The National Couples’ Health and Time Stress Biology Study (NCHAT-BIO): Wave 1 Methodology Report and Wave 3 Preview

OBJECTIVE: Sexual minority populations are growing, experience elevated physical and mental health risks, and have unique stressor exposures. However, biopsychosocial research on sexual minority individuals at the population level remains limited. Addressing this gap, we launched the National Couples' Health and Time Stress Biology Study (NCHAT-BIO), the first US-based study focused on stress biology within a large, diverse sample of married/cohabiting sexual minority and heterosexual adults. NCHAT-BIO capitalized on the unique opportunity of NCHAT, a population-representative US sample which intentionally oversampled sexual minority respondents. METHODS: NCHAT-BIO was approved by The Ohio State University and Gallup Institutional Review Boards. A total of 950 participants completed at-home dried blood spot (DBS) collection with return by mail. After exclusions, 787 respondent samples were assayed: 44.5% sexual minority, 56.9% assigned female at birth, 55.3% who identified as women, 25% with non-White racial identity, and mean age=42.69 (SD=10.19). Samples were analyzed for interleukin-6 (IL-6), C-reactive protein (CRP), and Epstein Barr Virus (EBV) antibodies. Final analytic samples were: IL-6 (n=452), CRP (n=663), EBV (n=647, including n=84 EBV negative). These biomarker data can be merged with rich NCHAT survey responses, time diaries with an embedded Experience Sampling Method (ESM) component, and contextual state- and county-level indicators. DISSEMINATION: Wave 1 NCHAT-BIO data have been deposited at ICPSR for public release; the current report should be cited in future empirical manuscripts using these data. Wave 1 NCHAT survey data are also at ICPSR, and the two archives will be linked to facilitate integrated use. FUTURE DIRECTIONS: Whole blood data collection from Wave 3 NCHAT participants will begin in 2026. Planned assays, which will also become publicly available, include IL-6, CRP, and epigenetic aging (per DNA methylation).