Socio-demographic characteristics of Danish blood donors

Blood donation projections using hierarchical time series forecasting: the case of Zimbabwe's national blood bank

BACKGROUND

The discrepancy between blood supply and demand requires accurate forecasts of the blood supply at any blood bank. Accurate blood donation forecasting gives blood managers empirical evidence in blood inventory management. The study aims to model and predict blood donations in Zimbabwe using hierarchical time series. The modelling technique allows one to identify, say, a declining donor category, and in that way, the method offers feasible and targeted solutions for blood managers to work on.

METHODS

The monthly blood donation data covering the period 2007 to 2018, collected from the National Blood Service Zimbabwe (NBSZ) was used. The data was disaggregated by gender and blood groups types within each gender category. The model validation involved utilising actual blood donation data from 2019 and 2020. The model's performance was evaluated through the Mean Absolute Percentage Error (MAPE), uncovering expected and notable discrepancies during the Covid-19 pandemic period only.

RESULTS

Blood group O had the highest monthly yield mean of 1507.85 and 1230.03 blood units for male and female donors, respectively. The top-down forecasting proportions (TDFP) under ARIMA, with a MAPE value of 11.30, was selected as the best approach and the model was then used to forecast future blood donations. The blood donation predictions for 2019 had a MAPE value of 14.80, suggesting alignment with previous years' donations. However, starting in April 2020, the Covid-19 pandemic disrupted blood collection, leading to a significant decrease in blood donation and hence a decrease in model accuracy.

CONCLUSIONS

The gradual decrease in future blood donations exhibited by the predictions calls for blood authorities in Zimbabwe to develop interventions that encourage blood donor retention and regular donations. The impact of the Covid-19 pandemic distorted the blood donation patterns such that the developed model did not capture the significant drop in blood donations during the pandemic period. Other shocks such as, a surge in global pandemics and other disasters, will inevitably affect the blood donation system. Thus, forecasting future blood collections with a high degree of accuracy requires robust mathematical models which factor in, the impact of various shocks to the system, on short notice.

Lifestyle and demographic associations with 47 inflammatory and vascular stress biomarkers in 9876 blood donors

BACKGROUND

The emerging use of biomarkers in research and tailored care introduces a need for information about the association between biomarkers and basic demographics and lifestyle factors revealing expectable concentrations in healthy individuals while considering general demographic differences.

METHODS

A selection of 47 biomarkers, including markers of inflammation and vascular stress, were measured in plasma samples from 9876 Danish Blood Donor Study participants. Using regression models, we examined the association between biomarkers and sex, age, Body Mass Index (BMI), and smoking.

RESULTS

Here we show that concentrations of inflammation and vascular stress biomarkers generally increase with higher age, BMI, and smoking. Sex-specific effects are observed for multiple biomarkers.

CONCLUSION

This study provides comprehensive information on concentrations of 47 plasma biomarkers in healthy individuals. The study emphasizes that knowledge about biomarker concentrations in healthy individuals is critical for improved understanding of disease pathology and for tailored care and decision support tools.

Establishing reference intervals for soluble urokinase plasminogen activator receptor in Northern European adults

Objectives

Soluble urokinase plasminogen activator receptor (suPAR) may have untapped potential in clinical diagnostics. Previous studies determined reference intervals using an enzyme-linked immunoassay, but there is a need for reference intervals using a faster assay if the analysis is to be used in emergency medicine. The current study aims to determine reference intervals for suPAR using a fully automated particle-enhanced turbidimetric immunoassay (PETIA) according to the Clinical and Laboratory Standards Institute guideline A28-A3c.

Design and methods

Blood samples were prospectively collected from Danish blood donors. Plasma suPAR was analyzed on the cobas 8000 module c502 in an open channel using a PETIA. Sex-partitioned reference intervals were determined using a parametric quantile approach.

Results

The study included 241 participants-123 females and 118 males. The common reference interval for suPAR was 1.56-4.11 ng/mL (95% confidence intervals (CI) for the lower and upper limits were 1.56-1.63 and 3.81-4.47, respectively). The reference interval for females was 1.59-4.65 ng/mL (95% CIs 1.48-1.70 and 4.09-5.48, respectively) and for males, 1.56-3.59 ng/mL (95% CIs 1.47-1.65 and 3.31-3.93, respectively).

Conclusions

Our results support using sex-partitioned reference intervals for suPAR and provide a basis for future studies using the PETIA method.

Medium term moderate to low-level air pollution exposure is associated with higher C-reactive protein among healthy Danish blood donors

Air pollution is a significant contributor to the global burden of disease with a plethora of associated health effects such as pulmonary and systemic inflammation. C-reactive protein (CRP) is associated with a wide range of diseases and is associated with several exposures. Studies on the effect of air pollution exposure on CRP levels in low to moderate pollution settings have shown inconsistent results. In this cross-sectional study high sensitivity CRP measurements on 18,463 Danish blood donors were linked to modelled air pollution data for NOx, NO2, O3, CO, SO2, NH3, mineral dust, black carbon, organic carbon, sea salt, secondary inorganic aerosols and its components, primary PM2.5, secondary organic aerosols, total PM2.5, and total PM10 at their residential address over the previous month. Associations were analysed using ordered logistic regression with CRP quartile as individuals outcome and air pollution exposure as scaled deciles. Analyses were adjusted for health related and socioeconomic covariates using health questionnaires and Danish register data. Exposure to different air pollution components was generally associated with higher CRP (odds ratio estimates ranging from 1.11 to 1.67), while exposure to a few air pollution components was associated with lower CRP. For example, exposure to NO2 increased the odds of high CRP 1.32-fold (95%CI 1.16-1.49), while exposure to NH3 decreased the odds of high CRP 0.81-fold (95%CI 0.73-0.89). This large study among healthy individuals found air pollution exposure to be associated with increased levels of CRP even in a setting with low to moderate air pollution levels.

Establishing Sex-Dependent Reference Intervals for KL-6 in Danish Adults

Krebs von den Lungen-6 (KL-6) is a promising biomarker for the diagnosis and prognosis of interstitial lung disease. However, reference intervals in Northern Europeans remain to be established using a latex-particle-enhanced turbidimetric immunoassay. The participants were Danish blood donors subjected to strict health requirements. Analyses were performed using the Nanopia KL-6 reagent on the cobas 8000 module c502. Sex-partitioned reference intervals were determined using a parametric quantile approach according to the Clinical and Laboratory Standards Institute guideline EP28-A3c. The study included 240 participants-121 females and 119 males. The common reference interval was 59.4-398.5 U/mL (95% confidence intervals (CI) for the lower and upper limits were 47.3-71.9 and 369.5-430.1, respectively). For females, the reference interval was 56.8-324.0 U/mL (95% CIs for the lower and upper limits were 36.1-77.6 and 303.3-344.7, respectively). For males, the reference interval was 51.5-448.7 U/mL (95% CIs for the lower and upper limits were 32.8-71.2 and 397.3-508.1, respectively). These results emphasize the importance of sex partitioning when evaluating KL-6 reference intervals. The reference intervals increase the clinical applicability of the KL-6 biomarker and provide a basis for future scientific studies of its utility in patient management.

