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Objective: To investigate the risk of recurrent maternal red‐cell transfusion in delivery. Design: Nationwide long‐standing retrospective cohort study. Setting: Swedish medical birth register. Population: All registered births from 2000 to 2017 in Sweden. Methods: We included all women with between one and three consecutive registered births from 22 weeks of gestation onwards and all maternal red‐cell transfusions in the peripartum period within the defined period of study. Information on gestational and non‐gestational comorbidity was collected and we identified any female siblings. In our analyses we compared the risk of red‐cell transfusion in delivery in relation to transfusion history and gestational and non‐gestational comorbidity. Main outcome measures: Maternal peripartum red‐cell transfusion, defined as a recorded transfusion in the period from 1 day before and 7 days after delivery. Results: We included 825 451 women with a total 1 419 909 deliveries, including 786 097 (55.4%) first, 511 398 (36.0%) second and 122 414 (8.6%) third deliveries. Of women with previous obestric transfusion, 8.7% were transfused in a second delivery, compared with 1.7% of women without transfusion or diagnosis of haemorrhage. A previous diagnosis of haemorrhage did not affect the odds ratio of transfusion recurrence. Among women who were transfused in their first two deliveries, 15.5% were transfused in third delivery, corresponding to an 11‐fold increase, compared with non‐transfused women (adjusted odds ratio aOR 11.5, 95% CI 7.9–16.6). Women with a sister transfused in delivery were at increased risk of transfusion in a second delivery (aOR 1.8, 95% CI 1.6–2.1). Conclusions: Women with previous red‐cell transfusion are at an increased risk of red‐cell transfusion in a subsequent delivery, compared with women without a history of red‐cell transfusion. [ABSTRACT FROM AUTHOR]

Importance: Evidence regarding associations of blood donor sex with mortality among red blood cell transfusion recipients is conflicting.Objective: To study associations of donor sex and prior pregnancy with mortality of transfusion recipients.Design, Setting, and Participants: Data from 3 retrospective cohorts of transfusion recipients (the Kaiser Permanente Northern California [KPNC] and Recipient Epidemiology and Donor Evaluation Study-III [REDS-III] databases of data from January 2013 to December 2016 and the Scandinavian Donations and Transfusions [SCANDAT] database with data from January 2003 to December 2012) were analyzed. Final dates of follow-up were December 31, 2016, for the KPNC and REDS-III cohorts and December 31, 2012, for the SCANDAT cohort. Stratified Cox regression models were used to estimate associations between donor exposure groups with risk of mortality, adjusting for the number of red blood cell unit transfusions.Exposures: The number of transfused red blood cell units from female donors, previously pregnant donors, and sex-discordant donors (male donor and female recipient or female donor and male recipient).Main Outcomes and Measures: In-hospital mortality.Results: The study population included 34 662 patients (mean age, 69 years; 18 652 [54%] women) from the KPNC cohort, 93 724 patients (mean age, 61 years; 48 348 [52%] women) from the REDS-III cohort, and 918 996 patients (mean age, 72 years; 522 239 [57%] women) from the SCANDAT cohort. The median number of red blood cell transfusions per patient was 3 in the KPNC cohort, 2 in the REDS-III cohort, and 3 in the SCANDAT cohort. The percentage of transfusions from previously pregnant or parous donors was 9% in the KPNC cohort, 18% in the REDS-III cohort, and 25% in the SCANDAT cohort. The percentage of transfusions in the 3 cohorts from female donors ranged from 39% to 43%, from previously pregnant or parous donors ranged from 9% to 25%, and from sex-discordant donors ranged from 44% to 50%. There were 3217 in-hospital deaths in the KPNC cohort, 8519 in the REDS-III cohort, and 198 537 in the SCANDAT cohort. There were no statistically significant associations between any of the 3 donor exposures and in-hospital mortality in the 3 cohorts. Hazard ratios for in-hospital mortality per transfused unit from female donors were 0.99 (95% CI, 0.96-1.03) for the KPNC cohort, 1.00 (95% CI, 0.99-1.01) for the REDS-III cohort, and 1.00 (95% CI, 0.99-1.00) for the SCANDAT cohort. For units from previously pregnant or parous female donors, hazard ratios were 1.00 (95% CI, 1.00-1.01) for the KPNC cohort, 1.01 (95% CI, 0.98-1.03) for the REDS-III cohort, and 1.00 (95% CI, 1.00-1.01) for the SCANDAT cohort. For units from sex-discordant transfusions, hazard ratios were 1.02 (95% CI, 0.99-1.05) for the KPNC cohort, 0.99 (95% CI, 0.98-1.00) for the REDS-III cohort, and 1.00 (95% CI, 0.99-1.00) for the SCANDAT cohort.Conclusions and Relevance: Among red blood cell transfusion recipients, transfusions from female, previously pregnant, or sex-discordant donors were not significantly associated with increased mortality. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 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.Study Design and Methods: 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.Results: 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%).Conclusion: 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. [ABSTRACT FROM AUTHOR]

