The Nutrition in Early Life and Asthma (NELA) birth cohort study: Rationale, design, and methods.

This document is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the accepted version of a Published Work that appeared in final form in Paediatric and Perinatal Epidemiology. To access the final edited and published work see https://doi.org/10.1111/ppe.12826Background: Primary prevention strategies for asthma are lacking. Its inception probably starts in utero and/or during the early postnatal period as the developmental origins of health and disease (DOHaD) paradigm suggests. Objectives: The main objective of Nutrition in Early Life and Asthma (NELA) cohort study is to unravel whether the following factors contribute causally to the developmental origins of asthma: (1) maternal obesity/adiposity and foetal growth; (2) maternal and child nutrition; (3) outdoor air pollution; (4) endocrine disruptors; and (5) maternal psychological stress. Maternal and offspring biological samples are used to assess changes in offspring microbiome, immune system, epigenome and volatilome as potential mechanisms influencing disease susceptibility. Population: Randomly selected pregnant women from three health areas of Murcia, a south-eastern Mediterranean region of Spain, who fulfilled the inclusion criteria were invited to participate at the time of the follow-up visit for routine foetal anatomy scan at 19–22 weeks of gestation, at the Maternal-Fetal Medicine Unit of the “Virgen de la Arrixaca” University Clinical Hospital over a 36-month period, from March 2015 to April 2018. Design: Prospective, population-based, maternal-child, birth cohort study. Methods: Questionnaires on exposures and outcome variables were administered to mothers at 20–24 gestation week; 32–36 gestation week; and delivery. Children were surveyed at birth, 3 and 18 months of age and currently at 5 years. Furthermore, physical examinations were performed; and different measurements and biological samples were obtained at these time points. Preliminary results: Among the 1350 women invited to participate, 738 (54%) were finally enrolled in the study and 720 of their children were eligible at birth. The adherence was high with 612 children (83%) attending the 3 months’ visit and 532 children (72%) attending the 18 months’ visit. Conclusion: The NELA cohort will add original and unique knowledge to the developmental origins of asthma