Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Arts and Sciences



First Advisor

Dr. Suzanne C. Segerstrom


Segerstrom et al. (2017) found that more repetitive thought (RT) was related to lower interleukin-6 (IL-6), in older adults at average IQ. This study aimed to replicate and extend this finding in midlife adults, with a daily measure of RT, and additional inflammatory biomarkers. 153 participants were drawn from the Midlife in the United States (MIDUS) Refresher project; ages 25-70 (M = 45.07, SD = 10.96), 50.3% female, and 83% Caucasian. Cognition was assessed via the Brief Test of Adult Cognition by Telephone, biological data via fasted blood draw, and RT data were collected as part of the National Study of Daily Experiences daily diary. Total RT (amount one engages in RT) and RT valence (positive vs. negative thought content) were analyzed. As IQ increased, more positive RT was associated with lover levels of IL-6 and CRP after adjusting for age, BMI, and statin use (β = -.161, p = .029; β = -.240, p = .002). Results did not replicate Segerstrom et al. (2017) but suggested that crystallized intelligence and RT total reflect a cognitive system different than that of fluid intelligence, executive functioning, and RT valence. Future studies should continue to investigate effects of RT on health outcomes.

Digital Object Identifier (DOI)

Funding Information

Since 1995 the MIDUS study has been funded by the following: John D. and Catherine T. MacArthur Foundation Research Network, National Institute on Aging (P01-AG020166), National institute on Aging (U19-AG051426). Biomarker data collection was further supported by the NIH National Center for Advancing Translational Sciences (NCATS) Clinical and Translational Science Award (CTSA) program as follows: UL1TR001409 (Georgetown), UL1TR001881 (UCLA), 1UL1RR025011 (UW).