Frits Richard Rosendaal

Introduction: Estrogens play a large role in female and male physiology and are routinely determined in the clinical setting. For interpretation, distinct reference intervals (RIs) are applied for men, pre-, and postmenopausal women. Adipose tissue is a potent producer of estrogens and influences the circulating estrogen concentrations, although its impact on estrogen RIs is currently unknown. Method: We determined estradiol and estrone concentrations in 6671 middle-aged participants of a large cohort oversampled for persons with a Body Mass Index (BMI) ≥27 kg/m2. We investigated partitioning based on sex, age, menopausal status, and BMI by assessing the proportion of subgroups outside each limit of a shared 95% RI (ideally 2.5%) and calculating RIs for justified subgroups according to CLSI EP28-A3c. Results: As expected, the strongest partitioning factor was sex, followed by menopausal status for women. When using a shared RI for all BMI categories, 4.9% and 5.2% of values in men with obesity and 11.4% and 7.7% of values in postmenopausal women with obesity fell above the RI for estradiol and estrone, respectively. Within postmenopausal women, differences in the upper reference limit were found, being 138, 157, and 210 pmol/L for estradiol and 32, 41, and 74 pmol/L for estrone for normal weight, overweight, and obesity, respectively. Discussion: Laboratory professionals and clinicians should be aware that BMI affects estrogen concentrations to such an extent that it may influence clinical interpretation. Ideally, their RIs should be stratified by BMI category to reflect the increased estrogen concentrations associated with higher BMI.

Background and Aims: Residual pulmonary vascular obstruction (RPVO) defined as the persistence of thrombotic material within the pulmonary arteries several months after an acute pulmonary embolism (PE) is associated with an increased risk of severe complications, including recurrent events and chronic pulmonary hypertension. However, the genomic architecture underlying RPVO in unprovoked PE remains poorly understood, and this study aims to address this gap. Method: By leveraging genetic and imaging RPVO data from three independent cohorts totaling 586 unprovoked PE patients, we conducted a meta-analysis of genome wide association study (GWAS) of RPVO using a dedicated statistical method to handle the semi-continuous distribution of RPVO. The meta-GWAS was complemented by haplotype association analyses and transcriptome wide association studies as well as Mendelian Randomization (MR) approaches based on plasma metabolites and proteins. Results: Through meta-GWAS, we identified one locus, OSTN, associated with RPVO (lead variant rs59109356 associated with a ~2-fold increase of RPVO, p=3.92x10-8). A second locus, CCN4, previously reported to associate with pulmonary fibrosis, was also identified, with evidence of association approaching genome-wide significance (p=6.7x10-8). We also identified a common haplotype spanning over AHSG/HRG/KNG1 associated with a ~3-fold increase of RPVO (p=2.96x10-8). Using plasma protein-based MR, we demonstrated that one unit increase in genetically determined plasma levels of IL-1 R AcP encoding IL1RAP was associated with a 28% (p=1.32x10-6) reduction in RPVO. We also observed statistical evidence that the CCN4 (p=0.06) and IL1RAP (p=0.02) loci associate with the risk of PE recurrence in a sample of 1,617 unprovoked PE patients. Conclusions: By identifying novel molecular determinants of RPVO that map to loci involved in inflammatory pathways and vascular remodeling, our study provides evidence that inflammation is the predominant, and likely the key mechanism underlying RPVO, whereas impaired fibrinolysis appears to play a more limited role.

