The impact of running on gastrointestinal symptoms in patients with irritable bowel syndrome.

INTRODUCTION: Physical activity has been suggested to alleviate gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS); however, evidence is scarce. Running has become increasingly popular and may be beneficial for patients with IBS. To obtain more insight in the potential application of running as therapy, we aimed to explore the impact of running and its intensity on GI symptoms in patients with IBS. METHODS: Data from a large observational study in runners were used for this nested case-control study, which included 153 runners with IBS and 153 controls. All participants had completed a questionnaire on personal characteristics, running characteristics and GI symptoms. Regarding GI symptoms, the severity of nine symptoms was asked, both at rest and during and/or shortly (up to 3 h) after running. Each symptom could be scored on a scale from 0 (not bothersome) to 100 (very bothersome), resulting in a maximum total score of 900 points. KEY RESULTS: The prevalence and total severity score of GI symptoms were higher in runners with IBS than in controls, both at rest and during running. Among runners with IBS, the median (25th-75th percentile) total severity score during/after running was significantly lower than at rest (118 [50-200] vs. 150 [90-217]), while in controls no significant difference between running and rest was observed. Analyses stratified for running intensity revealed that the beneficial effect in runners with IBS was present when their most intensive training session was moderately intensive or intensive but not very intensive. CONCLUSIONS & INFERENCES: Running, particularly on moderate intensity, could have a beneficial effect on GI symptoms in patients with IBS.

Assessment of the Dutch Healthy Diet index 2015 in the Lifelines cohort study at baseline.

BACKGROUND: Dietary indices are useful measures to investigate associations between dietary intake and disease development. The Dutch Healthy Diet index 2015 (DHD2015-index), a measure of diet quality, assesses adherence to the 2015 Dutch dietary guidelines. We assessed the DHD2015-index in the Lifelines cohort study, and compared calculations from basic and detailed dietary intake data. This article replaces the retracted article that was published on 16 May 2022 [1]. METHODS: Dietary intake was assessed with a specially developed Food Frequency Questionnaire (FFQ) called Flower-FFQ, which consists of one main questionnaire (heart-FFQ), which asks for intakes of major food groups, and three complementary questionnaires (petal-FFQs), which ask for detailed information on food types within major food groups of the heart-FFQ. The DHD2015-index was assessed using data from the total Flower-FFQ (for 56,982 participants), and using data from the heart-FFQ only (for 129,030 participants). Agreement between the two indices was assessed with correlation and cross-classification. RESULTS: The median (25th-75th percentile) DHD2015-index score was 75 (65-85) for men and 81 (70-91) for women based on the Flower-FFQ, and 68 (58-77) for men and 73 (63-82) for women based on the heart-FFQ. The Kendall's tau-b correlation coefficient between the two scores was 0.67 for men and 0.66 for women. Cross-classification into quartiles of the DHD2015-index showed that 59-60% of participants were classified in the same quartile, 36-37% in the adjacent, and 4% in the non-adjacent. CONCLUSION: Dietary data from the Flower-FFQ provide the most optimal information to assess the DHD2015-index. However, the DHD2015-index from the heart-FFQ showed good agreement with the index from the Flower-FFQ of ranking participants according to diet quality, and can be used when the DHD2015 index from the Flower-FFQ is not available.

Efficacy and utility of a tool for both measurement of vitamin B6, B12, D, folate and iron status and assessment of diet quality in athletes.

NutriProfiel® is a tool to measure micronutrient status and to assess diet quality. It consists of measurement of micronutrient status in blood and a short food frequency questionnaire (FFQ) ('Eetscore-FFQ'). Based on the results, individuals receive a dietary advice. In this study, we evaluated the application of NutriProfiel in athletes ('NutriProfiel-Sport') by assessing the coverage of nutrient intake of the Eetscore-FFQ (part 1) and by evaluating athlete's dietary behaviour after using NutriProfiel-Sport and their satisfaction with this tool (part 2). For part 1, data of 419 athletes were used. We evaluated the coverage of nutrient intake of the Eetscore-FFQ using first and second MOMents (MOM1 and MOM2) sum scores of food items in the questionnaire. Forty-eight athletes were involved in part 2. They gave blood samples for micronutrient status measurement and were asked to complete the Eetscore-FFQ at baseline and after 3 months, as well as a questionnaire on their satisfaction with NutriProfiel-Sport. Results showed that for most nutrients, MOM1 and MOM2 scores were above 80 %, meaning that nutrient intake was sufficiently covered by the Eetscore-FFQ. No difference in diet quality was observed between baseline and after 3 months. Nevertheless, a majority of athletes reported the NutriProfiel-Sport results and advice as useful. On a scale from 0 to 10, NutriProfiel-Sport was graded with a mean (±sd) score of 7⋅6 (±0⋅8). In conclusion, NutriProfiel-Sport is a potential valuable and appreciated tool for athletes and the Eetscore-FFQ as part of this tool sufficiently covers nutrient intake in athletes.

