The Epilepsy‐Cog study: Methods to establish a harmonized study of late onset epilepsy in a metacohort of six population‐based cohorts in the United States

OBJECTIVE: With the expected demographic shift toward those ≥65 years of age in the United States, late onset epilepsy (LOE) poses a significant public health issue, yet it has been historically understudied. We are undertaking an effort in the Epilepsy-Cog study to pool individual participant data from six United States-based prospective cohort studies. In this paper, we outline the process for ascertaining epilepsy, harmonizing, and pooling individual participant data across the six cohorts. METHODS: The Epilepsy-Cog study includes individual participant data from six United States-based longitudinal cohort studies: Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Multi-Ethnic Study of Atherosclerosis, Northern Manhattan Study (NOMAS), Reasons for Geographic and Racial Differences in Stroke, and Washington Heights/Inwood Columbia Aging Project. In all cohorts except NOMAS, prevalent and incident epilepsy were ascertained using Medicare claims-based algorithms. In NOMAS, epilepsy cases were identified through cohort-based reporting and medical record review. To perform cross-cohort harmonization of variables, we used the lowest common denominator approach, assigning response categories or value levels in common across all cohorts. RESULTS: From a total of 68 544 participants across six cohorts, 43 753 participants met eligibility criteria for Epilepsy-Cog. Among them, we identified 551 (1.3%) participants with prevalent epilepsy and 1500 (3.4%) participants with incident epilepsy. We have harmonized demographic characteristics, health behaviors, vascular risk factors (VRFs), one genetic variable, medication use, subjective health status measures, incident events, and cause-of-death variables. SIGNIFICANCE: The Epilepsy-Cog pooled cohort of 43 753 participants with and without epilepsy, combined with harmonized demographic, VRF, and event data, offers a unique resource to yield new insights into LOE.

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Publication Details

Journal
Epilepsia
Published
2026-07-02
DOI
https://doi.org/10.1002/epi.70361
Primary Topic
Epilepsy research and treatment
Type
article
Field-Weighted Citation Impact
0.00

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article

The Epilepsy‐Cog study: Methods to establish a harmonized study of late onset epilepsy in a metacohort of six population‐based cohorts in the United States

Natalie Ann Bello, Evan L. Thacker, Emily L. Johnson, Adam M. Brickman et al.
Epilepsia
Epilepsy research and treatment
article

The Epilepsy‐Cog study: Methods to establish a harmonized study of late onset epilepsy in a metacohort of six population‐based cohorts in the United States

Natalie Ann Bello, Evan L. Thacker, Emily L. Johnson, Adam M. Brickman, Sylwia Misiewicz, James Burke, Mitchell S.V. Elkind, Cheng‐Shiun Leu, Tatjana Rundek, Emily M. Briceño, Rebecca F. Gottesman, Hyunmi Choi, Lisandro D. Colantonio, Mary L. Biggs, Danurys Sanchez, Minghua Liu, José Gutierrez, Richard P Mayeux, W. Craig Johnson, Carolyn W. Zhu, Oluwadamilola Obalana, Deborah A. Levine, Christopher Gonzalez, Steven Shea, Josiah Han, Brian C Petersen, Stefany Diaz Andino, W. T. Longstreth, Sofia Pelagalli Maia, Dolly Reyes-Dumeyer, Kevin Strobino, Annette L. Fitzpatrick, Lei Huang, Alden L. Gross, Ligong Chen, Tian Wang
article en

Abstract

OBJECTIVE: With the expected demographic shift toward those ≥65 years of age in the United States, late onset epilepsy (LOE) poses a significant public health issue, yet it has been historically understudied. We are undertaking an effort in the Epilepsy-Cog study to pool individual participant data from six United States-based prospective cohort studies. In this paper, we outline the process for ascertaining epilepsy, harmonizing, and pooling individual participant data across the six cohorts. METHODS: The Epilepsy-Cog study includes individual participant data from six United States-based longitudinal cohort studies: Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Multi-Ethnic Study of Atherosclerosis, Northern Manhattan Study (NOMAS), Reasons for Geographic and Racial Differences in Stroke, and Washington Heights/Inwood Columbia Aging Project. In all cohorts except NOMAS, prevalent and incident epilepsy were ascertained using Medicare claims-based algorithms. In NOMAS, epilepsy cases were identified through cohort-based reporting and medical record review. To perform cross-cohort harmonization of variables, we used the lowest common denominator approach, assigning response categories or value levels in common across all cohorts. RESULTS: From a total of 68 544 participants across six cohorts, 43 753 participants met eligibility criteria for Epilepsy-Cog. Among them, we identified 551 (1.3%) participants with prevalent epilepsy and 1500 (3.4%) participants with incident epilepsy. We have harmonized demographic characteristics, health behaviors, vascular risk factors (VRFs), one genetic variable, medication use, subjective health status measures, incident events, and cause-of-death variables. SIGNIFICANCE: The Epilepsy-Cog pooled cohort of 43 753 participants with and without epilepsy, combined with harmonized demographic, VRF, and event data, offers a unique resource to yield new insights into LOE.

Epilepsia
Brigham Young University (US), American Heart Association (US), Cedars-Sinai Medical Center (US), Johns Hopkins University (US), University of Miami (US), Rosalind Franklin University of Medicine and Science (US), University of Washington (US), Cornell University (US), University of Michigan (US), University of Alabama at Birmingham (US), National Institute of Neurological Disorders and Stroke (US), The Ohio State University (US), Columbia University (US), Icahn School of Medicine at Mount Sinai (US)
National Institute on Aging
Good health and well-being
Openalex Percentile: Top 7%
Epilepsy research and treatment
DOISourceOpenAlex
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