Everyday Physical Activity and Mobility Affect Executive Function Performance and Change in Older Adults: Evaluating Independent and Moderating Effects of Genetic Risk for Alzheimer’s Disease

• Author / Creator

  Thibeau, Sherilyn D

• Objective: Among older adults, everyday physical activity (EPA) and mobility (MOB) are important contributors to age-related variability and change in executive functioning (EF). However, the role of these health and lifestyle influences may be moderated by genetic factors, especially those known to be risk factors for neurodegenerative disease. The goals of this research were to (a) confirm a single-factor EF latent variable fit this sample of participants and maintained measurement invariance, (b) determine the best fitting latent growth models for EF, EPA, and MOB, (c) examine how EPA, MOB and four genetic factors independently affect EF performance and change, (d) test moderating effects of the four genetic factors on EPA-EF relationships, and (e) test moderating effects of the four genetic factors on MOB-EF relationships. Method: The sample consisted of genotyped older adults (N=577, M age = 70.47 years) over three waves (9 years) of the Victoria Longitudinal Study. The four genetic factors were Apolipoprotein E (APOE rs7412 and rs429358) Clusterin (CLU rs11136000), Complement receptor 1 (CR1 rs6656401), and Phosphatidylinositol binding Clathrin Assembly Protein (PICALM rs541458). Analyses included (a) confirmatory factor analysis establishing a single latent EF factor from four standard EF tasks, (b) latent growth modeling (Mplus 7.0) over a 40-year band of aging (ages 53-95), and (c) path analyses to investigate the independent and interactive effects of APOE, CLU, CR1, PICALM, EPA and MOB on EF. Results: First, the single factor EF latent variable fit the sample of participants and had configural, metric and partial scalar invariance. Second, older adults significantly differed in both MOB and EF performance, exhibited significant 9-year EF and MOB change and individual variability in rate of MOB and EF decline. Third, higher levels of EPA were associated with better EF performance at the centering age (75 years) and less EF decline. In addition, higher levels of MOB were associated with better EF performance. Fourth, within the APOE ε3 (non-risk) and the CLU risk (C+) groups, those with higher EPA exhibited better EF performance and more gradual change over time than those with lower EPA. Also, when APOE and CLU were used to create a risk score, higher levels of EPA were associated with higher levels of EF performance for the low-risk group, and more gradual 9-year change for both the low and mid-risk groups. Fifth, the effect of level of mobility on level of EF was stronger for both the APOE ɛ4 (risk) and CLU risk carriers than their non-risk peers. However, although this pattern of results was similar when APOE and CLU were combined into a risk score, moderation was not evidenced. Conclusion: For individuals with low genetic risk for AD, participating in higher levels of EPA was beneficial to EF performance and change. In addition, level of mobility was strongly related to level of EF performance for individuals with high genetic risk for AD.

• Subjects / Keywords

  • Everyday physical activity
  • CLU
  • Mobility
  • Executive Function
  • Victoria Longitudinal Study
  • APOE
  • Older adults

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3WH2DS23

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.