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BACKGROUND: Blood donors report better health-related quality of life (HRQL) than non-donors. Likewise, donors reporting good health are less likely to stop donating and have a higher donation frequency. This is evidence of the healthy donor effect (HDE). This study is the first to investigate the impact of HRQL and depressive symptoms on subsequent donor career.STUDY DESIGN AND METHODS: Prospective cohort study includes 102,065 participants from the Danish Blood Donor Study applying the 12-item short-form health survey (SF-12) measuring a mental (MCS) and a physical component score (PCS) and the Major Depression Inventory (MDI). Poisson and Cox regression models were used to assess the effect of SF-12 and MDI scores on donation frequency and donor cessation. Higher MCS/PCS scores indicate good HRQL, while higher MDI score indicates higher experience of depressive symptoms.RESULTS: For both sexes, MCS was positively correlated with donation frequency for up to 5 years, and similarly for PCS among women. A negative correlation between MDI score and donation frequency in the year following assessment was observed only among men. No correlation was observed among women. An increase in both MCS and PCS was associated with a lower risk of donation cessation in both sexes, while an increase in MDI score was only associated with an increased risk of donation cessation in men.CONCLUSION: MCS, PCS, and MDI score affect donor career. Thus, adjusting for donation frequency may reduce HDE-bias in donor health research. However, because of the small effect sizes, other ways of quantifying HDE may be beneficial.

Background The two previous versions of the Scandinavian donations and transfusions (SCANDAT) databases, encompassing data on blood donors, blood components, transfusions, and transfused patients linked to national health registers in Sweden and Denmark up until 2012, have been used to study donor health, disease transmission, the role of donor characteristics, and more. Study Design and Methods Here we describe the creation of the Swedish portion of the third iteration of SCANDAT – SCANDAT3‐S – with follow‐up from 1968 to the end of 2017, resulting in up to 50 years of uninterrupted follow‐up for donors and recipients. The database now also includes non‐transfused non‐donors with a blood typing result, increased temporal resolution for transfusions, and linkages to laboratory and drug prescription data. Results After data cleaning, the database contained 23 579 863 donation records, 21 383 317 transfusion records, and 8 071 066 unique persons with valid identification. In total, the database offers 28 638 436 person‐years of follow‐up for donors, 13 582 350 person‐years of follow‐up for transfusion recipients, and 65 613 639 person‐years of follow‐up for non‐recipient non‐donors, with possibility for future extension. Additionally, the database includes 167 820 412 dispense records for prescribed drugs and 316,338,442 laboratory test results. Since the latest update in 2012, >99.9% of all donations were traceable to a donor with valid identification, and >97% of all transfusions to a recipient with valid identification. Conclusion With extended follow‐up and more clinical detail, the Swedish portion of the third and latest iteration of the SCANDAT database should allow for more comprehensive analysis of donation and transfusion‐related research questions.

Background The prevalence of iron depletion is high among premenopausal women who donate blood frequently. Studies in nondonor populations indicate that iron deficiency anemia is associated with an increased risk of low birth weight. This prompts concerns that iron deficiency induced by frequent blood donation might impair subsequent fetal development. Study design and methods The aim of this study was to assess whether prepregnancy donation intensity affects the birth weight of singletons born at term (gestational week 38 or later) to nulliparous female donors in Denmark. We identified 293,897 first live singleton births to Danish women between 1997 and 2012 with complete information on gestational age, birth weight, child sex, parental age, maternal smoking status during pregnancy, and parental education length and annual income. Linear regression analysis was applied, with birth weight as outcome, number of donations within the 3 years before pregnancy as the explanatory variable, and confounding variables as described. Results Birth weight among children of low-intensity donors (n = 22,120) was 12.6 g (95% confidence interval, 6.7-18.6) higher than nondonors (n = 268,253) after controlling for the above-mentioned factors. The higher birth weight among low-intensity donors can be explained by the healthy donor effect. In fully adjusted analyses, birth weight among children of high-intensity donors (n = 3,524) was 20.2 g (95% confidence interval, 5.1-35.3 g) lower compared with low-intensity donors. This reduced birth weight among high-intensity donors compared to low-intensity donors may reflect blood donation-induced iron deficiency. Conclusions Our results show that high prepregnancy donation intensity is inversely associated with birth weight of singletons born at term to nulliparous women.

