Tim S Nawrot

• Professor (Full) at Hasselt University

Objective To explore the association between telomere length (TL) and attention deficit hyperactivity disorder (ADHD) symptoms in children at 6–12 years. Method Data from 1,759 children belonging to the HELIX project cohorts and the Asturias, Gipuzkoa and Valencia cohorts of INMA project were included. TL was determined by blood sample using a PCR...

Background Telomere length is an important indicator of biological age and a complex multi-factor trait. To date, the telomere interactome for comprehending the high-dimensional biological aspects linked to telomere regulation during childhood remains unexplored. Here we describe the multi-omics signatures associated with childhood telomere length....

This study evaluated the association between age at first full-term pregnancy (FFTP) and mammographic breast density (MBD) in postmenopausal women. A total of 1,034 women, ages 50 to 69 years, were recruited from the Flemish (Belgium) population–based breast cancer screening program. Participants completed a questionnaire on lifestyle and reproduct...

Prognostic significance of the timing in the cardiac cycle of the first (TP1) and second (TP2) systolic peak of the central aortic pulse wave is ill‐defined. Incidence rates and standardized multivariable‐adjusted hazard ratios (HRs) of adverse health outcomes associated with TP1 and TP2, estimated by the SphygmoCor software, were assessed in the I...

Telomere length (TL) has gained attention as a biomarker for longevity and productivity in dairy cattle. This study explored the association between neonatal TL in Holstein calves and lifetime parameters (lifespan, milk production, and reproduction). Blood samples were collected from 210 calves (≤10d old) across four dairy farms in Flanders, Belgiu...

Exposure to environmental pollutants can disrupt normal immune system development and functioning, which may lead to long-term health consequences. However, the impact of exposure to chemical mixtures on the adolescent immune system has not been extensively studied. White blood cells (leukocytes) are part of the immune system, and an elevated leuko...

Telomere length (TL) is a recognized biomarker for ageing in multiple species. In dairy cattle, the transition period is considered a very stressful period. We hypothesized that TL shortens during this period. Holstein cows (n = 61) were followed during the transition period. Blood and milk samples were collected at − 7, 3, 6, 9, 21d relative to ca...

Blacks are more prone to salt‐sensitive hypertension than Whites. This cross‐sectional analysis of a multi‐ethnic cohort aimed to search for proteins potentially involved in the susceptibility to salt sensitivity, hypertension, and hypertension‐related complications. The study included individuals enrolled in African Prospective Study on the Early...

Background Evidence is accumulating that elevated levels of particulate air pollution, including black carbon, have been linked to gastrointestinal disorders and a lower intestinal bacterial richness and diversity. One of the hypothesized underlying mechanisms is the absorption of air pollution-related particles from the gastrointestinal tract. Me...

Objectives Greater vulnerability of Black vs. White individuals to cardiovascular disease (CVD) and chronic kidney disease (CKD) is well charted in the United States, but studies involving sub-Saharan blacks are scarce. Methods Baseline data (2021–2024) were collected in 168 sub-Saharan Blacks and 93 European Whites in an ongoing clinical trial (N...

Background Lead is a widespread environmental toxicant. However, there is currently no consensus whether low-level lead exposure raises blood pressure (BP) or induces kidney dysfunction. Purpose The Study for Promotion of Health in Recycling Lead (SPHERL) assessed the BP and renal function (RF) responses for up to six years in the workers without...

Background While the relation of salt intake with blood pressure (BP) is linear, it is U-shaped for mortality and cardiovascular disease (CVD). Purpose This individual-participant meta-analysis explored whether the relation of hypertension, death or CVD with 24 h urinary sodium excretion (UVNA) or sodium-to-potassium (UNAK) ratio was modified by b...

Background Growing evidence points to an association between ambient air pollution and decreased human reproductive potential. The aim of this study was to systematically review the association between air pollutants and female ovarian reserve. Methods The literature was searched in six electronic databases through August 2023. Screening of the 75...

Background Micro- and nanoplastics (MNPs) are emerging pollutants of concern with ubiquitous presence in global ecosystems. MNPs pose potential implications for human health; however, the health impacts of MNP exposures are not yet understood. Recent evidence suggests that MNPs can cross the placental barrier, underlying the urgent need to understa...