Developmental language disorder - a comprehensive study of more than 46,000 individuals

Developmental language disorder (DLD) is characterized by enduring low language abilities with a significant functional impact, in the absence of biomedical conditions in which language impairment is part of a complex of impairments. There is a lack of awareness of DLD even among healthcare professionals. Here we estimated the prevalence of DLD and its links to reading and learning difficulties and physical and mental health in the Danish Blood Donor Study (N = 46,547), where DLD-related information is based on questionnaires (self-report). We compared the questionnaire-derived DLD status with the relevant language-related diagnoses from hospital registers. We also investigated the genetic architecture of DLD in a subset of the cohort (N = 18,380). DLD was significantly associated with reading and learning difficulties and poorer mental and physical health. DLD prevalence was 3.36%-3.70% based on questionnaires, compared with 0.04% in hospital registers. Our genetic analyses identified one genome-wide significant locus, but not a significant heritability estimate. Our study shows that DLD has health-related implications that may last into adulthood, and that DLD may be undiagnosed in general healthcare. Furthermore, DLD is likely more genetically heterogeneous than narrower developmental language phenotypes. Our results emphasize the need to raise awareness of DLD and consider criteria for molecular studies of DLD to reduce case heterogeneity.

A Review of Major Danish Biobanks: Advantages and Possibilities of Health Research in Denmark

Biobank research may lead to an improved understanding of disease etiology and advance personalized medicine. Denmark (population ~5.9 million) provides a unique setting for population-based health research. The country is a rich source of biobanks and the universal, tax-funded healthcare system delivers routinely collected data to numerous registries and databases. By virtue of the civil registration number (assigned uniquely to all Danish citizens), biological specimens stored in biobanks can be combined with clinical and demographic data from these population-based health registries and databases. In this review, we aim to provide an understanding of advantages and possibilities of biobank research in Denmark. As knowledge about the Danish setting is needed to grasp the full potential, we first introduce the Danish healthcare system, the Civil Registration System, the population-based registries, and the interface with biobanks. We then describe the biobank infrastructures, comprising the Danish National Biobank Initiative, the Bio- and Genome Bank Denmark, and the Danish National Genome Center. Further, we briefly provide an overview of fourteen selected biobanks, including: The Danish Newborn Screening Biobank; The Danish National Birth Cohort; The Danish Twin Registry Biobank; Diet, Cancer and Health; Diet, Cancer and Health - Next generations; Danish Centre for Strategic Research in Type 2 Diabetes; Vejle Diabetes Biobank; The Copenhagen Hospital Biobank; The Copenhagen City Heart Study; The Copenhagen General Population Study; The Danish Cancer Biobank; The Danish Rheumatological Biobank; The Danish Blood Donor Study; and The Danish Pathology Databank. Last, we inform on practical aspects, such as data access, and discuss future implications.

The healthy donor effect and survey participation, becoming a donor and donor career

BACKGROUND

The healthy donor effect (HDE) is a selection bias caused by the health criteria blood donors must meet. It obscures investigations of beneficial/adverse health effects of blood donation and complicates the generalizability of findings from blood donor cohorts. To further characterize the HDE we investigated how self-reported health and lifestyle are associated with becoming a blood donor, lapsing, and donation intensity. Furthermore, we examined differences in mortality based on donor status.

STUDY DESIGN AND METHODS

The Danish National Health Survey was linked to the Scandinavian Donations and Transfusions (SCANDAT) database and Danish register data. Logistic- and normal regression was used to compare baseline characteristics and participation. Poisson regression was used to investigate future donation choices. Donation intensity was explored by the Anderson-Gill model and Poisson regression. Mortality was investigated using Poisson regression.

RESULTS

Blood donors were more likely to participate in the surveys, OR = 2.45 95% confidence interval (2.40-2.49) than non-donors. Among survey participants, better self-reported health and healthier lifestyle were associated with being or becoming a blood donor, donor retention, and to some extent donation intensity, for example, current smoking conveyed lower likelihood of becoming a donor, OR = 0.70 (0.66-0.75). We observed lower mortality for donors and survey participants, respectively, compared with non-participating non-donors.

CONCLUSION

We provide evidence that blood donation is associated with increased likelihood to participate in health surveys, possibly a manifestation of the HDE. Furthermore, becoming a blood donor, donor retention, and donation intensity was associated with better self-reported health and healthier lifestyles.

Prevalence of major depressive disorder in 51,658 otherwise healthy adult Danes: Sex differences in symptomatology and prediction of future anti-depressive medication

Major Depressive Disorder (MDD) is a heterogeneous disease, which displays sex differences in symptomatology. This study aimed to assess point prevalence of MDD in undiagnosed, healthy adults as well as sex differences in symptomatology and clarify if specific symptoms increased the later need for anti-depressive medication. The study included 51,658 blood donors. Depressive symptoms were assessed according to ICD-10 using the Major Depression Inventory. Demographics, previous MDD, anti-depressive medication were collected from questionnaires and population registers. Descriptive, Logistic and Cox regression analyses were conducted. In total, 1.15% participants met the criteria for MDD. Women were significantly more likely to experience "increased appetite" and less likely to experience "a feeling of life not worth living", compared to men. MDD significantly associated with an increased hazard of later receiving a prescription for anti-depressive medication. The risk increased proportionally with increasing MDD severity. The two symptoms, "feeling that life is not worth living" and "trouble sleeping" were the strongest individual predictive symptoms of future anti-depressive medication in women and men, respectively. The results confirm findings in MDD patient groups. The diagnostic and prognostic value should be investigated further to address their potential as part of the clinical assessment.

A Markov jump process approach to modeling blood donor status: Donor retention and attrition rates at a blood service center in Zimbabwe

Background

Blood service agencies depend upon the availability of regular blood donors for sustainability. The knowledge and understanding of the stochastic behavior of donors is the first step toward sustaining the blood supply. Analyzing the changes in the donor status within the donor pool will help the blood service authorities to manage the blood donation process.

Objectives

The study presents a multistate Markov jump model in analyzing the changes in blood donor status during their blood donation career. Relevant covariates are used to aid in explaining the transitions.

Materials and Methods

The status of a blood donor i that can be in one of four states S = {1; 2; 3; 4}. A new donor (s = 1), repeat/regular donor (s = 2), occasional donor (s = 3), and lapsed donor (s = 4). A Continuous‐time Markov model was used to estimate blood donor progression during their blood donation career. Frequencies of blood donations made in a given time interval determines the state occupied.

Results

In the early years of blood donation career, first‐time donors have a higher likelihood of becoming regular donors. Donor attrition increases with time whilst donor retention decreases with time. The results show that when the jump process is currently in an occasional state, the probability that it moves into lapsed state when it leaves the occasional state is given as 69.06%. Similarly, donors are forecasted to spend 21.193 months (1.8 years) in the occasional state before lapsing. Repeat donors can spend 39.342 months (3.3 years) in the regular state before the transition to other states. The study established that donor‐specific demographic factors such as age and gender are critical in donor status transitions.

Conclusions

With the passage of time, donor status evolves, with trend inclined towards reduction in the frequency of blood donations as more donors become inactive or lapsed. The transition of donors in various states can be described by a time homogeneous Markov model.