BACKGROUND: A high body mass index is an important risk factor for venous thromboembolism. However, high body mass index does not necessarily reflect an unhealthy body fat distribution. Therefore, we evaluated the association between the amount of visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue, and liver fat content with venous thromboembolism-associated coagulation parameters: plasma levels of factor (F) VIII, FIX, FXI, fibrinogen, and thrombin generation (endogenous thrombin potential and peak thrombin). METHODS: In 1759 participants of the NEO study (the Netherlands Epidemiology of Obesity), VAT and abdominal subcutaneous adipose tissue were assessed with magnetic resonance imaging, and liver fat with ¹ H-MR spectroscopy. Through linear regression, we examined cross-sectional associations between quartiles of body fat measures and coagulation parameters, stratified by sex and adjusted for relevant confounders. RESULTS: We found that the amount of VAT was associated with all coagulation parameters in a dose-response manner, with higher levels for individuals in quartile 4 versus 1, ranging between 5.2% (95% CI, −5.8 to 17.4) for FVIII in men and 21.0% (95% CI, 16.7–25.5) for FIX in women. In women, the amount of abdominal subcutaneous adipose tissue was associated with all coagulation parameters, with the highest percentual difference between quartile 4 versus 1 for endogenous thrombin potential 25.4% (95% CI, 13.7–38.4). Liver fat was mostly associated with higher FIX in both sexes, 13.2% (95% CI, 8.6–18.0) in men and 13.6% (95% CI, 10.0–17.4) in women. CONCLUSIONS: The strongest prothrombotic associations were found for VAT. Abdominal subcutaneous adipose tissue contributed only in women, though less strongly than VAT, indicating sex-specific associations. Liver fat was consistently associated with FIX. These findings underscore the importance of body fat distribution and sex in coagulation and thrombotic potential.

The Coronavirus Diseases (COVID-19) pandemic led to excess mortality in many countries, i.e., to more deaths than expected. Older individuals generally had higher absolute risks of excess death. The complex dynamics of infection, vaccination and excess mortality have not yet been captured in one comprehensive model. With nationwide and unselected data from Statistics Netherlands, we analyzed the impact of documented infection and vaccination on excess mortality during 2020 and 2021 in the Dutch population aged over 63 on 1 January 2020 ( n = 3,826,770) by incorporating relative survival into a multi-state model considering COVID-19 (re)infection, vaccination and death. Background mortality was based on the observed mortality in 2015–2019 per sex, age and month of the year. All analyses were performed for the total cohort as well as stratified per sex and age category. The absolute excess mortality in 2020–2021 was 0.34% (95% confidence interval 0.32–0.37), comprising 4.41% of the observed mortality. It was higher in men (except in the youngest age group) and older individuals. Excess mortality occurred mostly during the first four weeks after a positive COVID-19 test, but also thereafter. If infection occurred after vaccination, excess mortality was still observed, but considerably less than without prior vaccination. These patterns were observed in all groups. In conclusion, these analyses demonstrate the substantial impact of COVID-19 on excess mortality during and after acute SARS-CoV-2 infection in individuals aged over 63 years. Moreover, the results show a reduction of excess mortality after vaccination for all groups in this cohort.

Genetic predisposition and alcohol consumption are risk factors for increased blood pressure (BP), but their interactions influencing BP remain understudied. We conducted population-specific and cross-population meta-analyses of genome-wide gene-alcohol (GxAlc) interactions affecting BP in >1.1M individuals from multiple populations. We identified 46 GxAlc interaction loci for BP, including 21 from one-degree-of-freedom interaction tests (PGxAlc<5x10-8; or <0.05/Meff, Meff independent BP associations at P<10-5), and 25 from two-degree-of-freedom tests of main and interaction effects (PGxAlc<0.05/M2df, M2df independent 2df-associations at P2df<5x10-8), including 7 novel and 39 known BP loci. The 12q24 locus highlights the genetic effect of BRAP-rs11066001 on BP, being ~6 times larger in current drinkers than in non-drinkers. Gene prioritization with 46 GxAlc loci identified 15 genes with ≥3 lines of evidence (location, literature, druggability, functional/regulatory annotation, or pathway analyses). Several loci showed sex- and population-specific effects and revealed biological pathways of alcohol’s influence on BP, suggesting mechanisms underlying alcohol-induced hypertension.