Blood group A was found to be associated with gastric cancer in the 1950s. Strikingly, for peptic ulcers an increased risk has been shown for blood group O. However, previous investigations have generally been poorly conducted and have failed to take a unifying approach to these observations. Using the Scandinavian Donations and Transfusions (referred to as “SCANDAT”) database, the authors established a cohort of Swedish and Danish blood donors with known blood type and followed these for the occurrence of gastric cancer and peptic ulcers through December 31, 2002. Cases were ascertained by using nationwide cancer and hospital registers. Altogether, 1,089,022 donors were followed for up to 35 years, during which 688 gastric cancer cases and 5,667 peptic ulcer cases accrued. Poisson regression analyses confirmed an increased risk of gastric cancer among individuals with blood group A (incidence rate ratio = 1.20, 95% confidence interval: 1.02, 1.42) and conversely that peptic ulcer risk was instead highest among those with blood group O. In this large, population-based cohort study, the authors have confirmed the association between blood group A and gastric cancer. In addition, they give further support to the notion that individuals with blood group O have a higher risk of peptic ulcers than those with other blood groups. [ABSTRACT FROM PUBLISHER]

The article discusses the relation between transfusion of concentrate stored red blood cell (RBC) and the adverse outcomes and survival after the cardiac surgery. The study used the data from patients who undergone heart valve surgery and coronary artery bypass graft surgery between 1997 and 2012 from SWEDEHEART register. Also mentioned the application of the multivariable Cox regression that estimate the risk of death in relative to the transfusion of RBCs storage.

Aim The aim of this study is to firmly delineate temporal and age trends regarding sex discrepancies in cancer risk and survival as well as quantifying the potential gain achieved by eliminating this inequality. Methods We performed a population-based cohort study using data on all adult incident cancer cases (n = 872,397) recorded in the Swedish Cancer Register in 1970–2014. To assess the associations between sex and cancer risk and sex and survival, male-to-female incidence rate ratios (IRRs) and excess mortality ratios (EMRs) adjusted for age and year of diagnosis were estimated using Poisson regression. Results Men were at increased risk for 34 of 39 and had poorer prognosis for 27 of 39 cancers. Women were at increased risk for 5 of 39 and had significantly poorer survival for 2 of 39 cancers. IRRs among male predominant sites ranged from 1.05; 95% confidence interval (CI), 1.03–-1.1 (lung adenocarcinoma) to 8.0; 95% CI, 7.5–8.5 (larynx). EMRs among sites with male survival disadvantage ranged from 1.1; 95% CI, 1.03–1.1 (colon) to 2.1; 95% CI, 1.5–-2.8 (well-differentiated thyroid). Conclusion Male sex is associated with increased risk and poorer survival for most cancer sites. Identifying and eliminating factors driving the observed sex differences may reduce the global cancer burden. [ABSTRACT FROM AUTHOR]

