title: Association Between Objectively Measured Physical Activity and Cognitive Function in Older Adults-The Reasons for Geographic and Racial Differences in Stroke Study.
abstract: OBJECTIVE
  To examine the relationship between objectively measured physical activity (PA) and cognitive function in white and black older adults.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  REasons for Geographic and Racial Differences in Stroke (REGARDS) study.
  
  
  METHODS
  Older adults who provided valid data from accelerometer and cognitive function tests (N = 7,098).
  
  
  METHODS
  Accelerometers provided estimates of PA variables for 4 to 7 consecutive days. PA cut-points of 50 counts per minute (cpm) and 1,065 cpm were applied to differentiate between being sedentary and light PA and between light and moderate to vigorous PA (MVPA), respectively. Prevalence of cognitive impairment was defined using the Six-Item Screener (<4/6). Letter fluency, animal fluency, word list learning, and Montreal Cognitive Assessment (orientation and recall) were used to assess memory and executive function.
  
  
  RESULTS
  Of 7,098 participants (aged 70.1 ± 8.5, 54.2% female, 31.5% black), 359 (5.1%) had impaired cognition within ±12 months of PA measurement. The average proportion of time spent in MVPA (MVPA%) was 1.4 ± 1.9%. Participants in the highest quartile of MVPA% (~258.3 min/wk) were less likely to be cognitively impaired than those in the lowest quartile (odds ratio = 0.65, 95% confidence interval = 0.43-0.97). MVPA% was also significantly associated with executive function and memory z-scores (P < .001). Similar analyses of proportion of time spent in light PA (LPA%) and sedentary time (ST%) showed no significant associations with cognitive function.
  
  
  CONCLUSIONS
  Higher levels of objectively measured MVPA%, rather than LPA% or ST%, were associated with lower prevalence of cognitive impairment and better performance in memory and executive function in aging people. The amount of MVPA associated with lower prevalence of cognitive impairment is consistent with meeting PA guidelines.
authors.affiliation: Institute of Sports Biology, Shaanxi Normal University, Shaanxi, China.
authors.forename: Wenfei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Howard
authors.affiliation: Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Virginia G
authors.initials: VG
authors.lastname: Wadley
authors.affiliation: Prevention Research Center, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina.
authors.forename: Brent
authors.initials: B
authors.lastname: Hutto
authors.affiliation: Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina.
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
authors.affiliation: Department of Public Health Sciences, College of Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: John E
authors.initials: JE
authors.lastname: Vena
authors.affiliation: Institute for Social Research, University of Michigan, Ann Arbor, Michigan.
authors.forename: Natalie
authors.initials: N
authors.lastname: Colabianchi
authors.affiliation: Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: David
authors.initials: D
authors.lastname: Rhodes
authors.affiliation: Institute of Sports Biology, Shaanxi Normal University, Shaanxi, China.|Exercise and Wellness Program, School of Nutrition and Health Promotion, Arizona State University, Phoenix, Arizona.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Hooker
keywords: accelerometry; aging; cognitive function; physical activity