{"doi":"10.1093/geronb/gbaf260","title":"NIA perspective on harmonizing International Health and Retirement Studies (HRS) and Harmonized Cognitive Assessment Protocol (HCAP) studies","abstract":"The National Institute on Aging (NIA) seeks to understand the nature of the aging process to extend the healthy years of life. Toward that end, we support genetic, biological, clinical, behavioral, social, and economic research. The NIA has always had a particular interest in learning how different institutional, policy, social, cultural, and environmental contexts influence aging and life course outcomes. In recent years, as the societal cost and burden of Alzheimer’s disease and Alzheimer’s disease and related dementias (AD/ADRD) has increased, NIA has expanded investments in understanding the causes and consequences of AD/ADRD and dementia. Although there has been a greater focus on later-life cognition specifically, NIA research has continued to fund work on every aspect of aging, especially factors relevant to chronic diseases of midlife and aging and the development of multimorbidity across the lifespan. Work in these areas will help inform policy and interventions to improve the health of older adults in the United States and globally. One approach to doing this is to conduct cross-national analyses. Conducting these types of analyses can only be done if there is longitudinal, nationally representative, harmonized cognition data across countries that allows for these comparisons (Smith, 2021). The NIA supports the Health and Retirement Study (HRS), a comprehensive nationally representative longitudinal study of adults over the age of 50 in the United States with rich omics data, including AD/ADRD blood-based biomarkers, that serves as the leading source of data to understand the life course and aging. The NIA also supports studies based on the principles of the HRS in 47 other countries around the world, which are harmonized to enable cross-national comparisons of the data. A sub-study of the HRS, the Harmonized Cognitive Assessment Protocol (HCAP), has developed a cognitive battery that affords the more precise assessment of cognitive impairment and dementia in HRS as well as providing a blueprint for establishing parallel cognitive batteries that will allow us to do more direct comparisons of HRS data with studies that share at least some of the same cognitive measures, both within the United States, and internationally. In the international context, HCAP is an approach to measuring cognition that can accommodate the need for local adaptation of content to increase its appropriateness across diverse cultural and linguistic contexts. To achieve this goal, we focus on our ability to harmonize cognitive data at the domain and item levels across settings. To date, data have been released for HCAP studies in 14 countries, and studies are underway in 6 additional countries. These completed and ongoing HCAP studies represent approximately 75% of the global population over 65 years of age, which enhances their value as a major data resource for understanding cognitive aging globally (Kobayashi et al., 2024). Coordination among these studies and support for cross-national analyses is facilitated through NIA-supported networks such as the Health and Retirement Studies Around the World (https://event.roseliassociates.com/hrs-around-the-world) and the HCAP Network (https://hcap.isr.umich.edu), as well as the Gateway to Global Aging (https://g2aging.org), a data and information platform developed to facilitate longitudinal and cross-country analyses on aging, focused on international HRS and HCAP studies. Until recently, the bulk of the International HRS and HCAP studies consisted of Western, high-income countries, and there was a concern that this would limit the utility of measures. The NIA felt it was important to include countries from low- and middle-income countries as this approach has the potential to advance knowledge of new risk factors that may have differing distributions or associations with outcomes across different institutional, policy, social, cultural, and environmental contexts to advance science. However, as th","journal":"The Journals of Gerontology Series B","year":2025,"id":549881,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.8908,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1445279,"name":"Minki Chatterji","orcid":null,"position":1,"is_corresponding":false},{"id":1445278,"name":"Jonathan W King","orcid":null,"position":0,"is_corresponding":true}],"reference_count":11,"raw_metadata":null,"created_at":"2026-07-19T02:54:12.321988Z","pmid":"41732983","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}