BACKGROUND Concern of transfusion-transmitted bacterial infections has been the major hurdle to extend shelf life of platelet (PLT) concentrates. We aimed to investigate the association between storage time and risk of positive blood cultures at different times after transfusion. STUDY DESIGN AND METHODS We performed a nationwide cohort study among PLT transfusion recipients in Denmark between 2010 and 2012, as recorded in the Scandinavian Donations and Transfusions (SCANDAT2) database. Linking with a nationwide database on blood cultures (MiBa), we compared the incidence of a positive blood culture among recipients of PLTs stored 6 to 7 days (old) to those receiving fresh PLTs (1-5 days), using Poisson regression models. We considered cumulative exposures in windows of 1, 3, 5, and 7 days. RESULTS A total of 9776 patients received 66,101 PLT transfusions. The incidence rate ratio (IRR) of a positive blood culture the day after transfusion of at least one old PLT concentrate was 0.77 (95% confidence interval [CI], 0.54-1.09) compared to transfusion of fresh PLT concentrates. The incidence rate of a positive blood culture was lower the day after receiving one old compared to one fresh PLT concentrate (IRR, 0.57; 95% CI, 0.37-0.87). Three, 5, or 7 days after transfusion, storage time was not associated with the risk of a positive blood culture. CONCLUSION Storage of buffy coat-derived PLT concentrates in PAS-C up to 7 days seems safe regarding the risk of a positive blood culture. If anything, transfusion of a single old PLT concentrate may decrease this risk the following day.

BACKGROUND Low hemoglobin (Hb) is associated with poor general health and adverse outcomes in a wide range of diseases. However, a link between Hb levels and the risk of infection among healthy individuals has yet to be investigated. STUDY DESIGN AND METHODS Using data from the Scandinavian Donations and Transfusions database, 497,390 donors were followed after 5,458,499 donations in health registers. With 1,339,362 person-years of follow-up, Andersen-Gill Cox regression was used to study the association of Hb levels below deferral thresholds, very low Hb levels (in the lowest 0.1 percentile), and declining Hb levels with the risk of infection as measured by hospital or outpatient contact for infection and filling of prescription for antimicrobials, respectively, within 3 months of donation. Analyses were stratified by sex, menopausal status, and frequency of donation. RESULTS Hb levels below deferral thresholds were not associated with a risk of hospital contact for infection among premenopausal women (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.95-1.14), postmenopausal women (HR, 0.77; 95% CI, 0.54-1.11), or men (HR, 0.97; 95% CI, 0.81-1.16), nor was there any association with hospital contact for very low Hb levels or patterns of declining Hb levels. However, subthreshold Hb levels were associated with a reduced risk of antimicrobial prescriptions among premenopausal women (HR, 0.92; 95% CI, 0.91-0.93), postmenopausal women (HR, 0.93; 95% CI, 0.89-0.97), and men (HR, 0.91; 95% CI, 0.88-0.94). CONCLUSIONS Neither Hb levels below deferral thresholds nor very low or declining Hb levels were associated with an increased risk of infection. This is reassuring, because blood donation can lead to lower Hb levels.

BACKGROUND Citrate anticoagulation during apheresis induces transient alterations in calcium homeostasis. It is unknown whether the repeated, transient alterations in calcium homeostasis experienced by repeated apheresis donors affects bone turnover to increase fracture risk. Our aim was to investigate the risk of osteoporotic and nonosteoporotic fracture among voluntary, frequent apheresis donors. STUDY DESIGN AND METHODS All apheresis donors were identified from the Scandinavian Donations and Transfusions database (SCANDAT2), which includes information on over 1.6 million blood donors from Sweden and Denmark from the years 1968 and 1981, respectively. Only data from Sweden were used for these analyses. Information on fractures was obtained by linking SCANDAT2 to hospital registers. Poisson regression was used to compute incidence rate ratios of fractures in relation to the cumulative number of apheresis donations, both overall and in fixed time windows. RESULTS In total, 140,289 apheresis donors (67,970 women and 72,319 men) were identified from the SCANDAT2 database and were followed for up to 23 years. We observed no association between the frequency of apheresis donation and the risk of fracture either in the overall study period or during fixed-length time windows. The incidence rate ratio of fractures in donors who had made 100 or more cumulative apheresis donations was 0.99 (95% confidence interval, 0.92-1.06) compared with donors who had made from 9 to 24 donations. The results were similar in analyses stratified by sex and restricted to postmenopausal women. CONCLUSIONS The absence of an association between repeated apheresis donation and fracture risk indicates that apheresis collection is safe with regard to bone health.