Background Growing evidence indicates an association between ambient air pollution and decreased human reproductive potential. This study aims to systematically review the association between air pollutants and female ovarian reserve. Methods The literature was searched in six electronic databases through June 2024. Screening the 136 articles retr...

None of the spironolactone trials in heart failure (HF) assessed the blood pressure (BP) responses to exercise, while conflicting results were reported for exercise capacity. In the HOMAGE trial, 527 patients at increased HF risk were randomized to usual treatment with or without spironolactone (25–50 mg/day). The current substudy included 113 cont...

Cystic fibrosis (CF) is characterized by chronic airway inflammation and premature aging. The link with leukocyte telomere length (LTL) as a marker of biological aging is unclear. We studied disease severity and LTL in 168 CF patients of which 85 patients had a second retrospective LTL assessment. A higher FEV1 was associated with longer LTL, with...

Background Nephron number variability may hold significance in the Developmental Origins of Health and Disease hypothesis. We explore the impact of gestational particulate pollution exposure on cord blood cystatin C, a marker for glomerular function, as an indicator for glomerular health at birth. Methods From February 2010 onwards, the ENVIRONAGE...

Aims Few randomized trials assessed the changes over time in the chronotropic heart rate (HR) reactivity (CHR), HR recovery (HRR) and exercise endurance (EE) in response to the incremental shuttle walk test (ISWT). We addressed this issue by analysing the open HOMAGE (Heart OMics in Aging) trial. Methods In HOMAGE, 527 patients prone to heart fail...

Background: Evidence regarding the effectiveness of prenatal nutritional supplements has mainly considered anthropometric pregnancy outcomes. The effect on markers of health and disease, such as offspring telomere length (TL) and mitochondrial DNA content (mtDNAc) is unknown. Objectives: We assessed the efficacy of maternal multiple micronutrient (...

Pulse pressure amplification (PPA) is the brachial-to-aortic pulse pressure ratio and decreases with age and cardiovascular risk factors. This individual-participant meta-analysis of population studies aimed to define an outcome-driven threshold for PPA. Incidence rates and standardized multivariable-adjusted hazard ratios (HRs) of cardiovascular a...

Micro- and nanoplastics (MNPs) are ubiquitous environmental pollutants representing a concern for human health. MNPs have been detected in human placentas, indicating that during pregnancy maternal exposure may lead to placental transfer and foetal exposure, with potential for adverse effects on early-life development. However, a comprehensive risk...

BACKGROUND Micro- and nanoplastics (MNPs) are emerging pollutants of concern with ubiquitous presence in global ecosystems. MNPs pose potential implications for human health; however, the health impacts of MNP exposures are not yet understood. Recent evidence suggests that MNPs can cross the placental barrier, underlying the urgent need to understa...

Telomere length (TL), a marker of cellular aging, has been studied in adults with regard to its connection to cognitive function. However, little is known about the association between TL and cognitive development in children. This study investigated the interplay between TL and cognitive functioning in 283 Belgian children aged four to six years o...

Background Mitochondrial heteroplasmy reflects genetic diversity within individuals due to the presence of varying mitochondrial DNA (mtDNA) sequences, possibly affecting mitochondrial function and energy production in cells. Rapid growth during early childhood is a critical development with long-term implications for health and well-being. In this...

Importance The cord blood proteome, a repository of proteins derived from both mother and fetus, might offer valuable insights into the physiological and pathological state of the fetus. However, its association with birth weight and growth trajectories early in life remains unexplored. Objective To identify cord blood proteins associated with bir...

Objective Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine understanding of the antifibrotic action of spironolactone. Methods In this substudy (n=290) to the Heart ‘Omics’ in Age...

Importance Ambient air pollution is a worldwide problem, not only related to respiratory and cardiovascular diseases but also to neurodegenerative disorders. Different pathways on how air pollutants could affect the brain are already known, but direct evidence of the presence of ambient particles (or nanoparticles) in the human adult brain is limit...

Objectives We undertook time-stratified analyses of the National Health and Nutrition Examination Survey in the US to assess time trends (1999–2020) in the associations of blood lead (BL) with blood pressure, mortality, the BL-associated population attributable fraction (PAF). Methods Vital status of participants, 20–79 years old at enrolment, was...

