Early Life Determinants of Childhood Health up to 9–11 Years: The ROLO Longitudinal Birth Cohort Study

Background: The developmental origins of health and disease paradigm suggests that early life factors may determine long-term health outcomes. The first decade of life up to the preteen period (9-11 years of age) represents an important developmental phase to explore these interrelationships, before the biological and behavioural changes that are associated with puberty. Longitudinal birth cohorts provide a unique opportunity to better understand the associations of early life exposures with health outcomes across the life course and understanding the experience of young birth cohort participants is vital. This thesis explores a range of early life factors that may influence health outcomes in the first decade of life. It also describes the views of youth regarding their involvement in a birth cohort. Methods: This thesis is an analysis of data from the ROLO (Randomised cOntrol trial of a LOw glycaemic index diet in pregnancy to prevent macrosomia) longitudinal birth cohort study. Mother-child pairs attended postnatal follow-up visits up to 9-11 years of age. Maternal dietary data was collected during pregnancy. Repeated measures of child general health, anthropometry, nutrition, physical activity, and screen time were obtained at postnatal follow-up visits. Child body composition, blood pressure, heart rate, cardiorespiratory endurance, and blood biomarkers were obtained at 9-11 years of age. Several maternal and child factors were available for inclusion as potential covariates in analyses. The acceptability of research methods used at the ROLO Preteen study was assessed using a Likert-style questionnaire. The views of young people regarding their participation in a birth cohort were explored through public and patient involvement meetings. Results: There was some evidence to suggest that a low glycaemic index dietary intervention in pregnancy was associated with a reduced risk of developing asthma in childhood at 5 years of age, particularly in children born to mothers with lower educational attainment. Macrosomia was associated with early, but not later, childhood growth trajectories. There was no strong evidence to suggest that macrosomia alone was a risk factor for adverse cardiometabolic health at 9-11 years of age. Childhood nutritional factors throughout the first decade of life were associated with certain cardiometabolic outcomes at 9-11 years of age. Diet quality deteriorated and became more pro-inflammatory from 5 to 9-11 years of age. Higher physical activity at 9-11 years of age was associated with lower sum of skinfolds and higher cardiorespiratory endurance at the same time point. There were no participants of the ROLO Preteen follow-up who rated the study measurements, exercises, or questionnaires as unacceptable research methods. Circumferences of the neck and mid-upper arm were strongly associated with several body composition parameters in preteens. Public and patient involvement discussions identified two themes of importance that were related to the fun aspects of participating in research and the use of social media in this age group. Conclusion: This thesis provides novel insights into the role of early life factors during prenatal and postnatal development on health outcomes up to the preteen years, and into the views of Irish youth who are involved in a longitudinal birth cohort study. Our findings strengthen the impact of longitudinal research and highlight the importance of pregnancy and the first decade of a child’s life as windows of opportunity to intervene and potentially improve health outcomes for current and future generations. New insights into the experiences of youth participating in a birth cohort were identified, that may guide future meaningful and enjoyable health research investigations with young people.