 1, we conducted longitudinal evaluation of RBCs collected before and at three time points after initiation of T. RBC assays included storage and oxidative hemolysis, membrane deformability (elongation index), and oximetry. In part 2, we evaluated the fate of transfused RBCs from TT donors in immunodeficient mice and by retrospective analyses of NIH's vein-to-vein databases.

RESULTS

TT increased oxidative hemolysis (1.45-fold change) and decreased RBC membrane deformability. Plasma free testosterone was positively correlated with oxidative hemolysis (r = .552) and negatively correlated with the elongation index (r = -.472). Stored and gamma-irradiated RBCs from TT donors had lower posttransfusion recovery in mice compared to controls (41.6 ± 12 vs. 55.3 ± 20.5%). Recipients of RBCs from male donors taking T had 25% lower hemoglobin increments compared to recipients of RBCs from non-TT male donors, and had increased incidence (OR, 1.80) of requiring additional RBC transfusions within 48 h of the index transfusion event.

CONCLUSIONS

TT is associated with altered RBC characteristics and transfusion effectiveness. These results suggest that clinical utilization of TT RBCs may be less effective in recipients who benefit from longer RBC survival, such as chronically transfused patients.

Validity of donor-reported iron supplementation practices obtained at the time of donation

BACKGROUND

Iron supplementation (IS) improves blood donors' iron stores and allows more frequent blood donation. Understanding the accuracy of self-reported IS is helpful for potential application of IS practices to donor eligibility or donation intervals.

METHODS

Successful whole blood and red cell apheresis donors completed a survey at donation on the use of select dietary supplements. Respondents reporting use of either iron pills (IP) or multivitamins (MV) were invited by email to complete a similar follow-up survey 6-8 weeks later and to provide the quantitative iron content of IS by referring the donor to the pill bottle label. Consistency between baseline and follow-up responses was assessed overall and by pill type and demographic variables.

RESULTS

Of 2444 donors answering the baseline survey, 40% (978) reported MV or IP at donation, 354 of whom completed the follow-up survey. A majority of survey respondents (56%-61%) reported taking iron across the two surveys, and 21%-24% took MV but were uncertain if their pills contained iron. Of 215 reporting IS at baseline, overall concordance at follow-up was 68% and was higher for donors who were female, ≥50-years old, and taking iron as an iron pill rather than in a multivitamin.

CONCLUSION

Consistency of donor responses may be insufficient for use in guiding donor eligibility. Referring donors to their pill bottles was unsuccessful in improving the high frequency of uncertain responses. Incorporating IS into donor eligibility determinations is a complex endeavor that will benefit from careful planning and from post-implementation monitoring.

Microdoses of Recombinant Human Erythropoietin Enhance Time Trial Performance in Trained Males and Females

PURPOSE

We investigated the effects of recombinant human erythropoietin (rHuEPO) administration on exercise endurance, maximal aerobic performance, and total hemoglobin mass (tHb). We hypothesized that frequent, small intravenous injections of epoetin β would increase time trial performance, peak oxygen uptake (V̇O 2peak ), and tHb in both males and females.

METHODS

We included 48 healthy, recreational to trained males ( n = 24, mean ± SD V̇O 2peak = 55 ± 5 mL O 2 ·kg -1 ⋅min -1 ) and females ( n = 24; V̇O 2peak of 46 ± 4 mL O 2 ·kg -1 ⋅min -1 ) in a counterbalanced, double-blind, randomized, placebo-controlled study design stratified by sex. Time trial performance, V̇O 2peak , and tHb were determined before and after intravenous injections of either rHuEPO (9 IU·kg bw -1 epoetin β) or saline (0.9% NaCl) three times weekly for 4 wk.

