title: Light Intensity physical activity and sedentary behavior in relation to body mass index and grip strength in older adults: cross-sectional findings from the Lifestyle Interventions and Independence for Elders (LIFE) study.
abstract: BACKGROUND
  Identifying modifiable determinants of fat mass and muscle strength in older adults is important given their impact on physical functioning and health. Light intensity physical activity and sedentary behavior are potential determinants, but their relations to these outcomes are poorly understood. We evaluated associations of light intensity physical activity and sedentary time-assessed both objectively and by self-report-with body mass index (BMI) and grip strength in a large sample of older adults.
  
  
  METHODS
  We used cross-sectional baseline data from 1130 participants of the Lifestyle Interventions and Independence for Elders (LIFE) study, a community-dwelling sample of relatively sedentary older adults (70-89 years) at heightened risk of mobility disability. Time spent sedentary and in light intensity activity were assessed using an accelerometer worn for 3-7 days (Actigraph GT3X) and by self-report. Associations between these exposures and measured BMI and grip strength were evaluated using linear regression.
  
  
  RESULTS
  Greater time spent in light intensity activity and lower sedentary times were both associated with lower BMI. This was evident using objective measures of lower-light intensity, and both objective and self-reported measures of higher-light intensity activity. Time spent watching television was positively associated with BMI, while reading and computer use were not. Greater time spent in higher but not lower intensities of light activity (assessed objectively) was associated with greater grip strength in men but not women, while neither objectively assessed nor self-reported sedentary time was associated with grip strength.
  