BACKGROUND It has been suggested that blood donors could have an increased risk of polycythemia vera (PV). However, no study has assessed whether frequent donors have a higher PV risk than less frequent donors. STUDY DESIGN AND METHODS From the Scandinavian Donations and Transfusions (SCANDAT2) database, we established a cohort of blood donors who had donated whole blood at least once between 1980 and 2012. Within this cohort we first assessed the risk of PV, comparing the donors to the general population using standardized incidence ratios (SIRs) with corresponding 95% confidence intervals (CIs). To assess the association between frequency of blood donation and risk of PV we then conducted a case-control study nested within the cohort, where we compared prior donation activity among donors who were diagnosed with PV and matched controls. Here odds ratios (ORs) were used as measures of relative risk comparing donors with different donation frequency. RESULTS Among 1.4 million donors in the cohort a total of 271 donors developed PV, yielding a SIR of 1.00 (95% CI, 0.89-1.13) compared to the general population. The nested case-control study showed no association between donation frequency and risk of PV. The OR of PV comparing donors who had made at least 33 donations in the period from 3 to 22 years before diagnosis of the case, to donors with one to eight donations in the same period was 1.01 (95% CI, 0.51-1.97). CONCLUSIONS We find no evidence of excess risk of PV among blood donors or of an association between donation frequency and PV risk.

BACKGROUND Studies have repeatedly demonstrated that blood donors experience lower mortality than the general population. While this may suggest a beneficial effect of blood donation, it may also r ...

BACKGROUND Voluntary blood donation is believed to be mostly motivated by altruism. Because studies have suggested that altruistic personality is determined by both genetic and environmental factors, we speculated that willingness to donate blood could also be governed by constitutional factors. This hypothesis was tested in a study among Danish twins. STUDY DESIGN AND METHODS The nationwide Danish Twin Register, which is virtually complete for all twins born since 1968, was linked with Danish portion of the Scandinavian Donation and Transfusion (SCANDAT) Database, which includes information on all active Danish blood donors from 2002 to 2012, to establish blood donor status for Danish twins, who at age 17 years became eligible for donation in 2002 or later. Casewise concordance in monozygotic (MZ) and dizygotic (DZ) twins were presented and heritability was estimated in Mx by variance component analysis in a liability threshold model. RESULTS A total of 274 MZ and 484 same-sex DZ twins age 17 to 27 years were identified as donors in SCANDAT. There was no difference between MZ and DZ twins with regard to age at first donation or number of donations. Casewise concordance rates were 0.61 (95% confidence interval [CI], 0.56-0.67) and 0.41 (95% CI, 0.36-0.47) in MZ and DZ twin pairs, respectively. Heritability analysis using the ACE model found that additive genetic and shared environmental effects accounted for 0.53 (95% CI, 0.33-0.73) and 0.28 (95% CI, 0.10-0.45) of the variance in the motivation to donate blood, respectively. CONCLUSION Becoming a volunteer blood donor is determined by both genetic and environmental factors shared within families.

Background Risks of transfusion-transmitted disease are currently at a record low in the developed world. Still, available methods for blood surveillance might not be sufficient to detect transmission of diseases with unknown etiologies or with very long incubation periods. Study Design and Methods We have previously created the anonymized Scandinavian Donations and Transfusions (SCANDAT) database, containing data on blood donors, blood transfusions, and transfused patients, with complete follow-up of donors and patients for a range of health outcomes. Here we describe the re-creation of SCANDAT with updated, identifiable data. We collected computerized data on blood donations and transfusions from blood banks covering all of Sweden and Denmark. After data cleaning, two structurally identical databases were created and the entire database was linked with nationwide health outcomes registers to attain complete follow-up for up to 47 years regarding hospital care, cancer, and death. Results After removal of erroneous records, the database contained 25,523,334 donation records, 21,318,794 transfusion records, and 3,692,653 unique persons with valid identification, presently followed over 40 million person-years, with possibility for future extension. Data quality is generally high with 96% of all transfusions being traceable to their respective donation(s) and a very high (>97%) concordance with official statistics on annual number of blood donations and transfusions. Conclusions It is possible to create a binational, nationwide database with almost 50 years of follow-up of blood donors and transfused patients for a range of health outcomes. We aim to use this database for further studies of donor health, transfusion-associated risks, and transfusion-transmitted disease.