Exercise-related abdominal complaints in a large cohort of runners: a survey with a particular focus on nutrition.

Objectives: Abdominal complaints (AC) during exercise are a common problem in runners. Nutrition is known to play a role in exercise-related AC, but information on the role of habitual dietary intake is limited. We assessed the prevalence of AC in a large cohort of runners, and investigated its association with potential risk factors, with a particular focus on nutritional factors in the habitual diet. Methods: A total of 1993 runners completed two online questionnaires: a general questionnaire on, among others, running habits and exercise-related AC and a Food Frequency Questionnaire. Runners with and without either upper AC (UAC) or lower AC (LAC) were compared regarding personal characteristics, running characteristics and habitual dietary intake. Results: 1139 runners (57%) reported AC during and/or up to 3 hours after running: 302 runners (15%) reported UAC, 1115 (56%) LAC and 278 (14%) both. In about one-third of runners with AC, these complaints negatively affected their running. Exercise-related AC were positively associated with female gender, younger age and more intense running. Most associations with nutritional factors were observed only for LAC in men, with a higher intake of energy, all macronutrients and grain products in men with LAC. In both men and women, a higher intake of tea and unhealthy choices were associated with AC. Conclusion: Exercise-related AC were quite prevalent, and in about one-third of the cases, AC impacted their running. Being female, having a younger age and running at higher intensity were positively associated with AC. Some aspects of the habitual diet were associated with AC. Most notable were positive associations for intake of fat, tea and unhealthy choices.

Factors associated with lower limb tendinopathy in a large cohort of runners: a survey with a particular focus on nutrition.

Objectives: Lower limb tendinopathy (LLT) is highly prevalent in runners. Treatment can be challenging, and knowledge of risk factors may be valuable to develop preventive or treatment interventions for LLT. The aims of this study were (1) to assess the prevalence of three common LLTs (Achilles tendinopathy (AT), patellar tendinopathy and plantar fasciopathy) in a large cohort of Dutch and Belgian runners and (2) to investigate its association with potential risk factors, with a particular focus on nutritional factors in the habitual diet. Methods: A total of 1993 runners were included in the study. They completed two online questionnaires: a general questionnaire on running habits and injuries and a Food Frequency Questionnaire. Runners with and without LLT were compared regarding personal characteristics, running characteristics and nutritional factors. Results: The point prevalence for the three LLTs was 6%; 33% of the runners reported LLT in the past and 35% had either a current or past LLT. AT was the most prevalent type of LLT, and prevalence rates for all types of LLT were higher in men than women. Positive associations with LLT were observed for age and running years (men and women), running level and running distance (men). No associations between LLT and nutritional factors were observed. Conclusion: One-third of this population of runners had ever experienced an LLT. These tendinopathies were associated with gender, age and running load, but not with nutritional factors.

Effect of a low carbohydrate, high fat diet versus a high carbohydrate diet on exercise efficiency and economy in recreational male athletes.

BACKGROUND: Exercise efficiency and economy are key determinants of endurance exercise performance. In this cross-over intervention trial, we investigated the effect of adherence to a low carbohydrate, high fat (LCHF) diet versus a high carbohydrate (HC) diet on gross efficiency (GE) and (OC) during exercise, both after 2 days and after 14 days of adherence. METHODS: Fourteen recreational male athletes followed a two-week LCHF diet (<10 energy % carbohydrate) and a two-week HC diet (>50 energy % carbohydrate), in random order, with a wash-out period of three weeks in between. After 2 and 14 days on each diet, the athletes performed a 90-minutes submaximal exercise session on a bicycle ergometer. Indirect calorimetry measurements were done after 60 minutes of exercise to calculate GE and OC. RESULTS: GE was significantly lower on the LCHF diet compared to the HC diet, after 2 days (17.6±1.9 vs. 18.8±1.2%, P=0.011, for the LCHF and HC diet respectively), not after 14 days. OC was significantly higher on the LCHF diet compared to the HC diet, after 2 days (1191±138 vs. 1087±72 mL O2/kCal, P=0.003, for the LCHF and HC diet respectively), and showed a strong tendency to remain higher after 14 days, P=0.018. CONCLUSIONS: Although LCHF diets are popular strategies to increase fat oxidation during exercise, adherence to a LCHF diet was associated with a lower exercise efficiency and economy compared to a HC diet.

