[Population-based cohorts on health and well-being in childhood and adolescence: a descriptive systematic review and...

Population-based cohorts make it possible to study health and well-being trajectories during childhood and adolescence, their determinants, and their usefulness for informing public policies. The aim of this paper was to identify, compare, and synthesise population-based cohorts on child and adolescent health and well-being at national and international level.

We conducted a descriptive systematic review and comparative analysis of cohorts with a reference publication published in or after 2010, in Spanish or English, including more than 2,000 participants and using either prospective or retrospective longitudinal designs. Hospital-based, local, or disease-specific cohorts were excluded. Cohorts were identified through specialised sources (Birthcohorts.net, CLOSER, CLS-UCL, and the EU Child Cohort Network), bibliographic databases (PubMed, Scopus, Web of Science, and Google Scholar), and snowball searching. Information was extracted on institutional context, governance, design, contents, data access, scientific output, and policy impact. No formal methodological quality or risk-of-bias assessment was performed, as the cohort as a research infrastructure was the unit of analysis.

Nineteen cohorts from twenty-seven countries were selected. European cohorts predominated (twelve out of nineteen), although initiatives were also identified in North America, Asia, Oceania, and one multinational cohort including countries from Africa, Asia, and Central America. Considerable heterogeneity was observed in sample size, recruitment strategies, follow-up intensity, and data accessibility. All cohorts included clinical and/or administrative records, eleven included biological samples, ten genetic information, and sixteen clinical examinations. Funding was predominantly public. Several cohorts showed high scientific output, whereas documented translation into policies, programmes, or planning was more uneven and clearly documented in only a limited number of cohorts. The comparison also allowed the synthesis of selected cohort characteristics relevant to surveillance and policy evaluation.

The identified cohorts constitute strategic and complementary infrastructures for studying child and adolescent health and well-being. Their methodological and governance diversity provides relevant lessons for the design of future cohorts, particularly regarding the balance between population coverage, richness of measurement, record linkage, and transferability to public action.