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.
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).
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.
Data are presented on the retrospective epidemiological serological investigation of episodes of hepatitis-like diseases among plasma donors in Krasnoyarsk. A mixed structure of the focus was established with prevalence of B- and non-A-, non-B hepatitides. Markers of recent infection with HB virus were recorded in 43.6% of sick donors, at the same time no donors had IgM antibodies to hepatitis A evidencing the acute stage or early convalescence. The use of the insufficiently sensitive passive hemagglutination test for HBsAg identification has resulted in incomplete detection of donors-carriers of HB virus.
Following animal model data indicating the possible rejuvenating effects of blood from young donors, there have been at least 2 observational studies conducted with humans that have investigated whether donor age affects patient outcomes. Results, however, have been conflicting.
To study the association of donor age and sex with survival of patients receiving transfusions.
A retrospective cohort study based on the Scandinavian Donations and Transfusions database, with nationwide data, was conducted for all patients from Sweden and Denmark who received at least 1 red blood cell transfusion of autologous blood or blood from unknown donors between January 1, 2003, and December 31, 2012. Patients were followed up from the first transfusion until death, emigration, or end of follow-up. Data analysis was performed from September 15 to November 15, 2016.
The number of transfusions from blood donors of different age and sex. Exposure was treated time dependently throughout follow-up.
Hazard ratios (HRs) for death and adjusted cumulative mortality differences, both estimated using Cox proportional hazards regression.
Results of a crude analysis including 968?264 transfusion recipients (550?257 women and 418?007 men; median age at first transfusion, 73.0 years [interquartile range, 59.8-82.4 years]) showed a U-shaped association between age of the blood donor and recipient mortality, with a nadir in recipients for the most common donor age group (40-49 years) and significant and increasing HRs among recipients of blood from donors of successively more extreme age groups (
Notes
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The ABO records of 392 blood donors in the Isle of Bute, Scotland, showed a significant excess of group A and decrease of group O compared with data from the adjacent mainland. A survey by questionnaire to explain these observations assessed the representative nature of the donor panel as a sample of the Bute population, with respect to sex, age, occupation and origin by birthplace and parental birthplace. The reported motivations first prompting the Bute panel to donate blood were analysed, especially those liable to introduce bias into the results. It was concluded that: the informative 318 donors were not an atypical sample; inclusion of Younger Kindred enhanced the group A frequency; inclusion of donors with knowledge of their blood groups before enrolment as donors introduced a counter-bias in favour of group O; the raised group A frequency of the Incomers to the island was probably attributable to admixture of an English population with a non-Bute Scottish population; the Brandanes could represent a small indigenous island population in which the incidence of group A has become high, but, as numbers were small, a chance observation could not be excluded.
Regional Blood Transfusion Centre and Department of Clinical Immunology, Aarhus University Hospital (Skejby), Aarhus, Denmark. betinasamuelsen@yahoo.dk
Population-based data on the rate and outcome of complications related to blood donation are sparse.
Data from a survey conducted in 2003 in Aarhus County, Denmark, were used to assess the overall rate of donor complications. Additional nationwide data on moderate and severe donor complications were obtained from the Danish Register of Complications Related to Blood Donation, with records of all moderate and severe donor complications in Denmark occurring during the period 1997-2003.
In the regional survey, we identified 340 complications of any type among 41 274 donations, corresponding to a rate of 824/100,000 donations [95% confidence interval (CI): 741-916]. All complications were either needle injuries or vasovagal reactions. In the nationwide register, a total of 752 moderate and severe complications were recorded among 2,575,264 donations, corresponding to a rate of 29/100,000 donations (95% CI: 27-31). The rates of complications leading to long-term morbidity or disablement (> 5% loss of working capacity) were 5/100,000 donations (95% CI: 4.2-5.9) and 2.3/100,000 donations (95% CI: 1.8-2.9), respectively.
The risk of complications related to blood donation is low. However, attention towards donor complications is warranted, given the non-negligible rate of complications resulting in long-term morbidity and disablement.
Estimates of the viral residual risk should be updated to reflect current incidence of infection in blood donors. Incidence rates were estimated for allogeneic whole-blood donations made to Canadian Blood Services from 2006 to 2009 based on transmissible disease conversions of repeat donations within a 3-year period. Residual risk was estimated as the incidence multiplied by the window period. The residual risk of HIV was 1 per 8 million donations, HCV 1 per 6·7 million donations and HBV 1 per 1·7 million donations. The residual risk remains low and has decreased for HCV since our previous estimates due to reduced incidence.
