The role of physical activity and diabetes status as a moderator: functional disability among older Mexican Americans.
OBJECTIVE
we investigate the temporal association between the rate of change in physical function and the rate of change in disability across four comparison groups: Those with and without diabetes who report >30 min of physical activity per day, and those who report <30 min of physical activity per day.


METHODS
six waves of longitudinal data from the Hispanic Established Population for Epidemiologic Studies of the Elderly were utilised. At baseline, there were a total of 3,050 elder participants aged 65 years old or greater. The longitudinal rates of change in disability and physical function were compared by the diabetes status (ever versus none) and the physical activity status (less than or greater than or equal to 30 min per day).


RESULTS
disability and physical function data were analysed using a latent growth curve modelling approach adjusted for relevant demographic/health-related covariates. There were statistically significant longitudinal declines in physical function and disability (P < 0.001) in all groups. Most notable, the physical activity status was an important moderator. Those with >30 min of activity demonstrated better baseline function and less disability as well as better temporal trajectories than those reporting <30 min of physical activity per day. Comparisons between diabetes statuses within the same physical activity groups showed worse disability trajectories among those with diabetes.


CONCLUSIONS
a longitudinal decline in physical function and disability is moderated most notably by physical activity. The diabetes status further moderates decline in function and disability over time. Increased physical activity appears to be protective of disability in general and may lessen the influence of diabetes-related disability in older Mexican Americans, particularly at the end of life.
Family and Community Medicine,  The University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78230,  USA.
Raymond F
RF
Palmer
David V
DV
Espino
Jeannae M
JM
Dergance
Johanna
J
Becho
Kyriakos
K
Markides
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D048909:Diabetes Complications / Q000517:prevention & control; D003920:Diabetes Mellitus / Q000503:physiopathology*; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017058:Mexican Americans; D009043:Motor Activity / Q000502:physiology*; D013997:Time Factors