Inflammation impacts the relationship between gait speed and cognitive function in caregivers

Caregivers report significantly higher levels of stress than non-caregivers, which is related to increased burden associated with caregiving responsibilities. Chronic stress and caregiver burden are both associated with poorer health outcomes, slowed gait, and worse cognitive function. The positive relationship between gait speed and cognition, notably executive function and processing speed, is well-documented. However, less is understood about factors that influence this relationship. One important and yet unexplored factor is inflammation, as it holds a negative relationship to both gait speed and cognitive function. Thus, the current study explores the impact of inflammation on the relationship between gait speed and cognition in caregivers reporting subjective burden. The sample included 43 well-educated (i.e., 93% with some college education or more) caregivers aged 23 to 83 years (M_age = 58.35) who provided care for someone with traumatic brain injury or dementia. Participants completed a battery that included cognitive (e.g., Stroop Color and Word Test), functional (6-minute walk test), and biological (Interleukin-6 and C-reactive protein) measures. Utilizing a moderation analysis with age as a covariate, caregivers with below average (-1 SD from mean) and average (mean) levels of inflammation exhibited a positive, significant relationship between gait and cognition. However, gait was not associated with cognitive function in caregivers with above average (+1 SD from mean) levels of inflammation, indicating that elevated inflammation suppressed the positive relationship between gait speed and cognition. In both clinical and research settings, it is important to consider the influence of elevated inflammation when assessing gait speed or cognition.