BACKGROUND Wave separation analysis enables individualized evaluation of the aortic pulse wave components. Previous studies focused on the pressure height with overall positive but differing results. In the present analysis, we assessed the associations of the pressure of forward and backward (P for and P ref ) pulse waves with prospective cardiova...

Background Immunosuppressive treatment in heart transplant (HTx) recipient causes osteoporosis. The urinary proteomic profile (UPP) includes peptide fragments derived from the bone extracellular matrix. Study aims were to develop and validate a multidimensional UPP biomarker for osteoporosis in HTx patients from single sequenced urinary peptides id...

Background In low- and middle-income countries countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection. Methods We conducted a case-control study among 1,277 HIV-infected adults in...

Importance Bone mass accrual is influenced by environmental and lifestyle factors. Targeted interventions at the early stages of life might decrease fracture and/or osteoporosis risk later in life. Objective To investigate whether early-life exposure to residential surrounding green space is associated with a change in bone mineral density in youn...

Background: A recently developed urinary peptidomics biological aging clock can be used to study accelerated human aging. From 1990 to 2019, exposure to airborne particulate matter (PM) became the leading environmental risk factor worldwide. Objectives: This study investigated whether air pollution exposure is associated with accelerated urinary...

Maternal educational attainment (MEA) shapes offspring health through multiple potential pathways. Differential DNA methylation may provide a mechanistic understanding of these long-term associations. We aimed to quantify the associations of MEA with offspring DNA methylation levels at birth, in childhood and in adolescence. Using 37 studies from h...

Background: Evidence regarding the effectiveness of prenatal nutritional supplements has mainly considered anthropometric pregnancy outcomes. The effect on markers of health and disease, such as offspring telomere length (TL) and mitochondrial DNA content (mtDNAc) is unknown. Objectives: We assessed the efficacy of maternal multiple micronutrient (...

FLEXiGUT - the Flemish exposome project- is the first large-scale study focused on investigating the importance of the exposome in the development and progression of chronic low-grade gut inflammation both in children and adults. To this end, we combine exposure records and high-throughput omics technologies with epidemiological studies. We investi...

The Study for Promotion of Health in Recycling Lead (SPHERL) assessed the blood pressure (BP) and renal function (RF) responses for up to 6 years in the workers without previous occupational lead exposure. BP was the average of five consecutive readings and the estimated glomerular filtration rate was derived from serum creatinine (eGFRcrt) and cys...

Background Particulate matter (PM) is a major environmental health concern and there is growing evidence that early exposure to PM can have adverse effects on neurobehavioral development in children, including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). In this study, we hypothesized that prenatal PM2.5 expos...

This study examined the association between folic acid supplements (FAs) during different periods of pregnancy and offspring telomere length (TL) at age four in 666 children from the INMA study. FAs were self-reported using food-structured questionnaires during three periods of pregnancy (the first three months of pregnancy, from month fourth onwar...

Background In developing countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection. Methods We conducted a case-control study among 1,277 HIV-infected adults in Bukavu, eastern Democra...

Background: Seasonal variations in environmental exposures at birth or during gestation are associated with numerous adult traits and health outcomes later in life. Whether DNA methylation (DNAm) plays a role in the molecular mechanisms underlying the associations between birth season and lifelong phenotypes remains unclear. Methods: We carried...

Knowledge of whether prenatal exposure to ambient air pollution disrupts steroidogenesis is currently lacking. We investigated the association between prenatal ambient air pollution and highly accurate measurements of cord blood steroid hormones from the androgenic pathway. This study included 397 newborns born between the years 2010 and 2015 from...

Background Transfer of the trace metal cobalt (Co) from mother to foetus has not been documented in populations with high environmental exposure to Co, as is the case in the African Copperbelt mining region. We analysed data obtained from 246 mother-infant pairs included (at delivery) in a previously published case-control study on birth defects,...

Early childhood is a critical period for both immune and neural development. and interactions between the immune system and neurons are believed to help regulate synaptic plasticity, which is critical for learning. However, it’s unclear how exposure to microbes within indoor dust might influence brain function in children. To learn more, researcher...

