Childhood obesity and precocious puberty in boys and girls: An umbrella review of meta-analytic evidence from the last decade

This project is an umbrella review (overview of systematic reviews and meta-analyses) examining the associations between childhood obesity, metabolic factors, and pubertal timing in boys and girls. Over recent decades, the global rise in pediatric overweight and obesity has coincided with a secular decline in the age of pubertal onset, raising important clinical and public health concerns regarding precocious puberty and its short- and long-term consequences. While numerous observational studies and meta-analyses have investigated these relationships, findings—particularly in boys and for intergenerational and metabolic pathways—remain heterogeneous and fragmented. The primary aim of this umbrella review is to systematically synthesize and critically appraise meta-analytic evidence published over the last decade (January 2015 to the final search date in 2025) addressing: (1) the relationship between childhood overweight/obesity and pubertal timing or precocious puberty; (2) sex-specific differences in these associations; (3) maternal and prenatal determinants, including maternal pre-pregnancy body mass index and gestational weight gain; and (4) metabolic and neuroendocrine correlates of early pubertal activation. Secondary objectives include evaluating bidirectional relationships between obesity and pubertal timing and assessing the methodological quality and overlap of included reviews. Systematic reviews and meta-analyses will be identified through comprehensive searches of PubMed/MEDLINE, Scopus, and Web of Science. Eligible reviews will be assessed for methodological quality using the AMSTAR-2 tool, and overlap of primary studies across reviews will be examined to inform interpretation. Evidence will be synthesized qualitatively at the review level without re-pooling primary data, in accordance with established umbrella review methodology and PRIOR guidance. The expected outcomes include a high-level, sex-specific evidence map summarizing the strength, consistency, and certainty of associations between obesity and pubertal timing, identification of evidence gaps—particularly in boys and intergenerational pathways—and clinically relevant implications for pediatric obesity prevention, early pubertal assessment, and future research directions.