The joint association of obesity and physical activity on cognitive function in Down syndrome

BackgroundLifetime incidence of Alzheimer's disease (AD) in Down syndrome (DS) exceeds 90%. In adults with and without DS, low moderate-to-vigorous physical activity (MVPA) and obesity have independently been associated with AD. Research across other disease conditions indicates MVPA may attenuate some negative consequences of obesity.ObjectiveTo evaluate the potential joint association of obesity and MVPA on cognitive function in adults with DS.MethodsSeventy-five adults with DS (age 39.1 years, 46.7% female) enrolled in the Alzheimer Biomarker Consortium-Down Syndrome (ABC-DS) study and completed a 7-day accelerometer protocol. Cognitive function was assessed using the ABC-DS cognitive battery. Participants were categorized with Obesity (body mass index (BMI) ≥ 30 kg/m²) or No Obesity (BMI < 30 kg/m²). A median split of MVPA was then used to create four groups: No Obesity/High PA (n = 18), No Obesity/Low PA (n = 16), Obesity/High PA (n = 20), and Obesity/Low PA (n = 21). Linear models were used to compare cognitive function across groups.ResultsThe Obesity/High PA group performed better than the No Obesity/Low PA group for episodic memory (β = 4.86, p = 0.009), executive functioning (β = 3.07, p = 0.013), and dementia symptoms (β = -6.57, p = 0.022). The Obesity/High PA group also performed better than the Obesity/Low PA group for memory and orientation (β = 4.43, p = 0.012), social functioning (β = 4.52, p = 0.006), visuo-spatial processing (β = -2.39, p = 0.038), and overall dementia symptoms (β = -7.21, p = 0.016). There were no assessments for which either high PA group performed worse than either Low PA group.ConclusionsPhysical activity may benefit AD-related cognitive function in persons with DS, regardless of obesity status.