Intervention targets for reducing mortality between mid-adolescence and mid-adulthood: a protocol for a machine-learning facilitated systematic umbrella review

IntroductionA rise in premature mortality-defined here as death during the most productive years of life, between adolescence and middle adulthood (15-60 years)-is contributing to stalling life expectancy in high-income countries. Causes of mortality vary, but often include substance misuse, suicide, unintentional injury and non-communicable disease. The development of evidence-informed policy frameworks to guide new approaches to prevention require knowledge of early targets for intervention, and interactions between higher level drivers. Here, we aim to: (1) identify systematic reviews with or without meta-analyses focused on intervention targets for premature mortality (in which intervention targets are causes of mortality that can, at least hypothetically, be modified to reduce risk); (2) evaluate the review quality and risk of bias; (3) compare and evaluate each review's, and their relevant primary studies, findings to identify existing evidence gaps.Methods and analysisIn May 2023, we searched electronic databases (MEDLINE, PubMed, Embase, Cochrane Library) for peer-reviewed papers published in the English language in the 12 years from 2012 to 2023 that examined intervention targets for mortality. Screening will narrow these papers to focus on systematic reviews with or without meta-analyses, and their primary papers. Our outcome is death between ages 15 and 60 years; with potential intervention targets measured prior to death. A MeaSurement Tool to Assess systematic Reviews (AMSTAR 2) will be used to assess quality and risk of bias within included systematic reviews. Results will be synthesised narratively due to anticipated heterogeneity between reviews and between primary studies contained within included reviews.Ethics and disseminationThis review will synthesise findings from published systematic reviews and meta-analyses, and their primary reviewed studies, meaning ethics committee approval is not required. Our findings will inform cross-cohort consortium development, be published in a peer-reviewed journal, and be presented at national and international conferences.PROSPERO registration numberCRD42022355861.