RESULTS

A time-treatment effect ( P < 0.05) existed for time trial performance. Within the rHuEPO group, mean power output increased by 4.1% ± 4.2% ( P < 0.001). Likewise, a time-treatment effect ( P < 0.001) existed for V̇O 2peak , where the rHuEPO group improved V̇O 2peak and peak aerobic power by 4.2% ± 6.1% ( P < 0.001) and 2.9% ± 4.0% ( P < 0.01), respectively. A time-treatment effect ( P < 0.001) existed for tHb, where the rHuEPO group increased tHb by 6.7% ± 3.4% ( P < 0.001). A main effect of "sex" alone was also evident ( P < 0.001), but no sex-specific interactions were found. No changes were observed in the placebo group for mean power output, V̇O 2peak , peak aerobic power, or tHb.

CONCLUSIONS

Microdoses with intravenous rHuEPO provide a sufficient erythropoietic stimuli to augment tHb and enhance aerobic-dominated performance in both trained males and females.

Eligibility Considerations for Female Whole Blood Donors: Hemoglobin Levels and Iron Status in a Nationally Representative Population

Blood collection from minority populations improves the transfusion support of patients with sickle cell disease and thalassemia, but efforts are challenged by high deferral rates for hemoglobin (Hb) eligibility thresholds. This study sought to evaluate hemoglobin and iron status of a representative US female population to assess the suitability of 12.0 g/dL as minimum hemoglobin. Data were extracted from the National Health and Nutrition Examination Surveys (NHANES), 1999-2010. A national sample designed to reflect potential female blood donors (weight ≥110 lbs, not pregnant, no infectious marker reactivity, and no blood donation in past year) aged 16 to 49 years was analyzed for Hb and serum ferritin (SF) measures by race/ethnicity (N = 6937). Mean Hb and SF and the prevalence of iron deficiency ([ID] SF<12 ng/mL and SF<26 ng/mL) and low Hb (<12.5 g/dL and <12.0 g/dL) were estimated. Multivariable modified Poisson regression compared the prevalence for ID or low Hb at each cutoff by race/ethnicity. Mean SF values were higher and ID prevalence was lower in Non-Hispanic (NH) White (SF = 45.3 ng/mL, SF<12 ng/mL = 8.2%) than NH Black (SF = 39.6 ng/mL, SF<12 ng/mL = 14.2%) and Hispanic (SF = 36.5 ng/mL, SF<12 ng/mL = 12.7%) females. Compared to NH White females (13.7 g/dL), mean Hb was lower in NH Black (12.6 g/dL) and Hispanic females (13.4 g/dL). The percentage with Hb<12.5 g/dL was >4 times greater in NH Black (39.1%) and >2 times greater in Hispanic females (16.5%) compared to NH White (8.6%). Within 0.5 g/dL incremental categories of Hb, NH Black had higher mean SF levels and lower prevalence of SF<12 ng/mL or <26 ng/mL compared to NH White and Hispanic females. At Hb of 12.0 to 12.4g/dL, NH Black females had better measures of iron status (SF = 39.1 ng/mL, %SF<12 ng/mL = 12.0%) than NH White (SF = 33.6 ng/mL, %SF<12 ng/mL=15.8%) and Hispanic (SF = 30.4 ng/mL, %SF<12 ng/mL=15.5%) females whose Hb was 12.5 to 12.9 g/dL. Adjusting for age and Hb, the prevalence ratio for low SF was significantly lower in NH Black compared to NH White females at both SF<26 ng/mL (adjusted prevalence ratio [aPR] = 0.83, 95%CI = 0.76-0.92) and SF<12 ng/mL (aPR = 0.66, 95%CI = 0.52-0.83). NH Black females with Hb 12.0 to 12.4g/dL have better iron stores than NH White and Hispanic females whose Hb is 12.5 to 12.9 g/dL. The distribution of Hb and iron may support the safe collection of blood for female donors below the current Hb eligibility requirement of 12.5 g/dL.

Iron status of blood donors

PURPOSE OF REVIEW

This review examines recent research on the prevalence and importance of iron deficiency in blood donors, and on efforts to mitigate it.

