Jordi Julvez

CREAL Center for Research in Environmental Epidemiology | CREAL · Child Health

The exposome, encompassing all external and internal environmental factors, provides a comprehensive understanding of the complex etiology of mental health. This study investigated the relationship between the external exposome during mid-adolescence and plasma proteomic biomarkers of mental health in 935 participants from the FinnTwin12 (Finland)...

Adolescence is a critical developmental period marked by significant physiological, psychological, and behavioural changes. Sex-specific biological factors can play a major role in their progression. Liquid chromatography – tandem mass spectrometry proteomic analysis was used to measure the plasma proteome abundances in 197 adolescents (11-16 years...

Telomere length (TL) is a biomarker linked to age-related diseases based on its sensitivity to oxidative DNA damage and inflammation. Methylmercury (MeHg) is a common pollutant in fish. It may induce oxidative stress leading to shorter TL. However, previous research showed contradictory results and dose-concentration dependencies and non-linear rel...

Background Social inequalities in child mental health are an important public health concern. Whilst previous studies have examined inequalities at a single time point, very few have used repeated measures outcome data to describe how these inequalities emerge. Our aims were to describe social inequalities in child internalising and externalising p...

Background: Epidemiological studies suggest that exposure to greenness during childhood may protect children from developing attention-deficit hyperactivity disorder (ADHD). Objective: We analyzed the effect of both prenatal (pregnancy) and early childhood (4-5-year follow-up) residential greenness exposure and green space availability on ADHD symp...

A balanced diet is relevant for neuropsychological functioning. We aimed to analyze the association between dietary patterns and neuropsychological outcomes in a sample of healthy adolescents of the Walnuts Smart Snack (WSS) cohort from Barcelona city. We performed principal components analysis (PCA) to determine dietary patterns in the adolescent...

The placenta plays a crucial role in protecting the fetus from environmental harm and supports the development of its brain. In fact, compromised placental function could predispose an individual to neurodevelopmental disorders. Placental epigenetic modifications, including DNA methylation, could be considered a proxy of placental function and thus...

Whether differences in lifestyle between co-twins are reflected in differences in their internal or external exposome profiles remains largely underexplored. We therefore investigated whether within-pair differences in lifestyle were associated with within-pair differences in exposome profiles across four domains: the external exposome, proteome, m...

Background Early childcare attendance may be related to children's internalizing and externalizing symptoms throughout childhood and young adolescence, however evidence from Europe is limited. We aimed to assess this association across multiple population-based birth cohorts of children recruited in different European countries. Methods Data come...

Impulsivity has been proposed to have an impact on glycemic dysregulation. However, it remains uncertain whether an unfavorable glycemic status could also contribute to an increase in impulsivity levels. This study aims to analyze associations of baseline and time‐varying glycemic status with 3‐year time‐varying impulsivity in older adults at high...

Background Growing evidence shows that dysregulated metabolic intrauterine environments can affect neurodevelopment, cognitive and behaviour in offspring. However, results of individual cohort studies have been inconsistent. We aimed to investigate the association between maternal diabetes before pregnancy and gestational diabetes mellitus (GDM) wi...

Background Early life environmental stressors play an important role in the development of multiple chronic disorders. Previous studies that used environmental risk scores (ERS) to assess the cumulative impact of environmental exposures on health are limited by the diversity of exposures included, especially for early life determinants. We used mac...

The objective is to investigate the relation between cord blood mercury concentrations and child neuro-behavioural functioning assessed longitudinally during childhood until pre-adolescence. Methods: The study involves mothers and their offspring engaged in the Spanish INMA birth cohort (n = 1147). Total mercury (THg) was determined in cord blood....

Nutrition is critical during pregnancy for the healthy growth of the developing infant, who is fully dependent on maternal dietary omega-3 supply for development. Fatty fish, a main dietary source of omega-3, is associated with decreased cardiovascular risk in adults. We conducted a longitudinal study based on a mother–offspring cohort as part of t...

DNA methylation (DNAm) is a developmentally dynamic epigenetic process, yet we still know little about how epigenetic effects on health outcomes vary over time; whether DNAm alterations during certain periods of development are more informative than others; and whether epigenetic timing effects differ by outcome. To address these questions, we appl...

Objective: We examined the association between Mediterranean diet and psychosocial functioning among high school students from Barcelona, Spain. Methods: This is a sample of healthy teenagers (11 to 16 years old) recruited during 2016–2017 from 12 high schools in Barcelona. The 622 participants responded the Mediterranean Diet Quality Index for Chi...

Purpose To test associations between children’s attendance of non-parental childcare prior to school entry and internalising and externalising symptoms throughout childhood and young adolescence. Methods Data come from six parent-offspring prospective birth cohort studies across five European countries within the EU Child Cohort Network. A two-stag...

Shortened telomere length (TL) has been associated with lower cognitive performance, different neurological diseases in adults, and certain neurodevelopmental disorders in children. However, the evidence about the association between TL and neuropsychological developmental outcomes in children from the general population is scarce. Therefore, this...

