The Physical Health Trajectories of Young People with Neurodevelopmental Conditions: A Protocol for a Systematic Review of Longitudinal Studies
Authors: Wilson Naomi , Gajwani Ruchika , Fleming Michael , Findlay Mia , Stocks Helen , Walker Graham , Corrigan Naeve , Minnis Helen 
Published: March 2024

AbstractIntroductionIt is now widely acknowledged that without appropriate support, young people with neurodevelopmental conditions (NDCs) are at an increased risk of many of the social and psychiatric outcomes which are known to be key drivers of physical health inequalities. Despite this, until recently relatively little attention has been paid to their physical health trajectories. There is now emerging longitudinal evidence to suggest an association between specific NDCs in childhood or adolescence and certain physical long-term conditions (LTCs) in adulthood. However, to date this literature has never been comprehensively appraised. As a result, our understanding of all the future health risks that young people with NDCs may collectively be at risk of is limited and the factors which drive these adult health outcomes also remain obscure.MethodsA search strategy has been developed in collaboration with two medical librarians and will be used to conduct systematic searches of Medline, Embase, APA PsycINFO, Cumulative Index to Nursing and Allied Health Literature, and Web of Science. Prospective longitudinal studies exploring the association between three common NDCs in childhood or adolescence (i.e., ADHD, Autism, and Tic Disorders <18 years of age) and any physical LTC in adulthood (i.e., > 18 years of age) will be selected through title and abstract review, followed by a full-text review. Data extracted will include definition of exposure and outcome, mediators or moderators investigated, confounders adjusted for, and crude and adjusted effect estimates. Risk of bias assessment will be conducted. Results will be synthesized narratively and if the data allow, a meta-analysis will also be conducted.Ethics and disseminationEthics approval is not applicable for this study since no original data will be collected. The results of the review will be widely disseminated locally, nationally, and internationally through peer-reviewed publication, adhering to the PRISMA statement, and conference presentations.Article SummaryStrengths and Limitations of This StudyTo our knowledge, this is the first systematic review synthesising and critically assessing evidence from longitudinal, observational studies on the association between NDCs in childhood or adolescence and physical long-term conditions (LTCs) in adulthood.We will conduct a comprehensive search across multiple databases, without publication restrictions and will adhere to Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) recommendations to ensure methodological rigor.This study’s focus on prospective longitudinal evidence from observational studies will strengthen the conclusions drawn from results and may facilitate causal inference across studies.Depending on its findings, this study may represent a healthier sample of people with NDCs due to studies with significant loss to follow-up.We plan to meta-analyse outcome data; however due to possible heterogeneity between studies this may not be appropriate.