Defining Vitality: Associations of Three Operational Definitions of Vitality with Disability in Instrumental Activities of Daily Living and Frailty among Elderly Over a 3-Year Follow-Up (MAPT Study).

OBJECTIVES: This study aimed to examine the associations of three operational definitions of vitality with variation in instrumental activities of daily living (IADL) and frailty over a 3-year follow-up among non-demented, community-dwelling elderly.
DESIGN: Observational study. SETTING AND PARTICIPANTS: 1,679 elderly >70y (64.7% female) participants of the Multidomain Alzheimer Preventive Trial (MAPT). MEASUREMENTS: Vitality was defined as a psychological concept using three items from the Geriatric Depression Scale; as a physical construct using the highest quartile for hand grip strength; and as global physiological reservoir using a combination of good physical and cognitive functions. Variables were assessed at baseline, 6, 12, 24 and 36 months of follow-up.
RESULTS: Prevalence of high vitality at baseline was 57.1%, 28.5% and 21.6% for psychological, physical, and physiological reservoir, respectively. People with high vitality presented higher IADL scores compared to people with low vitality for all definitions. Analysis from the mixed-effect model found no differences between vitality groups for IADL performance across all definitions. IADL scores improved among subjects with high vitality over time, independent on the definition; while no significant variation was observed among those with low vitality. Participants with low vitality presented 2.0 to 6.1 higher odds of having more frailty components over time (p<0.0001).
CONCLUSION: High vitality defined as a concept related to psychological, physical, or physiological reservoir constructs were positively associated with better IADL performance and with reduced likelihood of frailty worsening over time.