RECENT FINDINGS

Premenopausal females, teenagers, and high-frequency donors are at the highest risk for donation-induced iron deficiency, in both high-resource and low-resource settings. The physiology relating iron stores to hemoglobin levels and low hemoglobin deferral is well elucidated in blood donor populations, yet the clinical effects attributable to iron loss in the absence of anemia are challenging to identify. Expanded adoption of ferritin testing is improving donor management but may cause decreases in the blood supply from temporary donor loss. The potential for personalized donor management is emerging with development of computational models that predict individual interdonation intervals that aim to optimize blood collected from each donor while minimizing low hemoglobin deferrals.

SUMMARY

Measures to reduce iron deficiency are available that can be deployed on a standardized or, increasingly, personalized basis. Blood centers, regulators, and donors should continue to evaluate different tactics for addressing this problem, to obtain a balanced approach that is optimal for maintaining adequate collections while safeguarding donor health.

Lifestyle and dietary factors, iron status and one-carbon metabolism polymorphisms in a sample of Italian women and men attending a Transfusion Medicine Unit: a cross-sectional study

Iron (Fe) status among healthy male and female blood donors, aged 18–65 years, is estimated. General characteristics and lifestyle factors, dietary habits and major one-carbon metabolism-related polymorphisms were also investigated. An explorative cross-sectional study design was used to examine a sample of blood donors attending the Transfusion Medicine Unit of the Verona University Hospital, Italy. From April 2016 to May 2018, 499 subjects were enrolled (255 men, 244 women, 155 of whom of childbearing age). Major clinical characteristics including lifestyle, dietary habits and Fe status were analysed. The MTHFR 677C > T, cSHMT 1420C > T, DHFR 19bp ins/del and RFC1 80G > A polymorphisms were also assayed. Mean plasma concentrations of Fe and ferritin were 16·6 µmol/l (95 % CI 16·0, 17·2) and 33·8 µg/l (95 % CI 31·5, 36·2), respectively. Adequate plasma Fe concentrations (> 10·74 µmol/l) were detected in 84·3 % and adequate ferritin concentrations (20–200 µg/l) was found in 72·5 % of the whole cohort. Among the folate-related polymorphisms analysed, carriers of the DHFR 19bp del/del mutant allele showed lower ferritin concentration when compared with DHFR 19bp ins/del genotypes. In a sample of Italian healthy blood donors, adequate plasma concentrations of Fe and ferritin were reached in a large proportion of subjects. The relationship of Fe status with lifestyle factors and folate-related polymorphisms requires more investigation to clarify further gene–nutrient interactions between folate and Fe metabolism.

Individual and environmental determinants of serum ferritin levels: A structural equation model

BACKGROUND AND OBJECTIVES

Serum ferritin levels are increasingly being used to assess iron stores. Considerable variation in ferritin levels within and between individuals has been observed, but our current understanding of factors that explain this variation is far from complete. We aim to combine multiple potential determinants in an integrative model, and investigate their relative importance and potential interactions.

METHODS

We use ferritin measurements collected by Sanquin Blood Bank on both prospective (N = 59 596) and active blood donors (N = 78 318) to fit a structural equation model with three latent constructs (individual characteristics, donation history, and environmental factors). Parameters were estimated separately by sex and donor status.

RESULTS

The model explained 25% of ferritin variance in prospective donors, and 40% in active donors. Individual characteristics and donation history were the most important determinants of ferritin levels in active donors. The association between environmental factors and ferritin was smaller but still substantial; higher exposure to air pollution was associated with higher ferritin levels, and this association was considerably stronger for active blood donors than for prospective donors.

DISCUSSION

In active donors, individual characteristics explain 20% (17%) of ferritin variation, donation history explains 14% (25%) and environmental factors explain 5% (4%) for women (men). Our model presents known ferritin determinants in a broader perspective, allowing for comparison with other determinants as well as between new and active donors, or between men and women.

Ferritin Trajectories over Repeated Whole Blood Donations: Results from the FIND+ Study

Background: Depending on post-donation erythropoiesis, available iron stores, and iron absorption rates, optimal donation intervals may differ between donors. This project aims to define subpopulations of donors with different ferritin trajectories over repeated donations. Methods: Ferritin levels of 300 new whole blood donors were measured from stored (lookback) samples from each donation over two years in an observational cohort study. Latent classes of ferritin level trajectories were investigated separately using growth mixture models for male and female donors. General linear mixed models assessed associations of ferritin levels with subsequent iron deficiency and/or low hemoglobin. Results: Two groups of donors were identified using group-based trajectory modeling in both genders. Ferritin levels showed rather linear reductions among 42.9% of male donors and 87.7% of female donors. For the remaining groups of donors, steeper declines in ferritin levels were observed. Ferritin levels at baseline and the end of follow-up varied greatly between groups. Conclusions: Repeated ferritin measurements show depleting iron stores in all-new whole blood donors, the level at which mainly depends on baseline ferritin levels. Tailored, less intensive donation strategies might help to prevent low iron in donors, and could be supported with ferritin monitoring and/or iron supplementation.

The contribution and potential of older blood donors in Asia Pacific regions

OBJECTIVES

To investigate the blood supply contribution of older donors in five Asia Pacific regions.

BACKGROUND

Older people are often the largest blood user group. Thus, as the population ages blood supply needs increase. Minimum and maximum donation age criteria potentially constrain the size of the donor pool.

MATERIALS AND METHODS

Haemoglobin values and demographic frequency analytics (sex, age and blood type) were analysed on blood donors aged 60 years or more, from Hong Kong, Indonesia, Japan, Singapore and South Korea over 12 months.

RESULTS

Data on  434357 donations was analysed. ABO Rh(D) frequencies of older donors matched that of national frequencies. Older donors were a disproportionately smaller proportion of the total donor pool for each country. Indonesia was the only region with no maximum age limit. Median haemoglobin for older males ranged from 14.2 to 14.8 g/dl and for females 13.1 to 13.9 g/dl. The frequency of female donors was between 15% and 33% of older donors. Older donors had higher donation frequency and lower deferral rates.

CONCLUSION

Older donors are loyal and regular donors but under-represented in all regions studied. They could help meet future blood supply needs, especially post-menopausal female donors. Studies including ferritin levels are needed to determine if upper age limits can be safely modified.

Individualized risk trajectories for iron-related adverse outcomes in repeat blood donors

BACKGROUND

Despite a fingerstick hemoglobin requirement and 56-day minimum donation interval, repeat blood donation continues to cause and exacerbate iron deficiency.

STUDY DESIGN AND METHODS

Using data from the REDS-II Donor Iron Status Evaluation study, we developed multiclass prediction models to estimate the competing risk of hemoglobin deferral and collecting blood from a donor with sufficient hemoglobin but low or absent underlying iron stores. We compared models developed with and without two biomarkers not routinely measured in most blood centers: ferritin and soluble transferrin receptor. We generated and analyzed "individual risk trajectories": estimates of how each donors' risk developed as a function of the time interval until their next donation attempt.

RESULTS

With standard biomarkers, the top model had a multiclass area under the receiver operator characteristic curve (AUC) of 77.6% (95% CI [77.3%-77.8%]). With extra biomarkers, multiclass AUC increased to 82.8% (95% CI [82.5%-83.1%]). In the extra biomarkers model, ferritin was the single most important variable, followed by the donation interval. We identified three risk archetypes: "fast recoverers" (<10% risk of any adverse outcome on post-donation day 56), "slow recoverers" (>60% adverse outcome risk on day 56 that declines to <35% by day 250), and "chronic high-risk" (>85% risk of the adverse outcome on day 250).

DISCUSSION

A longer donation interval reduced the estimated risk of iron-related adverse outcomesfor most donors, but risk remained high for some. Tailoring safeguards to individual risk estimates could reduce blood collections from donors with low or absent iron stores.

