Human Early Life Exposome (HELIX) study: a European population-based exposome cohort

Abstract

PurposeEssential to exposome research is the collection of data on many environmental exposures from different domains in the same subjects. The aim of the Human Early Life Exposome (HELIX) study was to measure and describe multiple environmental exposures during early life (pregnancy and childhood) in a prospective cohort and associate these exposures with molecular omics signatures and child health outcomes. Here, we describe recruitment, measurements available and baseline data of the HELIX study populations.ParticipantsThe HELIX study represents a collaborative project across six established and ongoing longitudinal population-based birth cohort studies in six European countries (France, Greece, Lithuania, Norway, Spain and the UK). HELIX used a multilevel study design with the entire study population totalling 31 472 mother-child pairs, recruited during pregnancy, in the six existing cohorts (first level); a subcohort of 1301 mother-child pairs where biomarkers, omics signatures and child health outcomes were measured at age 6–11 years (second level) and repeat-sampling panel studies with around 150 children and 150 pregnant women aimed at collecting personal exposure data (third level).Findings to dateCohort data include urban environment, hazardous substances and lifestyle-related exposures for women during pregnancy and their offspring from birth until 6–11 years. Common, standardised protocols were used to collect biological samples, measure exposure biomarkers and omics signatures and assess child health across the six cohorts. Baseline data of the cohort show substantial variation in health outcomes and determinants between the six countries, for example, in family affluence levels, tobacco smoking, physical activity, dietary habits and prevalence of childhood obesity, asthma, allergies and attention deficit hyperactivity disorder.Future plansHELIX study results will inform on the early life exposome and its association with molecular omics signatures and child health outcomes. Cohort data are accessible for future research involving researchers external to the project.

Association between DNA methylation and ADHD symptoms from birth to school age: A prospective meta-analysis

“…HELIX consists of six subcohorts, which were pre-processed and analyzed jointly. 45 All cohorts had participants of European ancestry, except HELIX, which also included participants with a Pakistani background living in the UK, which were treated as a separate cohort in the meta-analysis.…”

A Scoping Review on the Characteristics of Human Exposome Studies

“…Approximately a third of the retained exposome studies had a prospective longitudinal design (n = 30, 37%), of which 26 were based on nine large population-based cohorts; the rest four longitudinal studies were relatively small in size, including between 6 and 378 subjects [46][47][48][49]. Out of the 26 studies, eleven were published as part of the Human Early-Life Exposome (HELIX) project using data from six European birth cohorts ( [50][51][52][53][54][55][56]), and among these studies, four belonged to the Spanish INMA (INfancia y Medio Ambiente) [57][58][59][60][61]. Four studies (of the 26) were published as part of the Avon Longitudinal Study of Parents and Children (ALSPAC), a 20-year population-based cohort designed to determine the influence of environmental (physical and psychological) and genetic factors on the health status and development of the offspring.…”

“…Four studies (5%) described the characteristics of exposome cohorts [53,127,72,55] and another (1%) characterized urban environmental and health indicators using the urban exposome framework [73]. Four studies (5%) explored the partitioning of a contaminant between environmental and human biospecimen, of which three considered a biomarker of exposure to environmental contaminants as a study outcome [117,115,80,116] , while only one study (1%) linked occupational records to health outcomes [109].…”

The Early-Life Exposome: Description and Patterns in Six European Countries

“…Follow-up visits of the children in the subcohort took place in 2014 and 2015 in the 6 study centers, and questionnaire information and biological samples for biomarker determination were collected. More details about the subcohort, including recruitment and data collection methods, are available in Maitre et al (2018). Approval was obtained from the national ethics committees for every cohort.…”