Concern of transfusion-transmitted bacterial infections has been the major hurdle to extend shelf life of platelet (PLT) concentrates. We aimed to investigate the association between storage time and risk of positive blood cultures at different times after transfusion.We performed a nationwide cohort study among PLT transfusion recipients in Denmark between 2010 and 2012, as recorded in the Scandinavian Donations and Transfusions (SCANDAT2) database. Linking with a nationwide database on blood cultures (MiBa), we compared the incidence of a positive blood culture among recipients of PLTs stored 6 to 7 days (old) to those receiving fresh PLTs (1-5 days), using Poisson regression models. We considered cumulative exposures in windows of 1, 3, 5, and 7 days.A total of 9776 patients received 66,101 PLT transfusions. The incidence rate ratio (IRR) of a positive blood culture the day after transfusion of at least one old PLT concentrate was 0.77 (95% confidence interval [CI], 0.54-1.09) compared to transfusion of fresh PLT concentrates. The incidence rate of a positive blood culture was lower the day after receiving one old compared to one fresh PLT concentrate (IRR, 0.57; 95% CI, 0.37-0.87). Three, 5, or 7 days after transfusion, storage time was not associated with the risk of a positive blood culture.Storage of buffy coat-derived PLT concentrates in PAS-C up to 7 days seems safe regarding the risk of a positive blood culture. If anything, transfusion of a single old PLT concentrate may decrease this risk the following day.

Background Dietary studies show a relationship between the intake of iron enhancers and inhibitors and iron stores in the general population. However, the impact of dietary factors on the iron stores of blood donors, whose iron status is affected by blood donations, is incompletely understood. Study Design and Methods In the Danish Blood Donor Study, we assessed the effect of blood donation frequency, physiologic factors, lifestyle and supplemental factors, and dietary factors on ferritin levels. We used multiple linear and logistic regression analyses stratified by sex and menopausal status. Results Among high-frequency donors (more than nine donations in the past 3 years), we found iron deficiency (ferritin below 15 ng/mL) in 9, 39, and 22% of men, premenopausal women, and postmenopausal women, respectively. The strongest predictors of iron deficiency were sex, menopausal status, the number of blood donations in a 3-year period, and the time since last donation. Other significant factors included weight, age, intensity of menstruation, iron tablets, vitamin pills, and consumption of meat and wine. Conclusion The study confirms iron deficiency as an important problem, especially among menstruating women donating frequently. The risk of iron depletion was largely explained by sex, menopausal status, and donation frequency. Other factors, including dietary and supplemental iron intake, had a much weaker effect on the risk of iron depletion.

Low hemoglobin (Hb) is associated with poor general health and adverse outcomes in a wide range of diseases. However, a link between Hb levels and the risk of infection among healthy individuals has yet to be investigated.Using data from the Scandinavian Donations and Transfusions database, 497,390 donors were followed after 5,458,499 donations in health registers. With 1,339,362 person-years of follow-up, Andersen-Gill Cox regression was used to study the association of Hb levels below deferral thresholds, very low Hb levels (in the lowest 0.1 percentile), and declining Hb levels with the risk of infection as measured by hospital or outpatient contact for infection and filling of prescription for antimicrobials, respectively, within 3 months of donation. Analyses were stratified by sex, menopausal status, and frequency of donation.Hb levels below deferral thresholds were not associated with a risk of hospital contact for infection among premenopausal women (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.95-1.14), postmenopausal women (HR, 0.77; 95% CI, 0.54-1.11), or men (HR, 0.97; 95% CI, 0.81-1.16), nor was there any association with hospital contact for very low Hb levels or patterns of declining Hb levels. However, subthreshold Hb levels were associated with a reduced risk of antimicrobial prescriptions among premenopausal women (HR, 0.92; 95% CI, 0.91-0.93), postmenopausal women (HR, 0.93; 95% CI, 0.89-0.97), and men (HR, 0.91; 95% CI, 0.88-0.94).Neither Hb levels below deferral thresholds nor very low or declining Hb levels were associated with an increased risk of infection. This is reassuring, because blood donation can lead to lower Hb levels.