Aims: We assessed whether symptomatic end-stage hip and knee osteoarthritis (OA) are associated with poorer sleep quality and to what extent pain mediates these associations. Methods: We included symptomatic end-stage hip- and knee OA participants from the Longitudinal Leiden Orthopaedics Outcomes of Osteo-arthritis Study (LOAS) and participants without OA from the Netherlands Epidemiology of Obesity (NEO) study. We assessed sleep with the Pittsburgh Sleep Quality Index (PSQI) and performed linear regression analyses to investigate the associations between OA and sleep and the potential mediating effects of pain-related sleep disturbances. Results: Overall, 54% of the 922 hip OA and 48% of the 870 knee OA patients reported poor sleep (total PSQI > 5), compared with 21% of the 1,165 participants without OA. Both hip and knee OA were associated with worse subjective sleep quality (adjusted difference: 0.37 points (95% CI 0.29 to 0.44) and 0.23 points (95% CI 0.15 to 0.32), respectively) and pain-related sleep disturbances (adjusted difference: 1.75 points (95% CI 1.64 to 1.86) and 1.50 points (95% CI 1.38 to 1.62), respectively). The association of hip and knee OA and worse subjective sleep quality was fully mediated by pain-related sleep disturbances (112% (95% CI 90 to 145) and 123% (95% CI 90 to 191), respectively). Conclusion: Symptomatic end-stage hip and knee OA are strongly associated with worse sleep quality, which is fully mediated by pain-related sleep disturbances. While the cross-sectional design limits causal inferences, these findings underscore the importance of improving both sleep quality and pain management strategies in symptomatic end-stage OA patients. Addressing sleep disturbances, which are often overlooked in clinical practice, could significantly enhance overall health and quality of life of patients with end-stage hip- or knee OA. Cite this article: Bone Jt Open 2026;7(3):348–356.

BACKGROUND: Recent evidence points to connections between HDLs (high-density lipoproteins), the coagulation system, and venous thromboembolism occurrence. However, uncertainty remains regarding the impact of specific HDL characteristics on the coagulation system. This study investigated associations between HDL characteristics and hemostatic parameters in a large middle-aged Dutch population. METHODS: Using baseline measurements from 6245 participants in NEO study (the Netherlands Epidemiology of Obesity), we performed adjusted linear regression analyses to estimate associations between 34 parameters of XLHDL (very large HDL), LHDL (large HDL), MHDL (medium HDL), and SHDL (small HDL) particles, as well as ApoA1 (apolipoprotein A1), quantified using a high-throughput ¹ H-nuclear magnetic resonance metabolomics platform, and coagulation parameters. These included coagulation factor (F) VIII, FIX, FXI, and fibrinogen, along with 5 parameters of the thrombin generation potential. In addition, the associations between HDL characteristics and parameters of platelet activation and endothelial glycocalyx health were tested in a subpopulation. RESULTS: Our findings revealed a particle size–dependent association between HDL parameters and coagulation parameters. Particularly, per 1-SD increase in the levels of components within XLHDL (very large HDL), we observed lower levels in FIX and FXI activities, endogenous thrombin potential, and peak height (median β [interquartile range], FIX: 3.26% [−3.50% to −3.18%]; FXI: −0.96% [−1.21% to −0.89%]; endogenous thrombin potential: −22.11 [−27.07 to −21.47] nmol/L·min; and peak height: −2.28 [−2.70 to −2.19] nmol/L), indicating an antithrombotic effect. In contrast, per 1-SD increase in the levels of components within MHDL and SHDL, we observed an increase in endogenous thrombin potential, peak height, and activities of FVIII, FIX, and FXI, indicating a prothrombotic effect. HDL characteristics were not associated with platelet activation parameters or with glycocalyx-related parameters. CONCLUSIONS: Our study provides evidence for a size-dependent relationship between HDL components and coagulation parameters. These findings contribute to a better understanding of the potential role of HDL in the pathogenesis of venous thromboembolism.

Background: It remains a challenge for GPs to identify all patients at increased risk of cardiovascular disease (CVD) in their practice, as performing cardiovascular risk assessment in every single patient is not feasible in routine practice. There is need for a simple tool to screen who is eligible for cardiovascular risk assessment and identify those at increased CVD risk. Aim: To investigate the value of measuring waist circumference in primary care by investigating: current recording practices of GPs; barriers and facilitators; and its contribution as a screening tool in the identification of patients at increased risk of CVD. Design and setting: A mixed-methods study was conducted in Dutch primary care. Method: We investigated the following three datasets: routine data from general practices ( n = 676 708 health records of adults); qualitative data from six focus groups ( n = 21 GPs); data from the Netherlands Epidemiology of Obesity (NEO) study ( n = 6671 middle-aged individuals). Results: Between 2012 and 2023, incidence rates of recorded waist circumference by GPs decreased from 47 to 3 per 1000 person-years. Barriers to GPs measuring waist circumference included discomfort, inability to measure it accurately, lack of measuring tape, and perceived uselessness. Facilitators included knowledge that increased waist circumference is a cardiovascular risk factor. In the NEO study population, after excluding patients already treated for the prevention of CVD ( n = 2407), 1731 patients were at increased risk of CVD ( n = 1113 intermediate risk, n = 618 high risk). Measuring waist circumference would identify 89% (993/1113) of those at intermediate and 93% (575/618) of those at high predicted cardiovascular risk. Conclusion: Waist circumference measurement may serve as a valuable screening tool to select patients eligible for cardiovascular risk assessment to identify those at increased risk of CVD in primary care. Since GPs currently rarely measure waist circumference, inclusion in guidelines and addressing identified barriers and facilitators is warranted.