Pitfalls in interpreting red blood cell parameters in elite high-altitude and sea-level athletes: A unique case series.

Standard routine hematological measurements are commonly used to investigate differences in blood parameters between high-altitude athletes (HAA) and sea-level athletes (SLA), and to monitor the effect of high-altitude training. In this way, red blood cell (RBC) parameters are usually expressed as relative parameters (concentration) rather than absolute parameters (total amount). In this unique case series of elite HAA and SLA, we describe how different ways of parameter expression can affect the interpretation of blood tests. In a group of 42 elite athletes, relative and absolute RBC parameters were compared between HAA and SLA. Absolute parameters were calculated by multiplying relative values with formula-based estimated blood volume (BV-e). Additionally, in two individual athletes, one HAA and one SLA, absolute parameters were also calculated with blood volume (BV) obtained by measurement with a dilution method (BV-m). In men, HAA had a significantly higher hemoglobin (Hb) concentration (+7.8%; p = 0.001) and total Hb mass per kg body weight (BW) (+12.0%; p = 0.002). When not corrected for BW, HAA had a lower, non-significant, total Hb mass (-7.8%; p = 0.055). In women, no significant differences between HLA and SLA were observed. The two individual athletes showed that, based on BV-m, in the HAA, total Hb mass and total Hb mass per kg BW were respectively 14.1% and 31.0% higher than in the SLA, whereas based on BV-e, in the HAA, total Hb mass was 20.8% lower and total Hb mass per kg BW was only 2.4% higher. Similar inconsistencies were observed for total RBC count. Thus, different ways of parameter expression, and different methods of BV assessment for the calculation of absolute parameter values, influence the interpretation of blood tests in athletes, which may lead to misinterpretation and incorrect conclusions.

Dietary Intake in the Lifelines Cohort Study: Baseline Results from the Flower Food Frequency Questionnaire among 59,982 Participants.

The role of nutrition in health and disease is well established. However, more research on this topic is needed to fill gaps in our current knowledge. The Lifelines cohort study, a large Dutch prospective cohort study, was established as a resource for international researchers, aiming to obtain insight into the aetiology of healthy ageing. The study started with 167,729 participants, covering three generations, aiming to follow them for thirty years. This article describes the habitual dietary intake, assessed using the Flower Food Frequency Questionnaire (FFQ), among Lifelines cohort study participants at baseline, stratified by sex and different categories of age, socioeconomic status (SES) and body mass index (BMI). A total of 59,982 adults (23,703 men and 36,279 women), who completed the Flower FFQ and reported plausible habitual dietary intake, were included in the analyses. Median daily energy intake was higher in men (2368 kcal) than in women (1848 kcal), as well as macronutrient intake. Energy and macronutrient intake decreased with increasing age and BMI categories; no differences were observed between SES categories. Intake of most micronutrients was higher in men than in women. Differences were observed between age categories, but not between SES and BMI categories. Food groups were consumed in different amounts by men and women; differences between age, SES and BMI categories were observed as well. The Lifelines cohort study provides extensive dietary intake data, which are generalisable to the general Dutch population. As such, highly valuable dietary intake data are available to study associations between dietary intake and the development of chronic diseases and healthy aging.

Impact of risk-dependent interventions on low haemoglobin deferral rates in whole blood donors.

BACKGROUND: Blood donors with a relatively low haemoglobin (Hb) level at their previous donation attempt have an increased risk of Hb deferral at the subsequent donation attempt. The aim of this study was to investigate whether the interventions prolongation of donation interval and/or a dietary advice decrease the Hb deferral rate. METHODS: 11 897 whole blood donors with Hb levels from below to 0·2 mmol/l above the cut-off level for donation received either no intervention, a prolongation of the donation interval to six or twelve months, a dietary advice, or both. Deferral rates for low Hb levels at the subsequent donation attempt were compared in the different intervention groups. Additionally, the effects of the interventions on Hb deferral risk and donor return for a subsequent donation attempt were analysed using generalized estimating equations. RESULTS: The Hb deferral rate was substantially lower in the group that received a prolongation of the donation interval to six months than in the Control Group (12·9% vs. 6·3% in men and 20·4% vs. 13·4% in women). However, the additional benefit of twelve over 6-month interval prolongation was small, and no benefit of a dietary advice showed up. On the other hand, receiving a dietary advice increased the likelihood of donor return for a subsequent donation attempt. CONCLUSION: Implementation of a protocol for the prolongation of donation intervals to six months for donors with Hb levels from below to slightly above the cut-off level for donation may reduce the deferral rate for low Hb levels while keeping donor lapse at a minimum.

