The Importance of Mid-to-Late-Life Body Mass Index Trajectories on Late-Life Gait Speed.
BACKGROUND
Prior studies suggest being overweight may be protective against poor functional outcomes in older adults.


METHODS
Body mass index (BMI, kg/m2) was measured over 25 years across five visits (1987-2011) among Atherosclerosis Risk in Communities Study participants (baseline Visit 1 n = 15,720, aged 45-64 years). Gait speed was measured at Visit 5 ("late-life", aged ≥65 years, n = 6,229). BMI trajectories were examined using clinical cutpoints and continuous mixed models to estimate effects of patterns of BMI change on gait speed, adjusting for demographics and comorbidities.


RESULTS
Mid-life BMI (baseline visit; 55% women; 27% black) was associated with late-life gait speed 25 years later; gait speeds were 94.3, 89.6, and 82.1 cm/s for participants with baseline normal BMI (<25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30) (p < .001). In longitudinal analyses, late-life gait speeds were 96.9, 88.8, and 81.3 cm/s for participants who maintained normal, overweight, and obese weight status, respectively, across 25 years (p < .01). Increasing BMI over 25 years was associated with poorer late-life gait speeds; a 1%/year BMI increase for a participant with a baseline BMI of 22.5 (final BMI 28.5) was associated with a 4.6-cm/s (95% confidence interval: -7.0, -1.8) slower late-life gait speed than a participant who maintained a baseline BMI of 22.5.


CONCLUSIONS
Being overweight in older age was not protective of mobility function. Maintaining a normal BMI in mid- and late-life may help preserve late-life mobility.
Department of Medicine/Geriatrics.
B Gwen
BG
Windham
Department of Data Science, University of Mississippi Medical Center, Jackson.
Michael E
ME
Griswold
Department of Data Science, University of Mississippi Medical Center, Jackson.
Wanmei
W
Wang
Department of Epidemiology, University of North Carolina at Chapel Hill.
Anna
A
Kucharska-Newton
Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis.
Ellen W
EW
Demerath
University of Texas School of Public Health in Austin, Department of Epidemiology, Human Genetics, and Environmental Sciences.
Kelley Pettee
KP
Gabriel
University of Texas School of Public Health, Department of Epidemiology, Human Genetics, and Environmental Sciences.
Lisa A
LA
Pompeii
Department of Medicine/Geriatrics.
Kenneth
K
Butler
Center on Diabetes, Obesity, and Metabolism; Wake Forest School of Medicine, Winston-Salem, North Carolina.
Lynne
L
Wagenknecht
Sticht Center on Aging; Wake Forest School of Medicine, Winston-Salem, North Carolina.
Stephen
S
Kritchevsky
Department of Medicine/Geriatrics.
Thomas H
TH
Mosley
D000368:Aged; D000375:Aging / Q000208:ethnology / Q000502:physiology; D044383:Black People / Q000706:statistics & numerical data; D015992:Body Mass Index; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D012307:Risk Factors; D013223:Statistics as Topic; D014481:United States / Q000453:epidemiology; D016138:Walking / Q000502:physiology; D000072797:Walking Speed; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American
Longitudinal; Mobility; Overweight