Author(s): Edgren, Gustaf; Kamper-Jorgensen, Mads; Eloranta, Sandra; Rostgaard, Klaus; Custer, Brian; Ullum, Henrik; Murphy, Edward L; Busch, Michael P; Reilly, Marie; Melbye, Mads; Hjalgrim, Henrik; Nyren, Olof | Abstract: BackgroundDisquieting reports of increased complication and death rates after transfusions of red blood cells (RBCs) stored for more than 14 days prompted us to perform an observational retrospective cohort study of mortality in relation to storage time.Study design and methodsWe conducted a cohort study utilizing data on all recipients of at least one RBC transfusion in Sweden and Denmark between 1995 and 2002, as recorded in the Scandinavian Donations and Transfusions (SCANDAT) database. Relative risks of death in relation to storage time were estimated using Cox regression, adjusted for several possible confounding factors.ResultsAfter various exclusions, 404,959 transfusion episodes remained for analysis. The 7-day risk of death was similar in all exposure groups, but a tendency for a higher risk emerged among recipients of blood stored for 30 to 42 days (hazard ratio, 1.05; 95% confidence interval [CI], 0.97-1.12), compared to recipients of blood stored for 10 to 19 days. With 2-year follow-up, this excess remained at the same level (hazard ratio, 1.05; 95% CI, 1.02-1.08). No dose-response pattern was revealed and no differential effect was seen when the analyses were restricted to recipients of leukoreduced units only.ConclusionAlthough a small excess mortality was noted in recipients of the oldest RBCs, the risk pattern was more consistent with weak confounding than with an effect of the momentary exposure to stored RBCs. It seems, thus, that any excess mortality conferred by older RBCs in the combined Swedish and Danish transfusion recipient population is likely less than 5%, which is considerably smaller than in the hitherto largest investigation.

BACKGROUND: Transfusion safety rests heavily on the health of blood donors. Although they are perceived as being healthier than average, little is known about their long-term disease patterns and to which extent the blood banks' continuous efforts to optimize donor selection has resulted in improvements. Mortality and cancer incidence among blood donors in Sweden and Denmark was investigated. STUDY DESIGN AND METHODS: All computerized blood bank databases were compiled into one database, which was linked to national population and health data registers. With a retrospective cohort study design, 1,110,329 blood donors were followed for up to 35 years from first computer-registered blood donation to death, emigration, or December 31, 2002. Standardized mortality and incidence ratios expressed relative risk of death and cancer comparing blood donors to the general population. RESULTS: Blood donors had an overall mortality 30 percent lower (99% confidence interval [CI] 29%-31%) and cancer incidence 4 percent lower (99% CI 2%-5%) than the background population. Mortality rates and cancer incidence were lowest for outcomes that are recognized as being related to lifestyle factors such as smoking or to the selection criteria for blood donation. Blood donors recruited in more recent years exhibited a lower relative mortality than those who started earlier. CONCLUSION: Blood donors enjoy better than average health. Explicit and informal requirements for blood donation in Scandinavia, although mostly of a simple nature, have successfully refined the selection of a particularly healthy subpopulation Udgivelsesdato: 2007-Nov

It has been suggested that blood donors could have an increased risk of polycythemia vera (PV). However, no study has assessed whether frequent donors have a higher PV risk than less frequent donors.From the Scandinavian Donations and Transfusions (SCANDAT2) database, we established a cohort of blood donors who had donated whole blood at least once between 1980 and 2012. Within this cohort we first assessed the risk of PV, comparing the donors to the general population using standardized incidence ratios (SIRs) with corresponding 95% confidence intervals (CIs). To assess the association between frequency of blood donation and risk of PV we then conducted a case-control study nested within the cohort, where we compared prior donation activity among donors who were diagnosed with PV and matched controls. Here odds ratios (ORs) were used as measures of relative risk comparing donors with different donation frequency.Among 1.4 million donors in the cohort a total of 271 donors developed PV, yielding a SIR of 1.00 (95% CI, 0.89-1.13) compared to the general population. The nested case-control study showed no association between donation frequency and risk of PV. The OR of PV comparing donors who had made at least 33 donations in the period from 3 to 22 years before diagnosis of the case, to donors with one to eight donations in the same period was 1.01 (95% CI, 0.51-1.97).We find no evidence of excess risk of PV among blood donors or of an association between donation frequency and PV risk.