Lifestyle behaviours, ethnicity and menstruation have little added value in prediction models for low haemoglobin deferral in whole blood donors.

OBJECTIVE: To investigate the added value of questionnaire-based predictors to existing prediction models for low haemoglobin (Hb) deferral in whole blood donors. BACKGROUND: Prediction models for Hb deferral risk can be applied in the invitation process of donors for a blood donation. Existing prediction models are based on routinely collected data. The model performance might be improved by the addition of predictive factors. METHODS: The added value of food consumption, smoking, physical activity, ethnicity and menstruation in the prediction of Hb deferral was assessed by comparing the existing models with extended models using the following measures: model X2 , concordance (c)-statistic and net reclassification improvement (NRI). RESULTS: Addition of one candidate predictor to the models did not substantially improve the model performance. Addition of multiple new candidate predictors significantly increased the model X2 (from 137 to 159 for men, and from 157 to 199 for women) and resulted in a non-significant increase of the c-statistic (from 0.85 to 0.87 for men, and from 0.78 to 0.81 for women). The NRI for men was 11.4% and for women 1.5% after addition of multiple predictors. CONCLUSION: Addition of lifestyle behaviours, ethnicity or menstruation to prediction models for low Hb deferral in whole blood donors improved the model performance, but not substantially. For easy use in practice, we do not recommend addition of the investigated predictors to the prediction models.

Reticulocyte hemoglobin content in a large sample of the general Dutch population and its relation to conventional iron status parameters.

BACKGROUND: No full consensus exists on which iron status parameters to use for iron status assessment. In this study, we assessed the usefulness of measurement of the hemoglobin content of reticulocytes (CHr) in the general population. METHODS: The following iron status parameters were assessed in 1024 adults: CHr, reticulocytes, hemoglobin (Hb), ferritin, serum iron, transferrin, transferrin saturation and mean corpuscular volume (MCV). Mean parameter values and correlation coefficients for CHr and other parameters were calculated. In addition, mean CHr levels in subgroups based on low and normal values of other iron status parameters were compared. RESULTS: Mean CHr values in men were 31.81 (SD = 1.50) pg and in women 31.32 (SD = 1.51) pg. A positive correlation was observed between CHr and Hb, ferritin, serum iron, transferrin saturation and MCV; a negative correlation was observed between CHr and transferrin. CHr levels were lower in subjects with low values of Hb, ferritin, serum iron and MCV compared to subjects with normal values for these parameters. CONCLUSION: Mean CHr values in this population were comparable to values reported in small healthy control groups. Associations with other parameters were in agreement with associations reported in literature. CHr measurement might have additional value in iron status assessment.

Generalizability of Dutch Prediction Models for Low Hemoglobin Deferral: A Study on External Validation and Updating in Swiss Whole Blood Donors.

BACKGROUND: Sex-specific prediction models for low hemoglobin (Hb) deferral have been developed in Dutch whole blood donors. In this study, we validated and updated the models in a cohort of Swiss whole blood donors. METHODS: Prospectively collected data from 53,772 Swiss whole blood donors were used. The predictive performance of the Dutch models was assessed in terms of calibration (agreement between predicted probabilities and observed frequencies) and discrimination (ability to discriminate between deferred and approved donors). The models were updated by revising the strength of the individual predictors in the models. RESULTS: A total of 1,065 men (3.3%) and 2,063 women (9.7%) were deferred from donation because of a low Hb level. Validation in Swiss donors demonstrated underestimation of predicted risks and significantly lower discriminative ability. The predictive effects of most predictors were weaker in Swiss donors. Updating the models increased the calibration for both men and women, and slightly increased the discriminative ability in men. CONCLUSION: Validation of the Dutch prediction models in Swiss whole blood donors showed lower, though adequate performance. In general, the Dutch prediction models can reliably predict the risk of Hb deferral, although for application in other countries small adaptations are necessary.

