Influence of Physical Activity Levels and Functional Capacity on Brain β-Amyloid Deposition in Older Women

Physical activity (PA) and Alzheimer's disease are associated. However, how PA influences the cerebral beta-amyloid (A beta) burden remains unclear. The aim of this study was to determine if PA levels and/or functional capacity (FC) are associated with A beta plaque deposition, and whether these associations differed according to APOE-epsilon 4 genotype. A total of 117 women (69.7 +/- 2.6 years; 33.3% APOE-epsilon 4-carriers) from the Women's Healthy Ageing Project cohort (WHAP) were analyzed. PA was measured using the International Physical Activity Questionnaire and, FC was evaluated using the Timed Up and Go test (TUGt). Positron emission tomography with F-18 Florbetaben was carried out to assess cerebral A beta burden, and quantified using standardized uptake value rations. The sample was split into PA and TUGt tertiles (T1, T2 and T3), and compared according to APOE-epsilon 4 genotype (positive/negative). There were no significant differences in A beta accumulation according to PA tertiles and APOE-epsilon 4 genotype. Regarding FC, APOE-epsilon 4+ participants in the first TUGt tertile (high performance) obtained significant lower A beta accumulations compared with the other two tertiles (p < 0.05). Comparing between genotypes, greater A beta depositions were found between T2 and T3 in APOE-epsilon 4+ compared with those who were APOE-epsilon 4- (p < 0.05). Values of TUGt >= 6.5 s (APOE-epsilon 4+) and 8.5 s (APOE-epsilon 4-) were associated with an increased risk of having higher A beta retention. In conclusion, low performance in TUGt is associated with a negative effect on brain pathology with increasing cerebral A beta depositions in older women who are APOE-epsilon 4+. In physically active older women (> 600 METs center dot min/week), higher PA levels are not associated with reduction in A beta depositions.