Demographic, clinical, and biochemical predictors of pica in a large cohort of blood donors

BACKGROUND

Pica is characterized as repeatedly eating or chewing a non-nutritious substance including, but not limited to ice, clay and dirt, starch, raw pasta, chalk, coal, paint, or paper. Pica symptoms can be intense and addiction-like and disrupt quality of life. It is strongly linked to iron deficiency. Since substantial iron loss occurs during blood donation, blood donors may be susceptible to development of pica behaviors.

METHODS

We investigated demographic, clinical, hematological, and biochemical factors associated with pica using univariable and multivariable logistic regression analysis in a cohort of 11,418 racially diverse blood donors. Pica was defined by questionnaire responses as consuming at least 8 oz of ice daily and/or consumption of non-ice substances regardless of the amount and frequency.

RESULTS

Pica was present in 2.2% of the donors. The sensitivity and specificity of pica in iron-deficient donors were 36% and 82%, respectively. Lower ferritin (p = .001), non-Asian race (p < .001), higher red cell distribution width (p < .001), younger age, and restless legs syndrome (p = .008) were independently associated with pica. Female sex is associated with iron deficiency but was not an independent predictor of pica suggesting that iron deficient males and females were equally susceptible to the development of pica behaviors. Donors with normal ferritin levels also reported pica, reinforcing the role of non-iron related factors in its presentation.

CONCLUSIONS

We have identified demographic, clinical, and biochemical predictors of pica that help identify those most at risk for developing pica behaviors, and thereby assist in its clinical diagnosis and treatment.

Ethnic Differences in Iron Status

Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.

Iron deficiency among French whole-blood donors: first assessment and identification of predictive factors

BACKGROUND

The objectives of this study are to estimate the prevalence of iron deficiency (ID) among French whole-blood (WB) donors to identify factors associated with ID and to generate decision trees.

STUDY DESIGN AND METHODS

A prospective National multicentre study was performed on WB donors from March 11, to April 5th, 2019. Samples were selected randomly to perform serum ferritin. ID was defined as ferritin value under 26 ng/ml. All results were stratified by sex. Factors associated with ID were analysed using multivariate logistic regression model. CART algorithm was used for decision trees.

RESULTS

Eleven thousand two hundred fifty eight WB donors were included. ID was more frequent in women (39·5%) than in men (18·0%). Among 7200 repeated donors, women below 50 yo had a higher risk (OR = 2·37; [1·97-2·85] IC95) than those above 50 yo. Factors associated with ID were: haemoglobin level under the threshold at donation n-1 except for women and n-2 donation; a low mean corpuscular haemoglobin at n-1 and n-2 donations; a shorter interval since n-1 donation and between n-1 and n-2 donations except for women; and women who had given three or four times in the last year. CART algorithm defined high risk of ID subgroups within three populations of donors, new female donors, repeated male donors and repeated female donors. In these identified subgroups, prevalence of ID was up to 72·1%.

CONCLUSIONS

Our study showed the high prevalence of ID among French WB donors, identified well-known and new factors associated with ID and defined algorithms predicting ID in three populations.

The benefits of iron supplementation following blood donation vary with baseline iron status