Serological testing of blood donors to characterise the impact of COVID-19 in Melbourne, Australia, 2020

Rapidly identifying and isolating people with acute SARS-CoV-2 infection has been a core strategy to contain COVID-19 in Australia, but a proportion of infections go undetected. We estimated SARS-CoV-2 specific antibody prevalence (seroprevalence) among blood donors in metropolitan Melbourne following a COVID-19 outbreak in the city between June and September 2020. The aim was to determine the extent of infection spread and whether seroprevalence varied demographically in proportion to reported cases of infection. The design involved stratified sampling of residual specimens from blood donors (aged 20–69 years) in three postcode groups defined by low (<3 cases/1,000 population), medium (3–7 cases/1,000 population) and high (>7 cases/1,000 population) COVID-19 incidence based on case notification data. All specimens were tested using the Wantai SARS-CoV-2 total antibody assay. Seroprevalence was estimated with adjustment for test sensitivity and specificity for the Melbourne metropolitan blood donor and residential populations, using multilevel regression and poststratification. Overall, 4,799 specimens were collected between 23 November and 17 December 2020. Seroprevalence for blood donors was 0.87% (90% credible interval: 0.25–1.49%). The highest estimates, of 1.13% (0.25–2.15%) and 1.11% (0.28–1.95%), respectively, were observed among donors living in the lowest socioeconomic areas (Quintiles 1 and 2) and lowest at 0.69% (0.14–1.39%) among donors living in the highest socioeconomic areas (Quintile 5). When extrapolated to the Melbourne residential population, overall seroprevalence was 0.90% (0.26–1.51%), with estimates by demography groups similar to those for the blood donors. The results suggest a lack of extensive community transmission and good COVID-19 case ascertainment based on routine testing during Victoria’s second epidemic wave. Residual blood donor samples provide a practical epidemiological tool for estimating seroprevalence and information on population patterns of infection, against which the effectiveness of ongoing responses to the pandemic can be assessed.

Ramadan favors first blood donation, but not frequent donation: Results of 10,145 blood donors from Algeria

CONTEXT

Frequent blood donors contribute to an important share of blood donations in many countries. In Algeria, frequent donation and its determinants, notably the place of the month of Ramadan, which plays an important role in blood donation in Muslim countries, have not been studied.

METHODS

This was a retrospective cohort study of n = 10145 Algerians who donated blood to the blood transfusion post (BTP) of Boufarik between January 2, 2008, and December 31, 2019. Donors were assessed at each donation for general clinical information, demographic information, and dates and times of donation. Donor return, defined as two or more donations to Boufarik BTP, and frequent donation, defined as three or more blood donations to Boufarik BTP, were the outcomes of interest and were analyzed using groups comparison and logistic and Cox regression analyses.

RESULTS

2.2% of donors were frequent donors and donated 9.6% of all donated blood. The volume of donated blood during Ramadan was twice the monthly volume during the rest of the year, but donation in Ramadan was associated with lower odds of return (odds ratio [OR]: 0.54, 95% confidence interval [CI]: 0.40-0.71) and frequent donation (OR: 0.41, 95% CI: 0.24-0.73). Women were underrepresented (10.9%), but they were more likely to be frequent donors (male vs. female OR: 0.55, 95% CI: 0.31-0.96; hazard ratio: 0.64, 95% CI: 0.41-0.98).

CONCLUSIONS

Reducing the gender gap and promoting return could significantly improve the volume of blood donations in Algeria.

Cohort profile: Copenhagen Hospital Biobank - Cardiovascular Disease Cohort (CHB-CVDC): Construction of a large-scale genetic cohort to facilitate a better understanding of heart diseases

PURPOSE

The aim of Copenhagen Hospital Biobank-Cardiovascular Disease Cohort (CHB-CVDC) is to establish a cohort that can accelerate our understanding of CVD initiation and progression by jointly studying genetics, diagnoses, treatments and risk factors.

PARTICIPANTS

The CHB-CVDC is a large genomic cohort of patients with CVD. CHB-CVDC currently includes 96 308 patients. The cohort is part of CHB initiated in 2009 in the Capital Region of Denmark. CHB is continuously growing with ~40 000 samples/year. Patients in CHB were included in CHB-CVDC if they were above 18 years of age and assigned at least one cardiovascular diagnosis. Additionally, up-to 110 000 blood donors can be analysed jointly with CHB-CVDC. Linkage with the Danish National Health Registries, Electronic Patient Records, and Clinical Quality Databases allow up-to 41 years of medical history. All individuals are genotyped using the Infinium Global Screening Array from Illumina and imputed using a reference panel consisting of whole-genome sequence data from 8429 Danes along with 7146 samples from North-Western Europe. Currently, 39 539 of the patients are deceased.

FINDINGS TO DATE

Here, we demonstrate the utility of the cohort by showing concordant effects between known variants and selected CVDs, that is, >93% concordance for coronary artery disease, atrial fibrillation, heart failure and cholesterol measurements and 85% concordance for hypertension. Furthermore, we evaluated multiple study designs and the validity of using Danish blood donors as part of CHB-CVDC. Lastly, CHB-CVDC has already made major contributions to studies of sick sinus syndrome and the role of phytosterols in development of atherosclerosis.

FUTURE PLANS

In addition to genetics, electronic patient records, national socioeconomic and health registries extensively characterise each patient in CHB-CVDC and provides a promising framework for improved understanding of risk and protective variants. We aim to include other measurable biomarkers for example, proteins in CHB-CVDC making it a platform for multiomics cardiovascular studies.

Pain sensitivity in men who have never experienced a headache: an observer blinded case control study

Background

Headache affects 90–99% of the population. Based on the question “Do you think that you never ever in your whole life have had a headache?” 4% of the population say that they have never experienced a headache. The rarity of never having had a headache suggests that distinct biological and environmental factors may be at play. We hypothesized that people who have never experienced a headache had a lower general pain sensitivity than controls.

Methods

We included 99 male participants, 47 headache free participants and 52 controls, in an observer blinded nested case-control study. We investigated cold pain threshold and heat pain threshold using a standardized quantitative sensory testing protocol, pericranial tenderness with total tenderness score and pain tolerance with the cold pressor test. Differences between the two groups were assessed with the unpaired Student’s t-test or Mann-Whitney U test as appropriate.

Results

There was no difference in age, weight or mean arterial pressure between headache free participants and controls. We found no difference in pain detection threshold, pericranial tenderness or pain tolerance between headache free participants and controls.

Conclusion

Our study clearly shows that freedom from headache is not caused by a lower general pain sensitivity. The results support the hypothesis that headache is caused by specific mechanisms, which are present in the primary headache disorders, rather than by a decreased general sensitivity to painful stimuli.

Trial registration

Registered at ClinicalTrials.gov (NCT04217616), 3rd January 2020, retrospectively registered.

Prevalences of comorbid anxiety disorder and daily smartphone-based self-reported anxiety in patients with newly diagnosed bipolar disorder

BACKGROUND

Around 40% of patients with bipolar disorder (BD) additionally have anxiety disorder. The prevalence of anxiety in patients with newly diagnosed BD and their first-degree relatives (UR) has not been investigated.ObjectiveTo investigate (1) the prevalence of a comorbid anxiety diagnosis in patients with newly diagnosed BD and their UR, (2) sociodemographic and clinical differences between patients with and without a comorbid anxiety diagnosis and (3) the association between smartphone-based patient-reported anxiety and observer-based ratings of anxiety and functioning, respectively.

METHODS

We recruited 372 patients with BD and 116 of their UR. Daily smartphone-based data were provided from 125 patients. SCAN was used to assess comorbid anxiety diagnoses.

FINDINGS

In patients with BD, the prevalence of a comorbid anxiety disorder was 11.3% (N=42) and 10.3% and 5.9% in partial and full remission, respectively. In UR, the prevalence was 6.9%. Patients with a comorbid anxiety disorder had longer illness duration (p=0.016) and higher number of affective episodes (p=0.011). Smartphone-based patient-reported anxiety symptoms were associated with ratings of anxiety and impaired functioning (p<0.001).