Hemoglobin assessment: precision and practicability evaluated in the Netherlands-the HAPPEN study.

BACKGROUND: Most donors do not like the invasive hemoglobin (Hb) measurement in fingerstick capillary samples. Alternative noninvasive devices have recently become available. In this study we assessed the precision and practicability of noninvasive devices and compared them with measurements in capillary and venous samples. STUDY DESIGN AND METHODS: A total of 2589 blood donors were included in the study. Hb levels were measured with the noninvasive devices NBM 200 or Haemospect and compared with values obtained with the invasive devices HemoCue 201 and HemoCue 301 and with venous values. Precision was evaluated in terms of sensitivity and specificity for detection of Hb levels below the cutoff level for donation, taking venous values as "reference values." RESULTS: Hb levels measured with both invasive and noninvasive devices differed significantly from venous measurements. Measurements with invasive devices correlated stronger with venous values and were more precise. Sensitivity ranged from 30.1% (HemoCue 201) to 3.5% (Haemospect) in men and from 36.6% (HemoCue 201) to 10.8% (Haemospect) in women. Specificity ranged from 99.8% (HemoCue 201) to 95.5% (Haemospect) in men and from 98.9% (HemoCue 201) to 94.6% (NBM 200) in women. Most donors preferred the noninvasive measurement. CONCLUSION: Measurements with invasive devices showed stronger correlation and better agreement with venous values than noninvasive devices. Sensitivity was low for all measurement devices, particularly the noninvasive ones. In terms of precision invasive measurement would be preferred for donor screening, although a majority of donors preferred the noninvasive measurement.

Minimum donation intervals should be reconsidered to decrease low hemoglobin deferral in whole blood donors: an observational study.

BACKGROUND: Most donor deferrals are due to low hemoglobin (Hb) levels. Previously measured Hb levels and donation intervals are known to be associated with Hb deferral. However, this relationship has never been quantified. In this study, we related the prevalence of Hb deferral to previously measured Hb levels and donation intervals. STUDY DESIGN AND METHODS: A total of 220,946 whole blood donors were categorized into groups based on their Hb level at the previous donation and on the time interval since the previous donation. For each group, the prevalence of Hb deferral was assessed. RESULTS: Hb deferral rates were higher when Hb levels at the previous donation were lower and donation intervals were shorter. With a donation interval shorter than 3 months, the prevalence of Hb deferral was below the 10% threshold only when the previous Hb level was at least 0.3 mmol/L above the cutoff level for donation. CONCLUSION: To maintain appropriate Hb levels, the minimum donation interval of 56 days is only sufficient for donors with Hb levels far above the cutoff level for donation. Protocols for minimum donation intervals should be reconsidered and may be based on previously measured Hb levels. This may result in a decrease of low Hb deferral.

Prediction of hemoglobin levels in whole blood donors: how to model donation history.

BACKGROUND: Recently, prediction models for hemoglobin (Hb) deferral risk have been developed. These models consider the previous Hb level plus change in Hb. Here, we investigated if the performance of models could be improved by considering more information on Hb level history. STUDY DESIGN AND METHODS: Data of 166,497 Dutch whole blood donors with sequential Hb measurements during 2 years (760,444 in total) were used to develop and internally validate three different regression models: two simple linear models with Hb level history included as 1) Hb at the previous visit plus change in Hb or 2) mean of all previous Hb levels and one mixed-effect model including measurements of all previous Hb levels. RESULTS: Thirteen percent of men and 21% of women were deferred because of a low Hb level at least once in 2 years. The simple linear models and the mixed-effect model performed similar, if an estimate of the random intercept of the mixed-effect model was used for individual donors to calculate the predicted Hb level. In men, the concordance (c)-statistic ranged from 0.87 to 0.89 and the R(2) ranged from 0.42 to 0.45. In women, the c-statistic ranged from 0.81 to 0.84. Values of R(2) in women were higher for the simple linear models than for the mixed-effect model, 0.37 and 0.40 versus 0.30, respectively. CONCLUSION: Previous Hb levels could be summarized with one predictor as the mean value of all previous Hb levels. This predictor can be used in an easy-to-use simple linear regression model.

External validation and updating of a Dutch prediction model for low hemoglobin deferral in Irish whole blood donors.