Studies have repeatedly demonstrated that blood donors experience lower mortality than the general population. While this may suggest a beneficial effect of blood donation, it may also reflect the selection of healthy persons into the donor population. To overcome this bias, we investigated the relation between blood donation frequency and mortality within a large cohort of blood donors. In addition, our analyses also took into consideration the effects of presumed health differences linked to donation behavior.Using the Scandinavian Donation and Transfusion database (SCANDAT), we assessed the association between annual number of donations in 5-year windows and donor mortality by means of Poisson regression analysis. The analyses included adjustment for demographic characteristics and for an internal healthy donor effect, estimated among elderly donors exempted from continued donation because of age criteria.Statistical analyses included 1,182,495 donors of whom 15,401 died during 9,526,627 person-years of follow-up. Analyses adjusted only for demographic characteristics showed a 18.6% reduction in mortality per additional annual donation (95% confidence interval [CI], 16.8%-20.4%). After additional adjustment for the internal healthy donor effect, each additional annual donation was associated with a 7.5% decreased mortality risk 7.5% (95% CI, 5.7%-9.4%).We observed an inverse relationship between donation frequency and mortality. The magnitude of the association was reduced after adjustment for an estimate of self-selection in the donor population. Our observations indicate that repeated blood donation is not associated with premature death, but cannot be interpreted as conclusive evidence of a beneficial health effect.

Voluntary blood donation is believed to be mostly motivated by altruism. Because studies have suggested that altruistic personality is determined by both genetic and environmental factors, we speculated that willingness to donate blood could also be governed by constitutional factors. This hypothesis was tested in a study among Danish twins.The nationwide Danish Twin Register, which is virtually complete for all twins born since 1968, was linked with Danish portion of the Scandinavian Donation and Transfusion (SCANDAT) Database, which includes information on all active Danish blood donors from 2002 to 2012, to establish blood donor status for Danish twins, who at age 17 years became eligible for donation in 2002 or later. Casewise concordance in monozygotic (MZ) and dizygotic (DZ) twins were presented and heritability was estimated in Mx by variance component analysis in a liability threshold model.A total of 274 MZ and 484 same-sex DZ twins age 17 to 27 years were identified as donors in SCANDAT. There was no difference between MZ and DZ twins with regard to age at first donation or number of donations. Casewise concordance rates were 0.61 (95% confidence interval [CI], 0.56-0.67) and 0.41 (95% CI, 0.36-0.47) in MZ and DZ twin pairs, respectively. Heritability analysis using the ACE model found that additive genetic and shared environmental effects accounted for 0.53 (95% CI, 0.33-0.73) and 0.28 (95% CI, 0.10-0.45) of the variance in the motivation to donate blood, respectively.Becoming a volunteer blood donor is determined by both genetic and environmental factors shared within families.

Risks of transfusion-transmitted disease are currently at a record low in the developed world. Still, available methods for blood surveillance might not be sufficient to detect transmission of diseases with unknown etiologies or with very long incubation periods.We have previously created the anonymized Scandinavian Donations and Transfusions (SCANDAT) database, containing data on blood donors, blood transfusions, and transfused patients, with complete follow-up of donors and patients for a range of health outcomes. Here we describe the re-creation of SCANDAT with updated, identifiable data. We collected computerized data on blood donations and transfusions from blood banks covering all of Sweden and Denmark. After data cleaning, two structurally identical databases were created and the entire database was linked with nationwide health outcomes registers to attain complete follow-up for up to 47 years regarding hospital care, cancer, and death.After removal of erroneous records, the database contained 25,523,334 donation records, 21,318,794 transfusion records, and 3,692,653 unique persons with valid identification, presently followed over 40 million person-years, with possibility for future extension. Data quality is generally high with 96% of all transfusions being traceable to their respective donation(s) and a very high (97%) concordance with official statistics on annual number of blood donations and transfusions.It is possible to create a binational, nationwide database with almost 50 years of follow-up of blood donors and transfused patients for a range of health outcomes. We aim to use this database for further studies of donor health, transfusion-associated risks, and transfusion-transmitted disease.

