Abstract
Objectives
To examine body mass index (BMI) trajectories with change in lean mass and physical function in old age.
Design
Prospective cohort study.
Setting
Health, Aging and Body Composition Study.
Participants
Black and white men (n=482) and women (n=516) aged 73.12.7 and initially free of disability.
Measurements
A group-based trajectory model was used to determine BMI trajectories, the path a person's BMI followed over 9years. Lean mass, gait speed, grip strength, and knee extension strength were assessed at baseline and after 9years, and relative changes were calculated. Multivariable linear regression was used to determine associations between trajectories and relative change in lean mass and physical function.
Results
Four BMI trajectories were identified for men and four for women. Although all demonstrated a decline in BMI, the rate of decline differed according to trajectory for women only. Men in Trajectory 4 (mean BMI at baseline 33.9 +/- 2.3kg/m(2)) declined more than those in Trajectory 1 (mean BMI at baseline 22.9 +/- 1.6kg/m(2)) in gaitspeed (-9.91%, 95% confidence interval (CI)=-15.15% to -4.67%) and leg strength (-8.63%, 95% CI=-15.62% to -1.64%). Women in Trajectory 4 (mean BMI at baseline 34.9 +/- 3.0kg/m(2)) had greater losses than those in Trajectory 1 (mean BMI at baseline 20.5 +/- 1.6kg/m(2)) in lean mass in the arms (-3.19%, 95% CI=-6.16% to -0.23%). No other associations were observed.
Conclusion
Obese men had the highest risk of decline in physical function despite similar weight loss between trajectories, whereas overweight and obese women who lost the most weight had the greatest risk of lean mass loss. The weight at which a person enters old age is informative for predicting loss in lean mass and physical function, illustrating the importance of monitoring weight.
Original language | English |
---|---|
Pages (from-to) | 1615-1621 |
Number of pages | 7 |
Journal | Journal of the American Geriatrics Society |
Volume | 63 |
Issue number | 8 |
Early online date | 20 Aug 2015 |
DOIs | |
Publication status | Published - Aug 2015 |
Bibliographical note
This research was supported by National Institute on Aging (NIA) Contracts N01-AG-6–2101, N01-AG-6–2103, and N01-AG-6–2106; NIA Grant R01-AG028050; and National Institute on Nursing Research Grant R01-NR012459. This research was supported in part by the Intramural Research Program of the National Institutes of Health, NIA.Keywords
- aging
- body mass index
- lean mass
- physical function
- trajectories
- FAT-FREE MASS
- OLDER-ADULTS
- WEIGHT-LOSS
- MUSCLE MASS
- AGE
- OVERWEIGHT
- PATTERNS
- ABC