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 Energy balance‐related behaviours (EBRBs), that is, dietary intake, screen, outdoor play and sleep, tend to combine into ‘lifestyle patterns’, with potential synergistic influences on health. To date, studies addressing this theme mainly focused on school children and rarely accounted for sleep, with a cross‐country perspective. Objecti...

Background: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent and highly heritable neurodevelopmental disorder of major societal concern. Diagnosis can be challenging and there are large knowledge gaps regarding its etiology, though studies suggest an interplay of genetic and environmental factors involving epigenetic mechanisms. Micr...

Sleep problems and attention deficit hyperactivity disorder (ADHD) are interrelated during childhood and preadolescence. The objective of this work is assessing if sleep problems at ages 8–9 represent an alarm sign for presenting ADHD problems at ages 10–11 in three cohorts from INMA Study. Participants were 1244 children from Gipuzkoa, Sabadell, a...

Background Early-life environmental exposures are suspected to be involved in the development of chronic diseases later in life. Most studies conducted so far considered single or few exposures and single-health parameter. Our study aimed to identify a childhood general health score and assess its association with a wide range of pre- and post-nata...

Green spaces may have beneficial impacts on children's cognition. However, few studies explored the exposure to green spaces beyond residential areas, and their availability, accessibility and uses at the same time. The aim of the present study was to describe patterns of availability, accessibility, and uses of green spaces among primary school ch...

Background: Omega-3 fatty acids are critical for neuropsychological functioning. Adolescence is increasingly believed to entail brain vulnerability to dietary intake. The potential benefit on adolescent neurodevelopment of consuming walnuts, a source of omega-3 alpha-linolenic acid (ALA), remains unclear. Methods: We conducted a 6-month multi-schoo...

Background Early-life environmental exposures are suspected to be involved in the development of chronic diseases later in life. Most studies conducted so far considered single or few exposures and single-health parameter. Our study aimed to identify a childhood general health score and assess its association with a wide range of pre- and post-nata...

Cognitive health is a life-long concern affected by modifiable risk factors, including lifestyle choices, such as dietary intake, with serious implications for quality of life, morbidity, and mortality worldwide. In addition, nuts are a nutrient-dense food that contain a number of potentially neuroprotective components, including monounsaturated an...

Short sleep duration has been linked to adverse behavioral and cognitive outcomes in schoolchildren, but few studies examined this relation in preschoolers. We aimed to investigate the association between parent-reported sleep duration at 3.5 years and behavioral and cognitive outcomes at 5 years in European children. We used harmonized data from f...

Background Unbalanced iron homeostasis in pregnancy is associated with an increased risk of adverse birth and childhood health outcomes. DNA methylation has been suggested as a potential underlying mechanism linking environmental exposures such as micronutrient status during pregnancy with offspring health. We performed a meta-analysis on the assoc...

Evidence suggests that iron status may be linked to symptoms of childhood attention deficit/hyperactivity disorder (ADHD), but there is little data available on the relationship between iron status in pregnancy and the risk of developing ADHD. And the data that does exist is inconsistent. Our aim here is to assess the effect of maternal serum ferri...

There is existing evidence on how excessive screen exposure can be detrimental to cognitive health, and in recent years there has been an increase in the usage of mobile phones by adolescents. We aimed to examine the association between mobile phone screen exposure and cognitive function among a young healthy population. We carried out a cross-sect...

Ingested inorganic arsenic (iAs) is a human carcinogen that is also linked to other adverse health effects, such as respiratory outcomes. Yet, among populations consuming low-arsenic drinking water, the impact of iAs exposure on childhood respiratory health is still uncertain. For a Spanish child study cohort (INfancia y Medio Ambiente—INMA), low-a...

Background: Early-life vitamin D deficiency may impair immune system development contributing to allergy and asthma onset. Findings from prospective studies are inconsistent. Objective: To examine whether maternal and child vitamin D levels are associated with allergic and asthma-related symptoms throughout childhood in a Spanish birth cohort....

BACKGROUND: Inadequate sleep duration has been suggested as a chronic stressor associated with changes in telomere length (TL). This study aimed to explore the association between sleep duration and TL using the INMA birth cohort study data. METHODS: A total of 1014 children were included in this study (cross-sectional: 686; longitudinal: 872). Sle...

Omega-3 fatty acids are critical for brain function. Adolescence is increasingly believed to entail brain vulnerability to dietary intake. In contrast to the abundant research on the omega-3 docosahexaenoic acid (DHA) in cognition, research on DHA and attention in healthy adolescents is scarce. In addition, the role of alpha-linolenic acid (ALA), t...

Background Few studies have analyzed the associations between impulsivity and dietary patterns. Some of them have shown a cross-sectional inverse relationship between impulsivity and healthy diet scores, whereas others reported a positive association with unhealthy dietary assessments. We aimed to examine longitudinal associations of impulsivity tr...

Background & Aims Maternal ultra-processed food (UPF) consumption during pregnancy may adversely affect child development. Pregnancy sugar-sweetened beverage consumption (as a part of UPF) has been associated with child cognitive dysfunction in the general population, but the role of total UPF consumption during pregnancy in later child neuropsycho...