Whole blood donation rapidly removes approximately 10% of a donor's blood volume and stimulates substantial changes in iron metabolism and erythropoiesis. We sought to identify donors who benefit from iron supplementation, describe the nature of the benefit, and define the time course for recovery from donation. Blood samples were collected over 24 weeks following whole blood donation from 193 participants, with 96 participants randomized to 37.5 mg daily oral iron. Changes in total body, red blood cell (RBC), and storage iron, hepcidin, erythropoietin, and reticulocyte count were modeled using semiparametric curves in a mixed model. and the changes were compared among six groups defined by baseline ferritin (<12; 12-50; ≥50 ng/mL) and iron supplementation. The effect of oral iron on storage and RBC iron recovery was minimal in donors with baseline ferritin ≥50 ng/mL, but sizeable when ferritin was <50 ng/mL. Iron initially absorbed went to RBC and storage iron pools when ferritin was <12 ng/mL but went mostly to RBCs when ferritin was ≥12 ng/mL. Donors with ferritin ≥12 ng/mL had a "ripple" increase in reticulocytes ~100 days after donation indicating physiological responses occur months following donation. Thus, iron supplements markedly enhance recovery from whole blood donation in donors with ferritin <50 ng/mL. However, full recovery from donation requires over 100 days when taking iron. The findings also highlight the value of the study of blood donors for understanding human hemoglobin and iron metabolism and their usefulness for future studies as additional biomarkers are discovered.

Genetic and behavioral modification of hemoglobin and iron status among first-time and high-intensity blood donors

BACKGROUND

Some people rapidly develop iron deficiency anemia following blood donation, while others can repeatedly donate without becoming anemic.

METHODS

Two cohorts of blood donors were studied. Participants (775) selected from a 2-year longitudinal study were classified into six analysis groups based on sex, donation intensity, and low hemoglobin deferral. Associations with iron supplement use, cigarette smoking, and four genetic variants of iron metabolism were examined at enrollment and with longitudinal regression models. An unbiased assessment of genetic variability and ability to repeatedly donate blood without experiencing low hemoglobin deferral was conducted on participants (13,403) in a cross-sectional study who were examined by genome wide association (GWA).

RESULTS

Behaviors and genetic variants were associated with differences in hemoglobin and ferritin change following repeated donation. At least weekly iron supplement use was associated with improved status in first-time donors, while daily use was associated with improved status in high-intensity donors. Cigarette smoking was associated with 0.5 g/dL increased hemoglobin in high-intensity donors. A736V in TMPRSS6 was associated with a rapid drop in hemoglobin and ferritin in first-time females following repeated donation. Conversely, the protective TMPRSS6 genotype was not enriched among high-intensity donors. H63D in HFE was associated with increased hemoglobin in female high-intensity donors. However, no differences in genotype between first-time and high-intensity donors were found in GWA analyses.

CONCLUSION

Behavioral and genetic modifiers contributed to first-time donor hemoglobin and iron status, while iron supplement use was more important than underlying genetics in high-intensity donors.

Prevalence, risk factors, and ferritin testing to mitigate iron depletion in male plateletpheresis donors

BACKGROUND

Most single-donor platelet (SDP) donors transition to plateletpheresis after prior red blood cell (RBC) donation. Recruitment may follow identification of a high platelet count, a marker associated with iron depletion (ID). SDP donors may have underrecognized risk for iron depletion.

STUDY DESIGN AND METHODS

To assess the prevalence of ID, we performed ferritin testing on male plateletpheresis donors with hemoglobin levels less than 13.5 g/dL. Multivariable logistic regression identified risk factors for low ferritin (LF; ferritin ≤26 ng/mL) and absent iron stores (AIS; ferritin <12 ng/mL). To assess the impact of notifying donors of LF results, we compared donation behavior of "Test" subjects before and after sending an LF notification letter to that of "Control" subjects before and after increasing the minimum hemoglobin for male donors. An electronic survey to Test donors inquired about iron supplementation practices.

RESULTS

Prevalence of LF was 50% and AIS was 23%, with increase in risk associated with more frequent SDP donation, both controlling for RBC donation and in donors with no recent RBC donations. Donation frequency after intervention declined less in 1272 Test donors (19%, from 13.9 to 11.2 annualized donations) than in 878 Control donors (49%, from 12.3 to 6.3 donations). Only 20% of Test donors reported taking supplemental iron when they received the LF letter; 64% of those not taking iron initiated iron supplementation following the letter.

CONCLUSIONS

Donors were responsive to notification of LF and attendant messaging on iron supplementation. Ferritin testing potentially benefits donor health and a stable platelet supply.