Physical health trajectories of young people with neurodevelopmental conditions: a protocol for a systematic review of longitudinal studies.

INTRODUCTION: There is now emerging evidence to suggest a longitudinal association between specific neurodevelopmental conditions (NDCs) in childhood or adolescence (ie, autism, attention deficit hyperactivity disorder (ADHD) and tic disorders) and certain physical long-term conditions (LTCs) in adulthood. However, to date, this literature has never been comprehensively collated and 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.

METHODS AND ANALYSIS: A search strategy has been developed in collaboration with two medical librarians and will be used to conduct systematic searches of MEDLINE, EMBASE, APA PsycINFO, CINAHL and Web of Science. Prospective longitudinal studies exploring the association between three common NDCs in childhood or adolescence (ie, ADHD, autism and tic disorders <18 years of age) and any physical LTC in adulthood (ie, >18 years of age) will be selected through title and abstract review, followed by a full-text review. Data extracted will include the 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 synthesised narratively and, if the data allow, a meta-analysis will also be conducted.

ETHICS AND DISSEMINATION: Ethics 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 publications, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and conference presentations.

PROSPERO REGISTRATION NUMBER: CRD42024516684.