title: Patterns of 12-year change in physical activity levels in community-dwelling older women: can modest levels of physical activity help older women live longer?
abstract: Few studies have addressed changes in physical activity participation over time among the elderly. The authors hypothesized that there were distinct trajectories of physical activity level over time and identifiable predictors of such trajectories, as well as that the maintenance of regular physical activity, even below recommended levels, was associated with lower mortality risk. Using longitudinal data (1994-2009) from 433 initially high-functioning older women aged 70-79 years at baseline, a joint latent class and survival mixture model identified 4 activity trajectory classes: always active (16.6%), fast declining (19.2%), stable moderate (32.3%), and always sedentary (31.9%). Obesity, coronary artery disease, chronic obstructive pulmonary disease, depressive symptoms, low self-efficacy, mobility disability, and low energy were associated with sedentary behavior and/or a fast decline in activity. Women in the fast declining and always sedentary classes had hazard ratios for death of 2.34 (95% confidence interval: 1.20, 4.59) and 3.34 (95% confidence interval: 1.72, 6.47), respectively, compared with the always active class; no mortality difference was found between the stable moderate and always active groups (hazard ratio = 1.24, 95% confidence interval: 0.63, 2.47). Our findings suggest that physical activity does not have to be vigorous to be beneficial and that the gain may be the greatest among women who reported the lowest levels of activity.
authors.affiliation: Department of Medicine, Division of Geriatric Medicine and Gerontology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA. qxue@jhsph.edu
authors.forename: Qian-Li
authors.initials: QL
authors.lastname: Xue
authors.forename: Karen
authors.initials: K
authors.lastname: Bandeen-Roche
authors.forename: Thelma J
authors.initials: TJ
authors.lastname: Mielenz
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Seplaki
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Szanton
authors.forename: Roland J
authors.initials: RJ
authors.lastname: Thorpe
authors.forename: Rita R
authors.initials: RR
authors.lastname: Kalyani
authors.forename: Paulo H M
authors.initials: PH
authors.lastname: Chaves
authors.forename: Thuy-Tien L
authors.initials: TT
authors.lastname: Dam
authors.forename: Katherine
authors.initials: K
authors.lastname: Ornstein
authors.forename: Arindam
authors.initials: A
authors.lastname: RoyChoudhury
authors.forename: Ravi
authors.initials: R
authors.lastname: Varadhan
authors.forename: Wenliang
authors.initials: W
authors.lastname: Yao
authors.forename: Linda P
authors.initials: LP
authors.lastname: Fried
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002908:Chronic Disease / Q000401:mortality; D015444:Exercise; D005260:Female; D006306:Health Surveys; D006801:Humans; D057187:Independent Living; D008017:Life Expectancy; D016015:Logistic Models; D008137:Longitudinal Studies; D008390:Markov Chains; D051346:Mobility Limitation; D016016:Proportional Hazards Models; D011446:Prospective Studies; D057185:Sedentary Behavior; D020377:Self Efficacy; D057566:Self Report; D016387:Women's Health