Environmental Exposures in Lebanese Infants (EELI) Study: Methods, Findings, and Contextual Considerations to Launch A Birth Cohort in the Eastern Mediterranean Region

BACKGROUND AND AIM: The EELI Study is a longitudinal birth cohort launched in 2021 in Beirut, Lebanon to examine the long-term impact of environmental exposures on the health and wellbeing of prospective Lebanese mothers and infants and disease outcomes. The aim of the present study is to delineate the adopted study design and protocols, current progress, and contextual considerations for the planning and launching of a birth cohort in a resource-limited setting. METHODS: Pregnant women expected to give birth at the Hôtel-Dieu de France University Hospital were recruited. During prenatal clinical visits and through phone interviews, they provided biological specimens and completed multiple questionnaires and semi-structured qualitative interviews. At birth, clinical records and samples of cord blood, colostrum, and meconium were collected. Nested cohort studies focused on the influence of maternal diet on infant gut microbiome and the influence of COVID-19 pandemic, economic crisis, and indoor environmental exposures on maternal mental health are conducted on sub-populations of the study. RESULTS: A sample of n=123 participants has been recruited since the study launch. Over 500 variables have been recorded for each participant, and over 1000 biological specimens have been processed and stored in a biobank for further analysis. Household visits at 1 year from birth are set to be conducted starting May 2022 to complete more questionnaires and collect biological specimens from the infants. The retention rate in Year 1 is 92.2%. CONCLUSIONS: The EELI study establishes a methodological and logistic basis to explore the concept of the exposome and its implementation in resource-limited settings and to establish a toolkit of the SOPs and questionnaires that can be employed by the other countries in the Eastern Mediterranean region. KEYWORDS: birth outcomes, children’s environmental health, exposure assessment, pregnancy outcomes; environmental exposures