Physical activity and brain amyloid beta: A longitudinal analysis of cognitively unimpaired older adults

INTRODUCTION: The current study evaluated the relationship between habitual physical activity (PA) levels and brain amyloid beta (A ss) over 15 years in a cohort of cognitively unimpaired older adults. METHODS: PA and A ss measures were collected over multiple timepoints from 731 cognitively unimpaired older adults participating in the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Aging. Regression modeling examined cross-sectional and longitudinal relationships between PA and brain A ss. Moderation analyses examined apolipoprotein E (APOE) e4 carriage impact on the PA-A ss relationship. RESULTS: PA was not associated with brain A ss at baseline (ss = -0.001, p = 0.72) or over time (ss=-0.26, p= 0.24). APOE e4 status did not moderate the PA-A ss relationship over time (ss = 0.12, p = 0.73). Brain A ss levels did not predict PA trajectory (ss = -54.26, p = 0.59). DISCUSSION: Our study did not identify a relationship between habitual PA and brain A ss levels.