Background The age at onset of the association between poverty and poor health is not understood. Our hypothesis was that individuals from highest household income (HI), compared to those with lowest HI, will have increased fetal size in the second and third trimester and birth. Methods Second and third trimester fetal ultrasound measurements and...

(1) Background: Lutein and zeaxanthin (L&Z) are essential dietary nutrients that are a crucial component of the human macula, contributing to visual functioning. They easily cross the placental barrier, so that retinal deposition commences during foetal development. This study aims to assess associations between maternal L&Z intake during pregnancy...

Background: There are few studies that look at the intake of all types of omega-3 polyunsaturated fatty acids (n-3 PUFAs) during the different stages of pregnancy along with a long-term neuropsychological follow-up of the child. This study aims to explore the association between maternal n-3 PUFA intake during two periods of pregnancy and the chil...

Background: The EU LifeCycle Project was launched in 2017 to combine, harmonise, and analyse data from more than 250,000 participants across Europe and Australia, involving cohorts participating in the EU-funded LifeCycle Project. The purpose of this cohort description is to provide a detailed overview over the major measures within mental health d...

Background The recent evidence of the short-term impact of air pollution on youth cognitive functions is based primarily on observational studies. Objectives We conducted a randomized controlled trial to assess whether purifying the air of the classrooms produced short-term changes in attention processes of adolescents. Methods We recruited a tot...

Studies on factors that can influence attention in healthy adolescents are recent and focus on recurrent topics. Students' contribution to public health research often revolves around collecting data but rarely around creating data collection instruments. The ATENC!Ó project reunited secondary students and scientists to create a questionnaire inclu...

Background Environmental exposures in early life influence the development of behavioral outcomes in children, but research has not considered multiple exposures. We therefore aimed to investigate the impact of a broad spectrum of pre- and postnatal environmental exposures on child behavior. Methods and findings We used data from the HELIX (Human...

BACKGROUND: Type 2 diabetes was related with larger cognitive decline. However, other glycemic dysregulations showed inconsistent results. Our aim was to examine longitudinal associations between diabetes/glycemic status and cognitive function in older adults with metabolic syndrome. METHODS: We conducted a 2-year prospective cohort study (n=6,874)...

In the original article [...]

Background: Adolescence, when the most complex behaviors are refined to adult sophistication, represents a major window of opportunity and vulnerability for neuropsychological development. To support and protect this complex and active brain growth, different nutritional components considered essential need to be acquired from the diet. For instanc...

The potential etiological role of early acetaminophen exposure on Autism Spectrum Conditions (ASC) and Attention-Deficit/Hyperactivity Disorder (ADHD) is inconclusive. We aimed to study this association in a collaborative study of six European population-based birth/child cohorts. A total of 73,881 mother–child pairs were included in the study. Pre...

Epidemiological studies mostly focus on single environmental exposures. This study aims to systematically assess associations between a wide range of prenatal and childhood environmental exposures and cognition. The study sample included data of 1,298 mother-child pairs, children were 6-11 years-old, from six European birth cohorts. We measured 87...

Objective To investigate the association between maternal sleep duration (an important health indicator) and neonate birth weight. Methods The study included 2536 mother‐neonate pairs of a Spanish birth cohort (2004–2006, INMA project). The exposures were questionnaire‐based measures of sleep duration before and during pregnancy. The primary outco...

Background Studies looking at associations between environmental chemicals and child behaviour usually consider only one exposure or family of exposures. Objective This study explores associations between prenatal exposure to a wide range of environmental chemicals and child behaviour. Methods We studied 708 mother-child pairs from five European...

[This corrects the article DOI: 10.1016/j.pmedr.2016.08.013.].

Attention-deficit and hyperactivity disorder (ADHD) is a common childhood disorder with a substantial genetic component. However, the extent to which epigenetic mechanisms play a role in the etiology of the disorder is unknown. We performed epigenome-wide association studies (EWAS) within the Pregnancy And Childhood Epigenetics (PACE) Consortium to...

Ferritin status during prenatal brain development may influence the risk of attention deficit and hyperactivity disorder (ADHD) symptoms in childhood. We investigated the association of maternal ferritin in pregnancy and ADHD-like symptoms in offspring. A total of 1095 mother-child pairs from three birth cohorts of the INMA Project (Spain) were stu...

Background: We aimed to assess how lifestyle factors such as diet, sleep, screen viewing, and physical activity, individually, as well as in a combined score, were associated with neuropsychological development in pre-school age children. Methods: We conducted a cross-sectional study in 1650 children of 4 years of age, from the Environment and C...

Exposure to greenspace has been related to improved mental health, but the available evidence is limited and findings are heterogeneous across different areas. We aimed to evaluate the associations between residential exposure to greenspace and specific psychopathological and psychosomatic symptoms related to mental health among mothers from a Span...

(1) Background: Bullying affects a large number of children worldwide. This study has two objectives, to provide data on the prevalence of bullying in Spain, and to identify risk and protective factors associated with bullying. (2) Methods: Participants were 858 eleven-year-old children. Bullying was assessed using a short version of the Olweus Bul...