Adults aged 65+ are at highest risk for severe COVID-19 outcomes, and prior to the distribution of vaccines in the U.S., were strongly advised to quarantine at home to reduce risk of infection. This study examines how COVID-19 restrictions impacted various dementia risk factors and social determinants of health among older adults. Data came from the Systematic Multi-Domain Alzheimers Risk Reduction Trial, a randomized controlled trial of a multi-domain intervention in higher-risk older adults (aged 70-89). A questionnaire was administered to participants (n = 156; 90.7% response rate) between May 2020 and March 2021. The data show a significant decline in social activity, physical activity, and mood among respondents. Compared to living with others, living alone was associated with worsened physical activity, diet, and subjective memory/thinking, adjusted for sex and age. These results suggest that the COVID-19 pandemic exacerbated several risk factors for dementia in older adults, particularly in those living alone.