An Examination of the Longitudinal Relationship Between Cognitive Function and Physical Activity Among Older Breast Cancer Survivors in the Thinking and Living With Cancer Study.

Abstract

Older cancer survivors are at risk for cognitive decline. Physical activity can improve cognition, and better cognitive function may facilitate greater physical activity. We examined the potential bidirectional relationship between cognitive function and physical activity in older breast cancer survivors and controls. The sample included women with newly diagnosed, nonmetastatic breast cancer (n = 395) and women without cancer (n = 374) ages 60-98. Participants were recruited as part of a larger multisite study, assessed prior to systemic therapy, and followed yearly for 36 months. Attention, processing speed, and executive function was measured using six neuropsychological tests, self-reported cognitive function using the Perceived Cognitive Impairments subscale of the Functional Assessment of Cancer Therapy-Cognitive Function , and physical activity using the International Physical Activity Questionnaire-Short Form. Separate random intercepts cross-lagged panel models were used to examine the between- and within-person effects for survivors and controls, controlling for age, education, and study site. Survivors reported significantly less physical activity than controls at baseline (1,284.92 vs. 2,085.98 MET min/week, p < .05). When survivors reported higher activity, they simultaneously had better objective cognition at 12 months (β = 0.24, p = .04) and reported better perceived cognition at 12 and 24 months (β = 0.25, p = .03), but this relationship was not seen in controls. Cognition did not predict subsequent physical activity or vice versa in either group. Cognition and physical activity are cross-sectionally associated in survivors, but the expected prospective relationships were not found.