Introduction Predicting bleeding in hemophilia A is difficult due to limitations of existing factor VIII (FVIII) activity assays, which correlate poorly with clinical bleeding tendency. Measurement of thrombin generation (TG) by calibrated automated thrombography (CT) may be an alternative to predict bleeding as it measures an individual’s complete plasma derived coagulation potential, rather than just focusing on one part of the coagulation cascade. However, lack of standardization limits its applicability. Objective To evaluate the ability of our standardized tissue factor (TF)/factor XI (FXI) a dual-activated thrombin generation assay (TGA) to assess TG across severe, moderate, and mild hemophilia A. Secondarily, we evaluate whether varying TG levels at similar FVIII concentrations translate to different clinical bleeding tendencies. Materials and Methods Plasma samples from 657 adult patients with hemophilia A of all severities included in the Hemophilia in the Netherlands 6 (HiN6) study were used. Samples were collected through standardized protocols from six Dutch hemophilia treatment centers, and stored in a centralized biobank. FVIII activity was centrally measured using one-stage assays. Thrombin generation was measured using our in-house TF/FXIa TGA protocol using 1 pm TF, 100 pm FXIa, and 30 μM phospholipids. Bleeding tendencies were analyzed based on patient questionnaires. Results The TF/FXIa dual-activated TGA protocol was able to measure thrombin generation across all severities of hemophilia A. Median peak heights (PH) were 119.5, 98.9, and 214.7 nM for severe, moderate, and mild, respectively. Moreover, the assay showed substantial variation in interindividual TG levels among patients with comparable FVIII activity levels (coefficient of variance of 99%, 83%, and 47% for severe, moderate, and mild hemophilia A, respectively). However, TG did not differentiate between patients with and without self-reported bleeding in this study. Conclusion The standardized TF/FXIa dual-activated TGA represents a tool for assessing individual coagulation potential in hemophilia A. More research is needed to further characterize the interindividual differences in thrombin generations at similar FVIII levels and possibly link these results to bleeding tendency.

Venous thromboembolism (VTE) is a frequent (annual incidence of 1-2 per 1000 individuals) and potentially life-threatening (case-fatality rate up to 10%) disease. VTE is associated with serious short-term and long-term complications, including a recurrence rate approaching 20% within 5 years. Anticoagulant therapy, the mainstay of VTE treatment, drastically reduces the risk of early VTE recurrence, but it exposes patients to a substantial risk of bleeding. We analyzed the genomic architecture of VTE recurrence using data from 6355 patients across 8 cohorts (including 1775 recurrences), enriched by subgroup analyses, according to sex and clinical manifestation of first VTE, which led to the identification of 28 molecular markers. Through genome-wide association studies, we identified 1 locus associated with VTE recurrence, GPR149/MME. Among all variants known to be associated with first VTE, KNG1, and FGG were associated with recurrence. Additionally, Mendelian randomization analyses identified 7 proteins as risk factors for recurrence: elevated plasma levels of coagulation factor XI, coagulation factor VIII, von Willebrand factor, histo-blood group ABO system transferase, and Golgi membrane protein 2; and decreased levels of proprotein convertase subtilisin/kexin 9 and pro–interleukin-16. Subgroup analyses revealed 18 molecular determinants associated with VTE recurrence, with notable differences between subgroups. For example, the exonic variant SLC4A1 p.Glu40Lys was significantly associated in patients who experienced pulmonary embolism but showed no effect in those with deep vein thrombosis. These findings emphasize the role of specific genetic loci and protein pathways in influencing VTE recurrence and provide valuable insights into potential therapeutic targets. Further research is needed to clarify the biological mechanisms driving these associations.