LIMITATIONS

The SCAN interviews to diagnose comorbid anxiety disorder were carried out regardless of the participants' mood state.Clinical implicationsThe lower prevalence of anxiety in newly diagnosed BD than in later stages of BD indicates that anxiety increases with progression of BD. Comorbid anxiety seems associated with poorer clinical outcomes and functioning and smartphones are clinically useful for monitoring anxiety symptoms.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT02888262).

Reconciling estimates of global spread and infection fatality rates of COVID-19: An overview of systematic evaluations

BACKGROUND

Estimates of community spread and infection fatality rate (IFR) of COVID-19 have varied across studies. Efforts to synthesize the evidence reach seemingly discrepant conclusions.

METHODS

Systematic evaluations of seroprevalence studies that had no restrictions based on country and which estimated either total number of people infected and/or aggregate IFRs were identified. Information was extracted and compared on eligibility criteria, searches, amount of evidence included, corrections/adjustments of seroprevalence and death counts, quantitative syntheses and handling of heterogeneity, main estimates and global representativeness.

RESULTS

Six systematic evaluations were eligible. Each combined data from 10 to 338 studies (9-50 countries), because of different eligibility criteria. Two evaluations had some overt flaws in data, violations of stated eligibility criteria and biased eligibility criteria (eg excluding studies with few deaths) that consistently inflated IFR estimates. Perusal of quantitative synthesis methods also exhibited several challenges and biases. Global representativeness was low with 78%-100% of the evidence coming from Europe or the Americas; the two most problematic evaluations considered only one study from other continents. Allowing for these caveats, four evaluations largely agreed in their main final estimates for global spread of the pandemic and the other two evaluations would also agree after correcting overt flaws and biases.

CONCLUSIONS

All systematic evaluations of seroprevalence data converge that SARS-CoV-2 infection is widely spread globally. Acknowledging residual uncertainties, the available evidence suggests average global IFR of ~0.15% and ~1.5-2.0 billion infections by February 2021 with substantial differences in IFR and in infection spread across continents, countries and locations.

Blood donation in times of crisis: Early insight into the impact of COVID-19 on blood donors and their motivation to donate across European countries

Background

In this survey, we aimed to provide early insight into the impact of COVID‐19 on blood donors and their motivation to donate during the crisis.

Study design and methods

We asked representative samples in 7 European countries (Denmark, France, Germany, Italy, Portugal, the Netherlands and the UK) about their blood donation activity and motivation to donate using an online survey. We analysed donor turnout during the COVID‐19 period descriptively and using logistic regression.

Results

Of the 7122 people that responded to the survey, 1205 (16·9%) blood donors were identified, with 33·8% donating during the first 4–5 months of the COVID‐19 period. We observed that around half of donors donated less than normal. The vast majority of donors that did donate made a special effort to do so in response to COVID‐19. The majority of donors were also not aware of their blood being tested for COVID‐19 antibodies. Although the perceived risk of infection among all respondents whilst donating blood was relatively low, those who anticipated a high risk of infection were much less likely to donate (OR = 0·540; P‐value = 0·006). Furthermore, those that were adherent to COVID guidelines were also less likely to donate (OR = 0·583; P‐value = 0·000).

Discussion

We suggest that blood collection services consider specialist campaigns that focus on the altruistic motivation of donors during the crisis and that they continue to communicate the additional safety measures in place with the aim of reducing the fear of infection whilst donating blood.

The impact of health-related quality of life and depressive symptoms on blood donor career-Results from the Danish blood donor study

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.

Estimation of SARS-CoV-2 Infection Fatality Rate by Real-time Antibody Screening of Blood Donors

Background

The pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has tremendous consequences for our societies. Knowledge of the seroprevalence of SARS-CoV-2 is needed to accurately monitor the spread of the epidemic and to calculate the infection fatality rate (IFR). These measures may help the authorities make informed decisions and adjust the current societal interventions. The objective was to perform nationwide real-time seroprevalence surveying among blood donors as a tool to estimate previous SARS-CoV-2 infections and the population-based IFR.

Methods

Danish blood donors aged 17–69 years giving blood 6 April to 3 May were tested for SARS-CoV-2 immunoglobulin M and G antibodies using a commercial lateral flow test. Antibody status was compared between geographical areas, and an estimate of the IFR was calculated. Seroprevalence was adjusted for assay sensitivity and specificity taking the uncertainties of the test validation into account when reporting the 95% confidence intervals (CIs).

Results

The first 20 640 blood donors were tested, and a combined adjusted seroprevalence of 1.9% (95% CI, .8–2.3) was calculated. The seroprevalence differed across areas. Using available data on fatalities and population numbers, a combined IFR in patients <70 years is estimated at 89 per 100 000 (95% CI, 72–211) infections.

Conclusions

The IFR was estimated to be slightly lower than previously reported from other countries not using seroprevalence data. The IFR is likely severalfold lower than the current estimate. We have initiated real-time nationwide anti–SARS-CoV-2 seroprevalence surveying of blood donations as a tool in monitoring the epidemic.

Estimation of SARS-CoV-2 Infection Fatality Rate by Real-time Antibody Screening of Blood Donors

BACKGROUND

The pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has tremendous consequences for our societies. Knowledge of the seroprevalence of SARS-CoV-2 is needed to accurately monitor the spread of the epidemic and to calculate the infection fatality rate (IFR). These measures may help the authorities make informed decisions and adjust the current societal interventions. The objective was to perform nationwide real-time seroprevalence surveying among blood donors as a tool to estimate previous SARS-CoV-2 infections and the population-based IFR.

METHODS

Danish blood donors aged 17-69 years giving blood 6 April to 3 May were tested for SARS-CoV-2 immunoglobulin M and G antibodies using a commercial lateral flow test. Antibody status was compared between geographical areas, and an estimate of the IFR was calculated. Seroprevalence was adjusted for assay sensitivity and specificity taking the uncertainties of the test validation into account when reporting the 95% confidence intervals (CIs).

RESULTS

The first 20 640 blood donors were tested, and a combined adjusted seroprevalence of 1.9% (95% CI, .8-2.3) was calculated. The seroprevalence differed across areas. Using available data on fatalities and population numbers, a combined IFR in patients <70 years is estimated at 89 per 100 000 (95% CI, 72-211) infections.

CONCLUSIONS

The IFR was estimated to be slightly lower than previously reported from other countries not using seroprevalence data. The IFR is likely severalfold lower than the current estimate. We have initiated real-time nationwide anti-SARS-CoV-2 seroprevalence surveying of blood donations as a tool in monitoring the epidemic.

Oxygen in Red Blood Cell Concentrates: Influence of Donors' Characteristics and Blood Processing

Objective: Unexpectedly wide distribution (<10 to >90%) of hemoglobin oxygen saturation (sO₂) within red cell concentrates (RCCs) has recently been observed. Causes of such variability are not yet completely explained whereas the roles of oxygen and oxidative lesions during the storage of RCCs are known. The objectives of the present study are to characterize sO₂ distribution in RCCs produced in a Swiss blood center and to investigate the influence of processing and donors’ characteristics.

Methods: The level of sO₂ was measured in 1701 leukocyte-depleted RCCs derived from whole blood donations in both top–bottom (TB; component filtered, SAGM) and top–top (TT; whole blood filtration, PAGGSM) RCCs. The sO₂ value was measured non-invasively through the PVC bag prior to storage by resonance Raman spectroscopy. Gender, age, blood type, hemoglobin level, and living altitude of donors, as well as process method and time-to-process were recorded.