  
  CONCLUSIONS
  In this cross-sectional study, greater time spent in light intensity activity and lower sedentary times were associated with lower BMI. These results are consistent with the hypothesis that replacing sedentary activities with light intensity activities could lead to lower BMI levels and obesity prevalence among the population of older adults. However, longitudinal and experimental studies are needed to strengthen causal inferences.
authors: MRC Unit for Lifelong Health and Ageing at UCL, London, United Kingdom.
authors: David
authors: D
authors: Bann
authors: Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.
authors: Don
authors: D
authors: Hire
authors: Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida, United States of America.
authors: Todd
authors: T
authors: Manini
authors: MRC Unit for Lifelong Health and Ageing at UCL, London, United Kingdom.
authors: Rachel
authors: R
authors: Cooper
authors: Department of Health Policy Studies and Institute of Gerontology, University of Michigan-Dearborn/Ann Arbor, Ann Arbor, Michigan, United States of America.
authors: Anda
authors: A
authors: Botoseneanu
authors: Northwestern University, Feinberg School of Medicine, Chicago, United States of America.
authors: Mary M
authors: MM
authors: McDermott
authors: Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida, United States of America.
authors: Marco
authors: M
authors: Pahor
authors: Department of Epidemiology, University of Pittsburgh, Pittsburgh, United States of America.
authors: Nancy W
authors: NW
authors: Glynn
authors: Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, United States of America.
authors: Roger
authors: R
authors: Fielding
authors: Stanford University School of Medicine, Stanford, CA, United States of America.
authors: Abby C
authors: AC
authors: King
authors: Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors: Timothy
authors: T
authors: Church
authors: Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.
authors: Walter T
authors: WT
authors: Ambrosius
authors: Thomas M
authors: TM
authors: Gill
authors: Yale School of Medicine, New Haven, Connecticut, United States of America.
authors: Thomas
authors: T
authors: Gill
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D009043:Motor Activity; D057185:Sedentary Behavior; D057566:Self Report
references: Med Sci Sports Exerc. 2001 Jul;33(7):1126-41
references: 11445760
references: Am J Prev Med. 2002 Feb;22(2):120-33
references: 11818183
references: Am J Epidemiol. 2008 Apr 1;167(7):875-81
references: 18303006
references: Sleep. 2008 May;31(5):733-40
references: 18517043
references: Curr Opin Clin Nutr Metab Care. 2008 Nov;11(6):693-700
references: 18827572
references: Annu Rev Public Health. 2009;30:211-25
references: 18976142
references: Am J Clin Nutr. 2009 Feb;89(2):500-8
references: 19116329
references: J Gerontol A Biol Sci Med Sci. 2009 Jan;64(1):90-5
references: 19164269
references: J Aging Phys Act. 2009 Jan;17(1):17-30
references: 19299836
references: Am J Clin Nutr. 2009 Nov;90(5):1336-42
references: 19740971
references: J Gerontol A Biol Sci Med Sci. 2010 Jan;65(1):71-7
references: 19887536
references: J Aging Health. 2010 Mar;22(2):183-96
references: 20051605
references: Diabetologia. 2010 Apr;53(4):624-31
references: 20052455
references: Obes Rev. 2010 Aug;11(8):568-79
references: 20059707
references: Eur J Appl Physiol. 2010 Jul;109(5):953-61
references: 20336310
references: Ageing Res Rev. 2010 Jul;9(3):226-37
references: 20385254
references: BMJ. 2010 Jun 23;340:c2289
references: 20573762
references: Med Sci Sports Exerc. 2011 Feb;43(2):357-64
references: 20581716
references: BMJ. 2010 Sep 09;341:c4467
references: 20829298
references: Am J Epidemiol. 2010 Nov 15;172(10):1155-65
references: 20843864
references: Scand J Med Sci Sports. 2011 Dec;21(6):e168-75
references: 20874860
references: Am J Clin Nutr. 2011 Apr;93(4):826-35
references: 21346093
references: Maturitas. 2011 Jul;69(3):208-19
references: 21596497
references: Med Sci Sports Exerc. 2011 Aug;43(8):1575-81
references: 21681120
references: Am J Prev Med. 2011 Aug;41(2):207-15
references: 21767729
references: J Gerontol A Biol Sci Med Sci. 2011 Nov;66(11):1226-37
references: 21825283
references: Am J Prev Med. 2011 Oct;41(4):376-84
references: 21961464
references: Med Sci Sports Exerc. 2012 Jan;44(1 Suppl 1):S77-85
references: 22157778
references: J Am Geriatr Soc. 2012 Jan;60(1):77-85
references: 22211568
references: J Phys Act Health. 2012 Feb;9(2):225-36
references: 22368222
references: J Gerontol A Biol Sci Med Sci. 2012 Aug;67(8):905-10
references: 22396477
references: Appl Physiol Nutr Metab. 2012 Jun;37(3):540-2
references: 22540258
references: Soc Sci Med. 2012 Aug;75(3):482-90
references: 22580078
references: Int J Epidemiol. 2012 Oct;41(5):1338-53
references: 22634869
references: J Gerontol A Biol Sci Med Sci. 2013 Jun;68(6):631-8
references: 23213030
references: Epidemiol Rev. 2013;35:51-65
references: 23221972
references: Int J Behav Nutr Phys Act. 2012 Dec 18;9:148
references: 23245612
references: JAMA. 2013 Jan 2;309(1):71-82
references: 23280227
references: Am J Prev Med. 2013 Feb;44(2):132-8
references: 23332328
references: PLoS One. 2013;8(2):e56483
references: 23437142
references: Obesity (Silver Spring). 2013 Mar;21(3):E219-28
references: 23592678
references: PLoS One. 2013 May 03;8(5):e63171
references: 23658805
references: J Gerontol A Biol Sci Med Sci. 2013 Dec;68(12):1549-58
references: 23716501
references: PLoS One. 2013 Jun 03;8(6):e66222
references: 23755302
references: Age Ageing. 2013 Nov;42(6):794-8
references: 23981980
references: J Am Med Dir Assoc. 2014 Feb;15(2):150.e11-6
references: 24291347
references: Exerc Sport Sci Rev. 2014 Apr;42(2):53-61
references: 24508740
references: PLoS One. 2014 Feb 06;9(2):e87085
references: 24516543
references: Int J Nurs Pract. 2014 Apr;20(2):212-220
references: 24713018
references: Am J Epidemiol. 2014 May 15;179(10):1197-207
references: 24722997
references: Physiol Behav. 1982 Mar;28(3):545-63
references: 7043508