BACKGROUND: Recently, sex-specific prediction models for low hemoglobin (Hb) deferral have been developed in Dutch whole blood donors. In the present study, we validated and updated the models in a cohort of Irish whole blood donors. STUDY DESIGN AND METHODS: Prospectively collected data from 45,031 Irish whole blood donors were used. Hb cutoff levels for donation were approximately 0.35 mmol/L lower in Ireland than the Dutch cutoff levels (8.07 mmol/L vs. 8.40 mmol/L in men; 7.45 mmol/L vs. 7.80 mmol/L in women). The predictive performance of the models was assessed with calibration plots, calibration-in-the-large, and the concordance (c)-statistic. The models were updated by revising the strength of the individual predictors in the models. RESULTS: A total of 613 men (2.4%) and 1624 women (8.4%) were deferred from donation because of a low Hb level. Validation demonstrated underestimation of predicted risks and lower c-statistics for men and women compared to the Dutch cohort. The strength of most predictive factors, particularly previous Hb level, was lower in Irish donors. The updated models showed a c-statistic of 0.83 (95% confidence interval [CI], 0.81-0.84) for men and 0.76 (95% CI, 0.74-0.77) for women. CONCLUSION: The performance of Dutch prediction models for Hb deferral was limited when validated in Irish whole blood donors. Updating the models resulted in different predictor effects. This improved mainly the model calibration; the improvement in discrimination was small.

High prevalence of subclinical iron deficiency in whole blood donors not deferred for low hemoglobin.

BACKGROUND: Blood donors that meet the hemoglobin (Hb) criteria for donation may have undetected subclinical iron deficiency. The aim of this study was to assess the prevalence of subclinical iron deficiency in whole blood donors with Hb levels above cutoff levels for donation by measuring zinc protoporphyrin (ZPP) levels. In addition, prevalence rates based on other iron variables were assessed for comparison. STUDY DESIGN AND METHODS: The study population comprised 5280 Dutch whole blood donors, who passed the Hb criteria for donation. During donor screening, Hb levels were measured in capillary samples (finger prick), and venous blood samples were taken for measurements of ZPP and other iron variables. These variables included ferritin, transferrin saturation, soluble transferrin receptor (sTfR), hepcidin, red blood cell mean corpuscular volume (MCV), and mean cell Hb (MCH). RESULTS: With a ZPP cutoff level of at least 100 µmol/mol heme, subclinical iron deficiency was present in 6.9% of male donors and in 9.8% of female donors. Based on other iron variables, iron deficiency was also observed. Prevalence rates ranged from 4.8% (based on transferrin saturation) to 27.4% (based on hepcidin concentration) in men and from 5.6% (based on sTfR concentration) to 24.7% (based on hepcidin concentration) in women. CONCLUSION: Results from this study showed that subclinical iron deficiency is prevalent among blood donors that meet the Hb criteria for blood donation, based on ZPP levels and on other iron variables. This finding needs attention because these donors are at increased risk of developing iron deficiency affecting Hb formation and other cellular processes.

Zinc protoporphyrin levels have added value in the prediction of low hemoglobin deferral in whole blood donors.

BACKGROUND: Increased zinc protoporphyrin (ZPP) levels can indicate iron deficiency and may be predictive for low hemoglobin (Hb) deferral in blood donors. Prediction models for Hb deferral in whole blood donors have already been developed. In this study, we examined if addition of ZPP to these prediction models improves risk estimation of Hb deferral. STUDY DESIGN AND METHODS: This study included 4598 Dutch whole blood donors. Information on ZPP levels measured at the previous visit was added to the existing prediction models to estimate the risk of Hb deferral. Models were compared using the following measures: concordance (c)-statistic, continuous net reclassification improvement (NRI), and clinical net benefit (NB). RESULTS: Seventy-six male donors (2.9%) and 69 female donors (3.5%) were deferred because of a low Hb level. Previous ZPP level was associated with risk of Hb deferral (odds ratio for interquartile range of previous ZPP level, men 2.0 [95% confidence interval {CI}, 1.7-2.3]; women 2.2 [95% CI, 1.9-2.4]) in a multivariable risk model. Addition of ZPP into the models resulted in an increase of the c-statistic from 0.93 to 0.94 for men and from 0.80 to 0.85 for women. The added value of ZPP was confirmed by measures of clinical usefulness. NRI for men was 0.42, and for women, 0.56. At relevant threshold probabilities between 10 and 15%, NB was higher for models considering ZPP. CONCLUSION: This study shows that ZPP measurements obtained at the previous visit may have added value in the risk prediction of Hb deferral in whole blood donors.