Results: Overall, the sO₂ exhibited a wide non-Gaussian distribution with a mean of 51.2 ± 18.5%. Use of top-top kits resulted in a 16% higher sO₂ (P < 0.0001) than with top-bottom ones. Waiting time before processing only had a modest impact, but the blood processing itself reduced the sO₂ by almost 12% (P < 0.0001). sO₂ was also significantly affected by some donors’ characteristics. RCCs from men exhibited 25% higher sO₂ (P < 0.0001) than those donated by women. Multivariate analysis revealed that the apparent correlation observed with hemoglobin level and age was actually due to multicollinearity with the sex variable. Finally, we noticed no significant differences across blood type but found that altitude of residence was associated with the sO₂ (i.e., higher in higher living place).

Conclusion: These data confirm wide sO₂ distribution in RCCs reported recently. The sO₂ was impacted by the processing and also by donors’ characteristics such as the gender and the living altitude, but not by the hemoglobin level, blood group and donor age. This study provides new hints on the factors influencing red blood cells storage lesions, since they are known to be related to O₂ content within the bags, giving clues to better process and to better store RCCs and therefore potentially improve the efficacy of transfusion.

Automatically Generated Smartphone Data in Young Patients With Newly Diagnosed Bipolar Disorder and Healthy Controls

Background: Smartphones may facilitate continuous and fine-grained monitoring of behavioral activities via automatically generated data and could prove to be especially valuable in monitoring illness activity in young patients with bipolar disorder (BD), who often present with rapid changes in mood and related symptoms. The present pilot study in young patients with newly diagnosed BD and healthy controls (HC) aimed to (1) validate automatically generated smartphone data reflecting physical and social activity and phone usage against validated clinical rating scales and questionnaires; (2) investigate differences in automatically generated smartphone data between young patients with newly diagnosed BD and HC; and (3) investigate associations between automatically generated smartphone data and smartphone-based self-monitored mood and activity in young patients with newly diagnosed BD. Methods: A total of 40 young patients with newly diagnosed BD and 21 HC aged 15-25 years provided daily automatically generated smartphone data for 3-779 days [median (IQR) = 140 (11.5-268.5)], in addition to daily smartphone-based self-monitoring of activity and mood. All participants were assessed with clinical rating scales. Results: (1) The number of outgoing phone calls was positively associated with scores on the Young Mania Rating Scale and subitems concerning activity and speech. The number of missed calls (p = 0.015) and the number of outgoing text messages (p = 0.017) were positively associated with the level of psychomotor agitation according to the Hamilton Depression Rating scale subitem 9. (2) Young patients with newly diagnosed BD had a higher number of incoming calls compared with HC (BD: mean = 1.419, 95% CI: 1.162, 1.677; HC: mean = 0.972, 95% CI: 0.637, 1.308; p = 0.043) and lower self-monitored mood and activity (p's < 0.001). (3) Smartphone-based self-monitored mood and activity were positively associated with step counts and the number of outgoing calls, respectively (p's < 0.001). Conclusion: Automatically generated data on physical and social activity and phone usage seem to reflect symptoms. These data differ between young patients with newly diagnosed BD and HC and reflect changes in illness activity in young patients with BD. Automatically generated smartphone-based data could be a useful clinical tool in diagnosing and monitoring illness activity in young patients with BD.

Long-term return and donation pattern of those who begin donating at different ages: A retrospective cohort analysis of blood donors in Australia

BACKGROUND

This study compared the likelihood of return to donate and donation rate ratio by age of donors at their first donation when followed up to 12 years.

STUDY DESIGN AND METHODS

Donation history of two cohorts of first-time donors (those donating in 2007 and 2013) was extracted until March 2019 from Australian Red Cross Lifeblood's national database. Poisson regression analyses compared donor return and negative-binomial regression estimated the rate ratio of donations.

RESULTS

A total of 120 469 and 95 381 donors were included in the 2007 and 2013 cohorts, respectively. Compared to donors aged 20-24 years, the likelihood of return in both cohorts increased consistently as age at first donation increased from 30-years and above. Average number of whole-blood and plasmapheresis donations increased as the age at first donation increased from 30-years onward. The whole-blood donation rate was highest for donors ≥60 years, while plasmapheresis donation rate was highest for donors aged 50-59 years. These patterns were largely consistent when stratified by sex.

CONCLUSIONS

To continuously ensure the short- to mid-term sufficiency of blood supply in Australia, targeted recruitment of donors aged 30-years and above may be considered, however its feasibility and impact should be explored further given relatively smaller proportion of new donors are middle-aged and older under current policies. Future studies with a longer follow-up period are needed to examine whether the frequency of donation among those who start donating at a younger age increases later in their life when they are 30-years or over.

SARS-CoV-2 infection fatality rate among elderly retired Danish blood donors - A cross-sectional study

BACKGROUND

Despite the vast majority of individuals succumbing to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are elderly, infection fatality rate (IFR) estimates for the age group 70 years older are still scarce. To this end we assessed SARS-CoV-2 seroprevalence among retired blood donors and combined it with national COVID-19 survey data to provide reliable population-based IFR estimates for this age group.

METHODS

We identified 60,926 retired blood donors age 70 years or older in the rosters of three region-wide Danish blood banks and invited them to fill in a questionnaire on COVID-19 related symptoms and behaviours. Among 24,861 (40.8%) responders, we invited a random sample of 3,200 individuals for blood testing. Overall, 1,201 (37.5%) individuals were tested for SARS-CoV-2 antibodies (Wantai) and compared to 1,110 active blood donors age 17-69 years. Seroprevalence 95% confidence intervals (CI) were adjusted for assay sensitivity and specificity.

RESULTS

Among retired (age 70 years or older) and active (age 17-69 years) blood donors, adjusted seroprevalences were 1.4% (95% CI: 0.3%-2.5%) and 2.5% (95% CI: 1.3%-3.8%), respectively. Using available population data on COVID-19 related fatalities, IFRs for patients age 70 years or older and for 17-69 years were estimated at 5.4% (95% CI: 2.7%-6.4%) and 0.083% (95% CI: 0.054%-0.18%), respectively. Only 52.4% of SARS-CoV-2 seropositive retired blood donors reported having been sick since the start of the pandemic.

CONCLUSION

COVID-19 IFR in the age group above 69 years is estimated to be 65 times as high as the IFR for people age 18-69 years.

Are Croatian blood donors obese?

The rising prevalence of overweight and obesity is characterized as a pandemic of the modern era. The purpose of this study was to analyze the prevalence of overweight and obesity in healthy blood donors in Primorje-Gorski Kotar County, Croatia, and the relationship between socio-demographic factors, lifestyle and eating habits, and body mass index (BMI), including the association of these factors with overweight and obesity. This cross-sectional study included 1255 healthy individuals aged between 18 and 70 years who donated blood between January 2015 and October 2016 at the Clinical Institute of Transfusion Medicine. Each participant completed a questionnaire regarding weight, height, blood type, socio-demographic factors, health parameters, physical activity, alcohol consumption, and smoking habits. Overweight was defined as BMI of 25-29.9 kg/m², and obesity as BMI ≥30 kg/m². A logistic regression model was used on data assessment. BMI was normal in 33.6% of participants, whereas 44.1% were overweight and 21.8% were obese. Higher BMI was correlated with male sex (odds ratio [OR]=0.21), lower education level (OR=0.77) and unhealthy diet (OR=0.57), whereas lower BMI was correlated with lower age (OR=2.05) and unemployment (OR=1.85). To our knowledge, this is the first study to investigate the prevalence of BMI in a healthy Croatian population; our results confirmed the findings of studies conducted in other European countries. Our results highlighted the importance of improving education levels and raising awareness of healthy dietary habits in high-risk groups, i.e. men and older individuals with lower education levels.