Evidence indicates a link between exposure to ambient air pollution and decreased female fertility. The ability of air pollution particles to reach human ovarian tissue and follicles containing the oocytes in various maturation stages has not been studied before. Particulate translocation might be an essential step in explaining reproductive toxici...

Background: Aortic pulse wave velocity (PWV) predicts cardiovascular events (CVEs) and total mortality (TM), but previous studies proposing actionable PWV thresholds have limited generalizability. This individual-participant meta-analysis is aimed at defining, testing calibration, and validating an outcome-driven threshold for PWV, using 2 populat...

Lead is an environmental hazard that should be addressed worldwide. Over time, human lead exposure in the western world has fallen drastically to levels comparable to those in humans living in the pre-industrial era, who were mainly exposed to natural sources of lead. To re-evaluate the health risks possibly associated with present-day lead exposur...

Background Air pollutant exposure is one of the major risk factors for aggravation of respiratory diseases. We investigated whether exposure to air pollution and accumulated black carbon particles in blood were associated with COVID-19 disease severity, including the risk for intensive care and duration of hospitalisation. Methods From May 2020 un...

BACKGROUND: Aortic pulse wave velocity (PWV) predicts cardiovascular events (CVE) and total mortality (TM), but previous studies proposing actionable PWV thresholds have limited generalizability. This individual-participant meta-analysis is aimed at defining, testing calibration, and validating an outcome-driven threshold for PWV, using two populat...

Purpose of Review A healthy indigenous intestinal microbiome is essential for human health. Well-established gut microbiome determinants only explain 16% of the inter-individual variation in gut microbiome composition. Recent studies have focused on green space as a potential determinant of the intestinal microbiome. We systematically summarize all...

Background: While biological age in adults is often understood as representing general health and resilience, the conceptual interpretation of accelerated biological age in children and its relationship to development remains unclear. We aimed to clarify the relationship of accelerated biological age, assessed through two established biological age...

While biological age in adults is often understood as representing general health and resilience, the conceptual interpretation of accelerated biological age in children and its relationship to development remains unclear. We aimed to clarify the relationship of accelerated biological age, assessed through two established biological age indicators,...

While biological age in adults is often understood as representing general health and resilience, the conceptual interpretation of accelerated biological age in children and its relationship to development remains unclear. We aimed to clarify the relationship of accelerated biological age, assessed through two established biological age indicators,...

While biological age in adults is often understood as representing general health and resilience, the conceptual interpretation of accelerated biological age in children and its relationship to development remains unclear. We aimed to clarify the relationship of accelerated biological age, assessed through two established biological age indicators,...

Background: Ultrafine particles, including black carbon (BC), can reach the systemic circulation and therefore may distribute to distant organs upon inhalation. The kidneys may be particularly vulnerable to the adverse effects of BC exposure due to their filtration function. Objectives: We hypothesized that BC particles reach the kidneys via the sy...

Background Airborne pollution particles have been shown to translocate from the mother’s lung to the fetal circulation, but their distribution and internal placental-fetal tissue load remain poorly explored. Here, we investigated the placental-fetal load and distribution of diesel engine exhaust particles during gestation under controlled exposure...

High blood pressure (BP) and type-2 diabetes (T2DM) are forerunners of chronic kidney disease and left ventricular dysfunction. Home BP telemonitoring (HTM) and urinary peptidomic profiling (UPP) are technologies enabling risk stratification and personalized prevention. UPRIGHT-HTM (NCT04299529) is an investigator-initiated, multicenter, open-label...

With urinary proteomics profiling (UPP) as exemplary omics technology, this review describes a workflow for the analysis of omics data in large study populations. The proposed workflow includes: (i) planning omics studies and sample size considerations; (ii) preparing the data for analysis; (iii) preprocessing the UPP data; (iv) the basic statistic...

Background: Although the relation of salt intake with blood pressure (BP) is linear, it is U-shaped for mortality and cardiovascular disease (CVD). This individual-participant meta-analysis explored whether the relation of hypertension, death or CVD with 24-h urinary sodium excretion (UVNA) or sodium-to-potassium (UNAK) ratio was modified by birth...

While mammographic breast density (MBD) is a well-established independent risk factor for breast cancer and age at first full-term pregnancy (FFTP) has been identified as a protective factor, there are very few high-quality studies that address the relationship between these two variables. The goal of this work was to generate a systematic review o...