Hepatitis C virus (HCV) rates have decreased steadily in first-time donors in Canada since testing was implemented but reasons are unclear. A description of factors that may have played a role in this decline is reported.
Descriptive analysis of first-time blood donors by HCV positivity status and year (1993--2006), sex, and age was carried out. HCV-positive first-time donors and matched controls participated in a confidential scripted telephone interview about risk factors in 1993 through 1994 and in 2005 through 2006, and risk factors independently predicting HCV positivity were determined with multiple logistic regression.
HCV-positive donations occurred most frequently in donors born between 1945 and 1964 and decreased in this birth cohort over time (p
To determine the diphtheria and tetanus antitoxin levels among blood donors in Toronto.
Cross-sectional seroprevalence study.
Two fixed-site blood-donation clinics in Toronto from September to November 1994.
Blood donors 20 years of age or older were eligible to participate; of the 781 eligible donors, 710 (90.9%) participated in the study.
Diphtheria and tetanus antitoxin levels and factors associated with disease susceptibility, such as vaccination history, country of birth, age and sex. A diphtheria antitoxin level lower than 0.01 lU/mL and a tetanus antitoxin level lower than 0.15 lU/mL were considered nonprotective.
Among the participants, 147 (20.7%) had a diphtheria antitoxin level in the nonprotective range, and 124 (17.5%) had a tetanus antitoxin level that was nonprotective. Increasing age and lack of written vaccination records were associated with susceptibility to the 2 diseases. Birth outside Canada was significantly related to tetanus susceptibility.
Adults over 50 years of age who did not know their vaccination history were the least likely to be protected against diphtheria and tetanus. The greatest benefit of any immunization strategy would be gained by targeting this group.
In many jurisdictions, blood donors who have an atypical pulse rate are temporarily deferred. This practice is not supported by evidence. We evaluated whether accepting donors with an atypical pulse rate increases their risk of cardiac ischaemic events.
We measured the cumulative incidence of hospitalizations and deaths for coronary heart disease within 1 year of follow-up among donors who, between 2002 and 2006, were temporarily deferred because of an atypical pulse (100 beats/min, or irregular). We compared this incidence to that observed among donors who also had an atypical pulse but who were allowed to donate, following a change in our deferral policy in 2007. The occurrence of cardiac events was determined through hospital discharge and death registries.
Among 6076 donors who were temporarily deferred for an atypical pulse, the 1-year rate of hospitalization or death for cardiac ischaemic events was 3.5/1000, compared to 2.4 in donors who had an atypical pulse but who were allowed to donate (n =10,671), for an adjusted odds ratio of 1.7 (95% CI, 0.9-3.0, P=0.08).
Regardless of the clinical significance of an atypical pulse rate, our data show that accepting donors with this condition does not increase the occurrence of serious cardiac ischaemic events. We conclude that pulse rate measurement in prospective donors is not warranted.
BACKGROUND: Long-term deleterious effects of repeated blood donations may be masked by the donors' healthy lifestyle. To investigate possible effects of blood donation and iron loss through blood donation on cancer incidence while minimizing "healthy donor effects," we made dose-response comparisons within a cohort of Swedish and Danish blood donors. METHODS: We used a nested case-control study design, in which case patients were defined as all donors who were diagnosed with a malignancy between their first recorded blood donation and study termination (n = 10866). Control subjects (n = 107140) were individually matched on sex, age, and county of residence. Using conditional logistic regression, we estimated relative risks of cancer according to number of blood donations made or estimated iron loss 3-12 years before a case patient was diagnosed with cancer. All statistical tests were two-sided. RESULTS: No clear association was observed between number of donations and risk of cancer overall. However, between the lowest ( 90th percentile, > 2.7 g) categories of estimated iron loss, there was a trend (P(trend) 25 vs 0 donations, OR = 2.14, 95% CI = 1.22 to 3.74). CONCLUSIONS: Repeated blood donation was not associated with increased or decreased risk of cancer overall. The lack of consistency across latency periods casts doubt on an apparent association between reduced cancer risk and iron loss in men. The positive association between frequent plasma donation and risk of non-Hodgkin lymphoma deserves further exploration.