Prevalence and socio-demographic characteristics of persons who have never had a headache among healthy voluntary blood donors - a population-based study

INTRODUCTION

Headache is an extremely prevalent disorder with a lifetime prevalence of 90-99%. However, a small fraction of people never experiences a headache. Research on people without headache could uncover protective factors in headache, but to our knowledge no study on headache-free individuals has been published. We aim to estimate the prevalence of headache-free individuals among Danish blood donors, and to describe the socio-demographics and health factors of headache-free participants.

MATERIALS AND METHODS

In all, 38,557 healthy volunteers were recruited as part of the Danish Blood Donor Study. Headache-free participants were identified based on the question "Have you ever experienced a headache of any kind?". Utilising the Danish registries and self-reported questionnaires, we analysed socio-demographic and lifestyle factors using logistic regression adjusted for age and sex.

RESULTS

The prevalence of headache-free individuals was 4.1% (n = 1362) with a female-male ratio of 1:2.2. To be headache free was significantly associated with an employment status as a student, a low level of income and a regular alcohol consumption.

DISCUSSION

The prevalence of headache-free individuals was comparable to population-wide studies of headache. To be headache free was not associated with a high socio-economic status. Further studies on people without headache will hopefully reveal protective factors in headache, and this novel approach might be useful in other very prevalent disorders.

Primary Epstein-Barr virus infection with and without infectious mononucleosis

Background

Infectious mononucleosis (IM) is a common adverse presentation of primary infection with Epstein-Barr virus (EBV) in adolescence and later, but is rarely recognized in early childhood where primary EBV infection commonly occurs. It is not known what triggers IM, and also not why IM risk upon primary EBV infection (IM attack rate) seemingly varies between children and adolescents. IM symptoms may be severe and persist for a long time. IM also markedly elevates the risk of Hodgkin lymphoma and multiple sclerosis for unknown reasons. The way IM occurrence depends on age and sex is incompletely described and hard to interpret etiologically, because it depends on three quantities that are not readily observable: the prevalence of EBV-naϊve persons, the hazard rate of seroconverting and the attack rate, i.e. the fraction of primary EBV infections that is accompanied by IM. We therefore aimed to provide these quantities indirectly, to obtain epidemiologically interpretable measures of the dynamics of IM occurrence to provide etiological clues.

Methods and findings

We used joint modeling of EBV prevalence and IM occurrence data to provide detailed sex- and age-specific EBV infection rates and IM attack rates and derivatives thereof for a target population of all Danes age 0–29 years in 2006–2011. We demonstrate for the first time that IM attack rates increase dramatically rather precisely in conjunction to typical ages of puberty onset. The shape of the seroconversion hazard rate for children and teenagers confirmed a priori expectations and underlined the importance of what happens at age 0–2 years. The cumulative risk of IM before age 30 years was 13.3% for males and 22.4% for females. IM is likely to become more common through delaying EBV infection in years to come.

Conclusions

The change in attack rate at typical ages of puberty onset suggests that the immunologic response to EBV drastically changes over a relatively short age-span. We speculate that these changes are an integrated part of normal sexual maturation. Our findings may inform further etiologic research into EBV-related diseases and vaccine design. Our methodology is applicable to the epidemiological study of any infectious agent that establishes a persistent infection in the host and the sequelae thereof.

Cytomegalovirus Seropositivity and Suicidal Behavior: A Mini-Review

Background and objectives: In recent years, a growing body of research has focused on identifying possible biological markers for suicidal behavior, including infective and immunological markers. In this paper, our aim was to review available evidence concerning the association between cytomegalovirus (CMV) infection and suicide. Materials and Methods: A systematic search according to the PRISMA statement was performed on Pubmed. After the screening procedure, we identified five relevant papers. Results: We found inconsistent evidence linking CMV infection and suicide, with some papers reporting an association between CMV seropositivity and suicidal behavior, and others not finding the association. Conclusions: With the evidence available presently, it is not possible to infer whether there is a correlation between suicide and CMV infection.

The global need and availability of blood products: a modelling study

BACKGROUND

Blood transfusions are an important resource of every health-care system, with often limited supply in low-income and middle-income countries; however, the degree of unmet need for blood transfusions is often unknown. We therefore aimed to estimate the blood transfusion need and supply at national level to determine gaps in transfusion services globally.

METHODS

We did a modelling study involving 195 countries and territories. We used blood component preparation data from 2011-13 to estimate blood availability for 180 (92%) of 195 countries from the WHO Global Status Report on Blood Safety and Availability. We calculated disease-specific transfusion needs per prevalent case for 20 causes in the USA using the National (Nationwide) Inpatient Sample dataset between the years 2000 and 2014, and the State Inpatient Databases between 2003 and 2007 from the Healthcare Cost and Utilization Project. Using prevalence estimates for the USA from the Global Burden of Disease (GBD) 2017 study, we estimated the ideal disease specific-transfusion rate as the lowest rate from the years 2000 to 2014. We applied this rate to GBD prevalence results for 195 countries to estimate transfusion needs. Unmet need was the difference between the estimated supply and need.

FINDINGS

In 2017, the global blood need was 304 711 244 (95% uncertainty interval [UI] 293 064 637-314 049 479) and the global blood supply was 272 270 243 (268 002 639-276 698 494) blood product units, with a need-to-supply ratio of 1·12 (95% UI 1·07-1·16). Of the 195 countries, 119 (61%) did not have sufficient blood supply to meet their need. Across these 119 countries, the unmet need totalled 102 359 632 (95% UI 93 381 710-111 360 725) blood product units, equal to 1849 (1687-2011) units per 100 000 population globally. Every country in central, eastern, and western sub-Saharan Africa, Oceania, and south Asia had insufficient blood to meet their needs.

INTERPRETATION

Our data suggest that the gap between need and supply is large in many low-income and middle-income countries, and reinforce that the WHO target of 10-20 donations per 1000 population is an underestimate for many countries. A continuous expansion and optimisation of national transfusion services and implementation of evidence-based strategies for blood availability is needed globally, as is more government support, financially, structurally, and through establishment of a regulatory oversight to ensure supply, quality, and safety in low-income and middle-income countries.

FUNDING

National Institutes of Health.

Herpes Simplex Virus Type 1 infection is associated with suicidal behavior and first registered psychiatric diagnosis in a healthy population

Increasing evidence shows that latent infections and inflammation is associated with cognitive and behavioral changes in humans. This case-control study investigates the association between Herpes Simplex Virus Type 1 (HSV-1) infection and C-reactive Protein (CRP) levels, and psychiatric disorders and suicidal behavior. Public health register data from 81,912 participants in the Danish Blood Donor Study, were reviewed to identify individuals registered with an ICD-10 code of any psychiatric diagnosis, or who had attempted or committed suicide. We found 1,504 psychiatric cases and 353 suicidal cases; for all cases, controls were frequency-matched by age and sex, resulting in 5,336 participants. Plasma samples were analyzed for IgG-class antibodies against HSV-1 and CRP. HSV-1 infection was associated with suicidal behavior (odds-ratio, 1.40; 95% confidence interval [CI] 1.11-1.77). Accounting for temporality, HSV-1 infection was associated with having first psychiatric disorder after the date of blood collection (incidence rate ration, 1.44; 95% CI, 1.05-1.95). No association between CRP and psychiatric disorders or suicidal behavior was found. The finding that HSV-1 was associated with suicidal behavior and first psychiatric disorder indicates that infection may play a role in the etiology and pathogenesis of suicidal behavior and development of psychiatric disorders.