Introduction: The associations between ABO blood group and cancer risk have been studied repeatedly, but results have been variable. Consistent associations have only been reported for pancreatic and gastric cancers.Materials and Methods: We estimated associations between different ABO blood groups and site-specific cancer risk in a large cohort of healthy blood donors from Sweden and Denmark.Results: A total of 1.6 million donors were followed over 27 million person-years (20 million in Sweden and 7 million in Denmark). We observed 119,584 cancer cases. Blood groups A, AB and B were associated either with increased or decreased risk of cancer at 13 anatomical sites (p≤0.05), compared to blood group O. Consistent with assessment using a false discovery rate approach, significant associations with ABO blood group were observed for cancer of the pancreas, breast, and upper gastrointestinal tract (mouth, salivary glands, pharynx, esophageal adenocarcinoma and stomach).Discussion: Our study reconfirms the association between ABO blood group and cancer risk and exact underlying mechanisms involved needs further research. [ABSTRACT FROM AUTHOR]

Background: ABO blood groups have been shown to be associated with increased risks of venous thromboembolic and arterial disease. However, the reported magnitude of this association is inconsistent and is based on evidence from small-scale studies.Methods and Results: We used the SCANDAT2 (Scandinavian Donations and Transfusions) database of blood donors linked with other nationwide health data registers to investigate the association between ABO blood groups and the incidence of first and recurrent venous thromboembolic and arterial events. Blood donors in Denmark and Sweden between 1987 and 2012 were followed up for diagnosis of thromboembolism and arterial events. Poisson regression models were used to estimate incidence rate ratios as measures of relative risk. A total of 9170 venous and 24 653 arterial events occurred in 1 112 072 individuals during 13.6 million person-years of follow-up. Compared with blood group O, non-O blood groups were associated with higher incidence of both venous and arterial thromboembolic events. The highest rate ratios were observed for pregnancy-related venous thromboembolism (incidence rate ratio, 2.22; 95% confidence interval, 1.77-2.79), deep vein thrombosis (incidence rate ratio, 1.92; 95% confidence interval, 1.80-2.05), and pulmonary embolism (incidence rate ratio, 1.80; 95% confidence interval, 1.71-1.88).Conclusions: In this healthy population of blood donors, non-O blood groups explain >30% of venous thromboembolic events. Although ABO blood groups may potentially be used with available prediction systems for identifying at-risk individuals, its clinical utility requires further comparison with other risk markers. [ABSTRACT FROM AUTHOR]

Objective: There is an increasing focus on massive transfusion, but there is a paucity of comprehensive descriptions of the massively transfused patients and their outcomes. The objective of this study is to describe the incidence rate of massive transfusion, patient characteristics, and the mortality of massively transfused patients.Design: Descriptive cohort study.Setting: Nationwide study with data from Sweden and Denmark.Patients: The study was based on the Scandinavian Donations and Transfusions database, including all patients receiving 10 or more red cell concentrate transfusions in Sweden from 1987 and in Denmark from 1996. A total of 92,057 patients were included. Patients were followed until the end of 2012.Measurements and Main Results: Descriptive statistics were used to characterize the patients and indications. Post transfusion mortality was expressed as crude 30-day mortality and as long-term mortality using the Kaplan-Meier method and using standardized mortality ratios. The incidence of massive transfusion was higher in Denmark (4.5 per 10,000) than in Sweden (2.5 per 10,000). The most common indication for massive transfusion was major surgery (61.2%) followed by trauma (15.4%). Massive transfusion due to obstetrical bleeding constituted only 1.8%. The overall 5-year mortality was very high (54.6%), however with large differences between indication groups, ranging from 91.1% among those transfused for a malignant disease without surgery to 1.7% among patients transfused for obstetrical bleeding. The early standardized mortality ratios were high and decreased thereafter, but remained elevated throughout the time period.Conclusions: This large-scale study based on nationwide data from Sweden and Denmark describes the complete range of massive transfusion. We report a nonnegligible incidence and both a high absolute mortality and high standardized mortality ratio. The general pattern was similar for Sweden and Denmark, and we believe that similar patterns may be found in other high-resource countries. The study provides a relevant background for clinicians and researchers for designing future studies in this field. [ABSTRACT FROM AUTHOR]