It is well known that blood donors are at increased risk of iron deficiency and subsequent development of iron deficiency anemia. We aimed to investigate the effect of factors influencing hemoglobin (Hb) levels.Initiated in 2010, the Danish Blood Donor Study is a population-based study and biobank. We performed multivariable linear regression analysis to assess the effects of donation activity, physiologic and lifestyle factors, and diet on Hb levels among 15,197 donors. We also performed multivariable logistic regression to evaluate the effects of these factors on the risk of having low Hb (defined as Hb below the 10th percentile among men and women, respectively) and of a decrease in Hb greater than 0.5 mmol/L (0.8 g/dL) between successive donations. All analyses were performed stratified for sex and smoking status. We also tested a previously used model for the prediction of Hb.The strongest predictors of Hb and risk of low Hb were low ferritin (15 ng/mL) and current use of iron supplementation (yes/no). No dietary factors were found to be consistently significant in multivariable models predicting Hb levels, risk of having low Hb, or risk of a decrease in Hb greater than 0.5 mmol/L. We found similar effects to previous studies of factors in the predictive model, with little additional effect of including smoking status and ferritin.As ferritin was the strongest predictor of Hb, this study supports the implementation of regular ferritin measurement as a method of risk assessment among blood donors.

Udgivelsesdato: 2010-Jan BACKGROUND: Various blood safety initiatives have ensured a historically low risk of infection transmission through blood transfusion. Although further prevention of infection transmission is possible through, for example, nucleic acid testing and future introduction of pathogen inactivation, such initiatives are very costly in relation to the benefit they offer. Although estimation of the cost-effectiveness requires detailed information about the survival of transfusion recipients, previous cost-effectiveness analyses have relied on incorrect survival assumptions. STUDY DESIGN AND METHODS: Based on empirical data of more than 1 million Scandinavian transfusion recipients followed for up to 20 years, we present two new survival functions. In a fictitious example we assessed the impact of survival assumptions on the estimated costs per quality-adjusted life-year (QALY) gained, by using the survival functions of three previous cost-effectiveness analyses along with the two new survival functions. CONCLUSIONS: We conclude that despite considerable costs, previous cost-effectiveness studies may have underestimated the costs per QALY gained by as much as 44%.

Disquieting reports of increased complication and death rates after transfusions of red blood cells (RBCs) stored for more than 14 days prompted us to perform an observational retrospective cohort study of mortality in relation to storage time.We conducted a cohort study utilizing data on all recipients of at least one RBC transfusion in Sweden and Denmark between 1995 and 2002, as recorded in the Scandinavian Donations and Transfusions (SCANDAT) database. Relative risks of death in relation to storage time were estimated using Cox regression, adjusted for several possible confounding factors.After various exclusions, 404,959 transfusion episodes remained for analysis. The 7-day risk of death was similar in all exposure groups, but a tendency for a higher risk emerged among recipients of blood stored for 30 to 42 days (hazard ratio, 1.05; 95% confidence interval [CI], 0.97-1.12), compared to recipients of blood stored for 10 to 19 days. With 2-year follow-up, this excess remained at the same level (hazard ratio, 1.05; 95% CI, 1.02-1.08). No dose-response pattern was revealed and no differential effect was seen when the analyses were restricted to recipients of leukoreduced units only.Although a small excess mortality was noted in recipients of the oldest RBCs, the risk pattern was more consistent with weak confounding than with an effect of the momentary exposure to stored RBCs. It seems, thus, that any excess mortality conferred by older RBCs in the combined Swedish and Danish transfusion recipient population is likely less than 5%, which is considerably smaller than in the hitherto largest investigation.

Udgivelsesdato: 2009-May BACKGROUND: Although essential for the evaluation of blood transfusion safety, the prevalence of blood transfusion in the general population is not presently known. This study estimated the exposure to blood transfusion in the general Scandinavian population. STUDY DESIGN AND METHODS: Population-based registry data of more than 600,000 transfusion recipients and general population data from 2000 to 2002 in Denmark and 1996 to 2002 in Sweden were reviewed. Outcome measures were the unit exposure rate, the 1-year period prevalence, the incidence rate, and the prevalence of exposure to blood transfusion. RESULTS: The unit exposure rate was 71.9 per 1000 population per year in Denmark and 60.9 in Sweden, corresponding to 29 percent more blood units being transfused in Denmark than in Sweden. The 1-year period prevalence was 8.8 and the incidence rate was 7.2 per 1000 population per year in Denmark, being 37 and 25 percent higher than in Sweden, respectively. The prevalences of blood transfusion in Danish males at 20, 40, 60, and 80 years of age were 1.9, 3.1, 7.6, and 18.1 percent, respectively. In Danish females, the corresponding prevalences were 1.6, 5.9, 11.1, and 20.5 percent. A similar but slightly lower prevalence was found in Sweden. CONCLUSION: Exposure to blood transfusion is frequent in Denmark and Sweden. At age 80 years, approximately one in five persons in the general population had received blood at least once.