Cohort description: The Danish Blood Donor Staphylococcus aureus Carriage Study

Purpose

Staphylococcus aureus carriage poses an increased risk of S. aureus infection. The aim of this study was to investigate the colonization of S. aureus among healthy individuals and to establish a prospective cohort and biobank for research in the health consequences of colonization.

Population and methods

The Danish Blood Donor S. aureus Carriage Study (DBDSaCS) was established in 2014. So far, a total of 6082 healthy participants have been included with nasal swabs and repeated swabs are performed at subsequent donations. Samples from the first 2217 participants were cultured using a two-step method to evaluate the effect of using enrichment broth. Furthermore, 262 participants were sampled from both the nares and the throat. All participants completed a questionnaire with self-reported health, anthropometric measurements, current smoking status, and physical activity. Plasma samples, nasal swab transport media, and S. aureus isolates were stored.

Results

The prevalence of S. aureus nasal colonization was 41%. The prevalence of colonization was higher in men (46%) than women (34%), lower for smokers, and decreased with increasing age (<25 years: 44% vs >55 years: 35%). In participants swabbed from the nose and throat, the prevalence of S. aureus colonization after enrichment was 55% with significantly higher prevalence in the throat (45%) than in the nose (40%). The use of an enrichment broth increased the proportion of S. aureus colonization.

Conclusion

We describe a large and growing cohort of healthy individuals established to investigate predictors for S. aureus carriage and the health consequences of carriage. Multiple projects using data from DBDSaCS linked with Danish health registers, biomarkers, and genetic markers are ongoing. Results will be published in the coming years.

Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders

BACKGROUND

Common infectious pathogens have been associated with psychiatric disorders, self-violence and risk-taking behavior.

METHODS

This case-control study reviews register data on 81,912 individuals from the Danish Blood Donor Study to identify individuals who have a psychiatric diagnosis (N = 2591), have attempted or committed suicide (N = 655), or have had traffic accidents (N = 2724). For all cases, controls were frequency matched by age and sex, resulting in 11,546 participants. Plasma samples were analyzed for immunoglobulin G (IgG) antibodies against Toxoplasma gondii and cytomegalovirus (CMV).

RESULTS

T. gondii was detected in 25·9% of the population and was associated with schizophrenia (odds ratio [OR], 1·47; 95% confidence interval [CI], 1·03-2·09). Accounting for temporality, with pathogen exposure preceding outcome, the association was even stronger (IRR, 2·78; 95% CI, 1·27-6·09). A very weak association between traffic accident and toxoplasmosis (OR, 1·11; 95% CI, 1·00-1·23, p = 0.054) was found. CMV was detected in 60·8% of the studied population and was associated with any psychiatric disorder (OR, 1·17; 95% CI, 1·06-1·29), but also with a smaller group of neurotic, stress-related, and somatoform disorders (OR, 1·27; 95% CI, 1·12-1·44), and with attempting or committing suicide (OR, 1·31; 95% CI, 1·10-1·56). Accounting for temporality, any psychiatric disorder (IRR, 1·37; 95% CI, 1·08-1·74) and mood disorders (IRR, 1·43; 95% CI, 1·01-2·04) were associated with exposure to CMV. No association between traffic accident and CMV (OR, 1·06; 95% CI, 0·97-1·17) was found.

CONCLUSIONS

This large-scale serological study is the first study to examine temporality of pathogen exposure and to provide evidence of a causal relationship between T. gondii and schizophrenia, and between CMV and any psychiatric disorder.

Sociodemographic and behavioral characteristics associated with blood donation in the United States: a population-based study

BACKGROUND

Contemporary population-based data on characteristics associated with blood donation in the United States (U.S.) are limited.

STUDY DESIGN AND METHODS

A cross-sectional analysis was performed among 28,739 persons aged 18 years and older who participated in the 2016 National Health Interview Survey, a household survey of the noninstitutionalized U.S. civilian population. Analyses were weighted and accounted for the complex survey design. Adjusted prevalence ratios (aPR) were estimated by multivariable log-binomial regression.

RESULTS

The percentage of individuals reporting a past-year history of blood donation was 5.7% (95% confidence interval [CI], 5.3%-6.1%) and was highest in the youngest age group (18-24 years, 8.4%). A past-year history of blood donation was more common in males compared to females (6.3% vs. 5.1%; aPR, 1.12 [95% CI, 0.99-1.27]) and those born in the U.S. compared to individuals born outside the U.S. (6.4% vs. 2.4%; aPR, 1.92 [95% CI, 1.49-2.47]). The percentage of individuals with a past-year history of blood donation was significantly lower in blacks (3.9%; aPR, 0.60 [95% CI, 0.47-0.75]) and Hispanics (3.0%; aPR, 0.63 [95% CI, 0.48-0.83]) in comparison to whites (6.9%). Being a college graduate, being employed, being physically active, and never being a cigarette smoker were factors positively associated with blood donation. The percentage of individuals with a past-year history of blood donation varied by geographic census region, with prevalence being higher in the Midwest (7.3%) and South (6.0%) compared to the Northeast (4.7%) and West (4.4%).

CONCLUSION

Continued differences in the blood donor population with reference to the U.S. population underscore the need to understand barriers or deterrents to blood donation. Evidence-based donor recruitment and related policies remain imperative to ensure that there is a sustainable blood supply.

DBDS Genomic Cohort, a prospective and comprehensive resource for integrative and temporal analysis of genetic, environmental and lifestyle factors affecting health of blood donors

PURPOSE

To establish a cohort that enables identification of genomic factors that influence human health and empower increased blood donor health and safe blood transfusions. Human health is complex and involves several factors, a major one being the genomic aspect. The genomic era has resulted in many consortia encompassing large samples sizes, which has proven successful for identifying genetic factors associated with specific traits. However, it remains a big challenge to establish large cohorts that facilitate studies of the interaction between genetic factors, environmental and life-style factors as these change over the course of life. A major obstacle to such endeavours is that it is difficult to revisit participants to retrieve additional information and obtain longitudinal, consecutive measurements.

PARTICIPANTS

Blood donors (n=110 000) have given consent to participate in the Danish Blood Donor Study. The study uses the infrastructure of the Danish blood banks.

FINDINGS TO DATE

The cohort comprises extensive phenotype data and whole genome genotyping data. Further, it is possible to retrieve additional phenotype data from national registries as well as from the donors at future visits, including consecutive measurements.

FUTURE PLANS

To provide new knowledge on factors influencing our health and thus provide a platform for studying the influence of genomic factors on human health, in particular the interaction between environmental and genetic factors.

Blood donation from 2006 to 2015 in Zhejiang Province, China: annual consecutive cross-sectional studies

OBJECTIVES

To describe the basic demographical characteristics of whole blood donors in Zhejiang Province, China, from 2006 to 2015 and to examine the trends in individual characteristics associated with blood donation and the relationship between weight and donation.

