title: Longitudinal changes in mobility among nonagenarians: the Vitality 90+ Study.
abstract: BACKGROUND
  Several studies have focused on predictors of mobility limitations and disabilities. Yet little is known about the pace and patterns of mobility changes among very old people. This study examined changes in functional mobility among individuals aged 90 years and older during a 2-9-year follow-up. In addition, we were interested in the patterns of mobility changes.
  
  
  METHODS
  Data were collected through a mailed questionnaire in the years 2001, 2003, 2007 and 2010. The study population (n = 948) consisted of individuals from three cohorts (2001, 2003, 2007) who participated in at least two survey rounds and answered the mobility questions. The length of the follow-up varied from 2-9 years between individuals as well as according to how many times an individual took part in the survey. Multilevel ordinal logistic regression analysis was used to evaluate the effects of time, age, gender, cohort and chronic conditions on changes in mobility.
  
  
  RESULTS
  At the baseline, "younger" old people, men and individuals in the cohorts for 2003 and 2007 had significantly better mobility compared with women, older individuals and individuals in the 2001 cohort. In addition, individuals with fewer chronic conditions had better mobility than those with more diseases. Mobility declined for most of the participants during the follow-up. The difference in the change in mobility over time for gender, age or chronic conditions was not statistically significant. The analyses were performed with a subgroup of participants aged 90-91 years at the baseline, and results did not differ substantially from the results for the entire study sample. However, the effect of chronic conditions on the change in mobility was statistically significant among participants aged 90-91years.
  
  
  CONCLUSIONS
  No differences were observed in the rate of mobility decline over time between age or gender. The effect of chronic conditions on the change in mobility was significant only among individuals aged 90-91 years. The prevention efforts are important and should focus even more, also among the oldest-old, on additional modifiable risk factors such as maintaining muscle strength.
authors.affiliation: School of Health Sciences and Gerontology Research Center, University of Tampere, 33014, Tampere, Finland. kristina.tiainen@uta.fi.
authors.forename: Kristina
authors.initials: K
authors.lastname: Tiainen
authors.affiliation: School of Health Sciences and Gerontology Research Center, University of Tampere, 33014, Tampere, Finland. jani.raitanen@uta.fi.|UKK-Institute for Health Promotion Research, P.O. Box 30, 33501, Tampere, Finland. jani.raitanen@uta.fi.
authors.forename: Jani
authors.initials: J
authors.lastname: Raitanen
authors.affiliation: School of Health Sciences and Gerontology Research Center, University of Tampere, 33014, Tampere, Finland. elina.m.vaara@gmail.com.|Department of Social Research, University of Helsinki, P.O. Box 54, 00014, Helsinki, Finland. elina.m.vaara@gmail.com.
authors.forename: Elina
authors.initials: E
authors.lastname: Vaara
authors.affiliation: School of Health Sciences and Gerontology Research Center, University of Tampere, 33014, Tampere, Finland. antti.hervonen@uta.fi.
authors.forename: Antti
authors.initials: A
authors.lastname: Hervonen
authors.affiliation: School of Health Sciences and Gerontology Research Center, University of Tampere, 33014, Tampere, Finland. marja.jylha@uta.fi.|Institute for Advanced Social Research, University of Tampere, 33014, Tampere, Finland. marja.jylha@uta.fi.
authors.forename: Marja
authors.initials: M
authors.lastname: Jylhä
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000502:physiology* / Q000523:psychology; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D051346:Mobility Limitation; D053580:Muscle Strength / Q000502:physiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors