Neurology
Associations of the COVID-19 pandemic and pandemic-related exposures with cognitive function in women: A prospective cohort study Siwen Wang* Siwen Wang Anthony Menor Lori B Chibnik Jae H Kang Chirag Vyas Deborah Blacker Laura D. Kubzansky Karestan C Koenen Andrea L Roberts
Background The COVID-19 pandemic involved factors possibly associated with cognitive decline, such as bereavement and SARS-CoV-2 infection. We examined the associations of the COVID-19 pandemic and pandemic-related exposures with change in cognitive function among middle-aged women.
Methods We included 20,660 female participants from the Nurses’ Health Study II, aged 51–70 years, who had completed one or more cognitive assessments (Oct 2014–Sep 2022). Cognitive function was measured using the Cogstate Brief Battery, a self-administered online battery. Participants completed assessments every 6–12 months, contributing 53,534 assessments in total. Of these, 9,249 assessments (17%) were performed after the beginning of the pandemic (on Mar 1, 2020, or thereafter). 15,091 women had only pre-pandemic and 378 women had only post-pandemic assessments. We calculated a psychomotor speed and attention composite score, a learning and working memory composite score, and a global score. We fit weighted multivariable-adjusted generalized estimating equation models to examine the differences as well as the rate of cognitive change pre- and post-pandemic.
Results The mean (SD) age at first cognitive assessment was 62.8 (4.9) years, and at the start of the pandemic it was 66.4 (4.6) years. After adjustment for age at assessment, educational attainment of participants and their parents, cognitive test practice effects, and comorbidities (e.g., diabetes, hypertension), we did not observe a difference in cognitive function comparing assessments taken after the pandemic vs. before (β [95% CI], psychomotor speed and attention: -0.01 SD [-0.04, 0.02]; learning and working memory: -0.01 SD [-0.04, 0.02]; global score: -0.01 SD [-0.03, 0.01]). SARS-CoV-2 infection, post-COVID-19 conditions (e.g., long COVID), and death of loved ones were not associated with rate of cognitive change. Rates of pre- and post-pandemic cognitive decline did not differ significantly across strata of comorbidities (e.g., hypertension, diabetes, depression).
Conclusions The COVID-19 pandemic and COVID-19-related events were not associated with cognitive decline in this large cohort of older women with up to 2.5 years of follow-up after pandemic onset. Future studies with more diverse study populations are required to confirm our findings.