BACKGROUND: Mineralocorticoid receptor (MR) activation induces fibrosis. Urinary proteomic profiling (UPP) detects thousands of sequenced peptides, mainly derived from collagen. No previous study applied UPP to generate insights in the antifibrotic actions of MR antagonism. METHODS: Based on urine sample availability, subsets of the open HOMAGE tri...

Background and aim: Parabens are widely used as antimicrobial preservatives in personal care products. Studies investigating obesogenic or cardiovascular effects of parabens show discordant results, while data on preschool children are lacking. Paraben exposure during early childhood could have profound cardiometabolic effects later in life. Meth...

Background Cognitive performances of schoolchildren have been adversely associated with both recent and chronic exposure to ambient air pollution at the residence. In addition, growing evidence indicates that exposure to green space is associated with a wide range of health benefits. Therefore, we aimed to investigate if surrounding green space at...

Telomere length is associated with longevity and survival in multiple species. In human population-based studies, multiple prenatal factors have been described to be associated with a newborn's telomere length. In the present study, we measured relative leukocyte telomere length in 210 Holstein Friesian heifers, within the first ten days of life. T...

Sedentary behaviour (SB) may be related to telomere length (TL) attrition due to a possible pro-inflammatory effect. This study examined the association between parent-reported sedentary behaviour (SB) and leukocyte TL at the age of 4 and telomere tracking from 4 to 8 years. In the Spanish birth cohort Infancia y Medio Ambiente (INMA) project, we a...

A healthy indigenous intestinal microbiome is indispensable for intra- and extra-intestinal human health. Since well-established factors such as diet and antibiotic use only explain 16 % of the inter-individual variation in gut microbiome composition, recent studies have focused on the association between ambient particulate air pollution and the i...

Background Globally, the rapid increase of obesity is reaching alarming proportions. A new approach to reduce obesity and its comorbidities involves tackling the built environment. Environmental influences seem to play an important role, but the environmental influences in early life on adult body composition have not been thoroughly investigated....

Maternal resilience and social inequality during the perinatal period: possible prevention and early intervention strategies Maternal mental wellbeing during the first 1,000 days (from conception until the first years of life) is of crucial importance for the development and health later in life. In part 1 of this article, the current state of know...

Background: While biological age in adults is often understood as representing general health and resilience, the conceptual interpretation of accelerated biological age in children and its relationship to development remains unclear. We aimed to clarify the relationship of accelerated biological age, assessed through telomere length and three omic...

Maternal resilience and social inequality during the perinatal period: influence of underlying biological mechanisms and potential intervention strategies The first 1,000 days (from conception until the second year of life) represent a crucial stage of life. It is a sensitive period for the development and health of the child, as well as for the we...

Background Rapid postnatal growth may result from exposure in utero or early life to adverse conditions and has been associated with diseases later in life and, in particular, with childhood obesity. DNA methylation, interfacing early-life exposures and subsequent diseases, is a possible mechanism underlying early-life programming. Methods Here, a...

Background Childhood cognitive development depends on neuroimmune interactions. Immunomodulation by early-life microbial exposure may influence neuropsychological function. In this study, we investigate the association between residential indoor microbiota and cognition and behavior among preschoolers. Results Indoor-settled dust bacterial and fun...

Lead exposure causing hypertension is the mechanism commonly assumed to set off premature death and cardiovascular complications. However, at current exposure levels in the developed world, the link between hypertension and lead remains unproven. In the Study for Promotion of Health in Recycling Lead (NCT02243904), we recorded the 2 year responses...

Abstract Background The aetiology of chronic rhinosinusitis (CRS) is multifactorial with a complex interplay between environmental, microbial endogenous and genetic factors. The impact of outdoor air pollution on prevalence or severity of CRS remains largely unknown. Methods Real-life geolocation data (2017–2018, Belgium) from 278 CRS patients (257...

Mitochondria are sensitive to oxidative stress, which can be caused by traffic-related air pollution. Placental mitochondrial DNA (mtDNA) mutations have been previously linked with air pollution. However, the relationship between prenatal air pollution and cord-blood mtDNA mutations has been poorly understood. Therefore, we hypothesized that prenat...