title: Accelerometry-Assessed Latent Class Patterns of Physical Activity and Sedentary Behavior With Mortality.
abstract: BACKGROUND
  Latent class analysis provides a method for understanding patterns of physical activity and sedentary behavior. This study explored the association of accelerometer-assessed patterns of physical activity/sedentary behavior with all-cause mortality.
  
  
  METHODS
  The sample included 4,510 U.S. National Health and Nutrition Examination Survey participants aged ≥40 years enrolled in 2003-2006 with mortality follow-up through 2011. Participants used a hip-worn accelerometer for 1 week that provided minute-by-minute information on physical activity/sedentary behavior. Accelerometry patterns were derived using latent class analysis. Cox proportional hazards models provided adjusted hazard ratios with 95% CIs. Analyses were conducted from 2014 to 2016.
  
  
  RESULTS
  During an average of 6.6 years of follow-up, 513 deaths occurred. For average counts/minute, the more-active classes had a lower risk of mortality compared with the lowest (Class 1). Findings were generally similar for percentage of the day in minutes and bouts of moderate to vigorous physical activity, defined two ways. For percentage of the day in sedentary behavior, generally no associations were identified. However, the class with the highest percentage of the day in sedentary bouts (Class 1) had a higher risk of mortality (adjusted hazard ratio, 2.10; 95% CI=1.11, 3.97) versus the class with fewer sedentary bouts (Class 7).
  
  
  CONCLUSIONS
  In this national observational study, time spent in physical activity reduced the risk of all-cause mortality and time spent in sedentary bouts increased the risk of all-cause mortality, regardless of how both were accumulated. The latent class analysis contributed to understanding the impact of patterning of physical activity and sedentary behavior on mortality.
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina; Center for Health Promotion and Disease Prevention, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina. Electronic address: kelly_evenson@unc.edu.
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Evenson
authors.affiliation: Department of Biostatistics at the Gillings School of Global Public Health, Carolina Population Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Herring
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Fang
authors.initials: F
authors.lastname: Wen
mesh_terms: D061725:Accelerometry; D000328:Adult; D000368:Aged; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D009749:Nutrition Surveys; D016016:Proportional Hazards Models; D012307:Risk Factors; D057185:Sedentary Behavior