DESIGN

Cross-sectional study comparing characteristics of blood donors and annual donations for the period 2006 to 2015.

SETTING

Urban and rural communities in Zhejiang, China (11 cities, 89 districts or counties and 1379 townships).

PARTICIPANTS

3 226 571 volunteer blood donors.

OUTCOME MEASURES

Volume of each whole blood donation and donation frequency. All data were collected by trained staff and entered into a standardised electronic information system.

RESULTS

The number of blood donations generally trended up in Zhejiang Province from 2006 to 2015. Donors were predominately males aged 18 to 25 years, but this major donor age group shifted to the 26 to 45 year range by 2015. The rate of repeated blood donation was 30.8 per cent. The blood volume per donation concentrated in 200 mL and 400 mL categories has been gradually shifted to 300 mL and 400 mL. Approximately one-third of donors had a college education. The average weight of donors increased over time for both men and women. Both the blood volume of each donation and donation frequency were proportional to weight.

CONCLUSIONS

The trend of voluntary non-remunerated blood donation in Zhejiang province is positive. However, given the expected growth in demand for whole blood, more research is needed to increase both the donor pool and the rate of repeated donation. The relationship between body weight and blood donation warrants further study because while improving nutritional status is associated with higher average donation volume and more frequent donations, overnutrition may lead to poorer quality of donated blood. Blood donation may present a unique opportunity for health education and body weight management to monitor and improve population health.

Frequent blood donation and offspring scholastic attainment: an assessment of long-term consequences of prenatal iron deficiency

BACKGROUND

Due to physiological demands, children and premenopausal women are at risk of developing iron deficiency. In premenopausal women, the risk may be further increased by repeated whole blood donations. Short-term consequences of iron deficiency in infancy include impaired cognitive development and lower IQ scores. This prompts concern that maternal iron deficiency before or during pregnancy may have long-term consequences for the offspring, for example, by affecting scholastic attainment. The aim of this study was to evaluate if prepregnancy donation intensity is associated with offspring scholastic attainment measured as grade averages in standardized national written examinations in Denmark.

STUDY DESIGN AND METHODS

By using the Danish personal identification number as key, we obtained information on donation intensity before pregnancy, school grade, year of graduation, age of the students, students' sex, and parental length of education and income from various nationwide registers. Linear regression analyses were performed, with grade average as outcome and maternal donation status as explanatory variable (nondonor, n = 177,078; low-frequency donor, n = 4995 [one to five donations in the 3 years before pregnancy]; high-frequency donor, n = 414 [six or more donations in the 3 years before pregnancy), and further adjusted for the covariates listed above.

RESULTS

Adjusted normalized (mean, 0; standard deviation [SD], 1) test scores were statistically significantly higher for children of active female donors compared with children of nondonors (SD, 0.104; 95% confidence interval, 0.079-0.129). We observed no differences in scholastic attainment between children of low-frequency donors and high-frequency donors.

CONCLUSION

Prepregnancy donation intensity, as a proxy of iron stores, is not associated with subsequent offspring scholastic attainment.

Frequent blood donation and offspring birth weight-a next-generation association?

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.

Seroprevalence of Dengue and Zika Virus in Blood Donations: A Systematic Review

The presence of antibodies to Zika virus (ZIKV) and dengue virus (DENV) can be detected in blood donations. Donation-based surveillance provides an alternative strategy to estimate population prevalence by detecting antibodies that are circulating. To estimate population prevalence, we conducted a systematic review of literature on the seroprevalence of ZIKV and DENV antibodies in blood donations. We searched PubMed and Web of Science for studies that reported the seroprevalence of ZIKV and DENV in blood donations. The title and abstract of each study were screened by 2 reviewers simultaneously for possible inclusion, and the full text of selected studies was reviewed to ensure that they met inclusion criteria (used primary data collection, reported evidence of immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies in the blood supply, and included a representative sample of the total population). Immunoglobin test measuring levels of antibodies to IgM and IgG and number of positive cases were extracted from each study. No exclusions were made based on language or country. Our initial search identified 1890 studies after excluding duplicates, of which 76 were assessed for full text eligibility to ensure that they met our final inclusion criteria. There were 14 studies included in our review; 11 examined the seroprevalence of DENV, and 3 examined ZIKV. The highest seroprevalence by IgM was 2.82% for DENV and 0.53% for ZIKV. Our results indicate that the seroprevalence of ZIKV and DENV antibody presence in countries with active transmission is higher than reports by traditional surveillance in some countries. This finding is expected due to the large percentage of asymptomatic cases. The highest seroprevalence was observed for IgG, which can persist over long periods of time compared to IgM. Screening of blood donations may help supplement traditional surveillance measures, especially during outbreak settings.

Quantitative B-lymphocyte deficiency and increased TCRγδ T-lymphocytes in acute infectious spondylodiscitis

Acute infectious spondylodiscitis (AIS) is a serious infection of the spine with rising incidence and a mortality of 3–6%. The role of the immune system in AIS is largely unknown. We performed extensive B and T-lymphocyte phenotyping in patients with AIS at diagnosis and after treatment cessation. In this prospective multicentre study, flow cytometric analysis of T and B-lymphocyte subsets was performed in 35 patients at diagnosis and 3 months after treatment cessation. We additionally analysed levels of immunoglobulins and IgG subclasses, serum level and genetic variants of mannose-binding lectin, and somatic hypermutation. A total of 22 (61%) patients had B-lymphocytes below reference limit at baseline, persisting in 7 (30%) patients at follow-up. We found a lower proportion of CD19 + CD27 + IgD+ marginal zone B-lymphocytes and a higher proportion of γδ+ T-lymphocyte receptors compared with controls at both time points. Immunoglobulin levels were elevated at baseline compared to follow-up, and not associated with absolute B-lymphocyte count. In conclusion, a large proportion of AIS patients presented with profound B-lymphocyte deficiency, only partly reversible at follow-up. Identification of immune dysfunction related to AIS may allow for future targeted therapeutic interventions to restore host immunity.

Restless legs syndrome is associated with increased risk of migraine

Migraine and restless legs syndrome (RLS) are common disorders that are associated with a high level of individual suffering and major comorbidities. The aetiologies of the disorders are largely unknown, although both migraine and RLS have been linked to disturbances in the dopaminergic system and sleep issues, suggesting a relationship between the disorders. This study examines the association between RLS and migraine in a large population of otherwise healthy adults who are not taking medication. Cross-sectional study that included 20,938 participants enrolled in the Danish Blood Donor Study from 1 May 2015 to 1 February 2017. The study included complete information on migraines, the Cambridge-Hopkins RLS questionnaire, the Major Depression Inventory Scale, sex, age, body mass index (BMI), educational level, smoking status and alcohol consumption. Associations between RLS and migraine, with and without aura, were examined using multivariable logistic regression analysis. Among the participants, 4827 were self-reported migraine sufferers and 1091 were classified as suffering from RLS. Individuals with RLS had an increased risk of migraine compared to non-RLS sufferers, with an odds ratio (OR) = 1.52 (95% confidence interval: 1.33–1.73). For the investigated subtypes of migraine, this association was found to be OR = 1.55 (1.31–1.83) for migraines with aura and OR = 1.29 (1.09–1.52) for migraines without aura. We found a significantly increased occurrence of migraine in individuals with RLS. This risk was independent of sex, age, BMI, educational level, smoking status, alcohol consumption and depressive disorder. Our findings suggest that RLS and migraine may have a common aetiology.