1. Acknowledgements and Disclosures
Incidence and Trajectory of Obesity in Veterans and Service Members with TBI: A VA TBI Model Systems Study
Racine Marcus Brown, Ph.D.,1 Risa Nakase-Richardson, Ph.D.,1-3 Xinyu Tang, Ph.D.,4 Laura Dreer, Ph.D.,5 Simon Driver, Ph.D.,6 Doug Johnson-Greene, Ph.D.,7 Aaron M. Martin, Ph.D.,2 Tamara McKenzie-Hartman, Psy. D.,8 Mary Jo Pugh, Ph.D.,9,10 Steven Scott, D.O.,11 Timothy Shea, Psy.D.,12 Tong Sheng, Ph.D.,13 Marc A. Silva, Ph.D.1,2
1Center of Innovation for Disability and Rehabilitation Research, James A. Haley Veterans Hospital, Tampa, FL; 2Department of Mental Health and Behavioral Science, James A. Haley Veterans Hospital, Tampa, FL; 3University of South Florida, Tampa, FL; 4University of Arkansas for Medical Sciences, Little Rock, AR; 5University of Alabama at Birmingham, Birmingham, AL; 6Baylor Institute for Rehabilitation, Dallas, TX; 7University of Miami, Coral Gables, FL; 8Defense and Veterans Brain Injury Center, Tampa, FL 9University of Texas Health Science Center, San Antonio, TX; 10South Texas Veterans Health Care System, San Antonio, TX; 11Physical Medicine and Rehabilitation Service, James A. Haley Veterans Hospital, Tampa FL; 12Ohio State University, Columbus, OH; 12Stanford University School of Medicine, Palo Alto, CA; 13Palo Alto VAMC, Palo Alto, CA
Introduction
Results
Discussion
Purpose: Describe BMI and weight classification 1-year post injury in a Veteran and Service Member cohort enrolled in VA TBI Model Systems.
Little literature on the effect of TBI on weight in chronic phase of TBI
To date, no study has examined long-term weight change in Veterans and Service Members
Traumatic Brain Injury (TBI): Complex injury with various, often co-morbid conditions such as cognitive impairment,1 motor impairment,2 sleep apnea,3-5 and hypopituitarism.6,7 TBI is often a chronic condition needing health management.
Obesity: Modifiable risk factor associated with high morbidity and early mortality, with health problems including metabolic syndrome, diabetes,8,9 hypertension,10 heart disease,11,12 and chronic pain.13,14
Traumatic Brain Injury and Obesity
Three contradictory studies on impact of pre-TBI obesity on outcomes15-17
One case series with 2 patients having hyperphagia and becoming obese18
Civilian TBIMS study (N=20) found a mean weight gain of 25.8 lb. post-TBI2
Study from acute care to 3 years post-TBI found 42% gained weight19
Indications of TBI and weight change as complex co-morbidity in need of chronic disease management, but data are needed to inform optimal care
Results of the current study indicate that there is no simple linear trend of increased obesity in VA TBIMS study participants 1 year post-injury. Obesity in TBI-affected Veterans at 1 year post-injury is a notable, but not pervasive problem that may be part of a complex metabolic response to brain injury with a broad array of possible outcomes.
Univariate Models
Demographics, military service status at the time of injury, and potentially related conditions such as injury severity show minimal effect on BMI at 1 year post-injury
BMI at the time of injury supports other findings that obesity at younger ages is associated with greater odds of these conditions later in life21
Smoking tobacco seems to have a suppressive effect on weight gain at one year post injury22
Multivariate Model
That BMI at time of injury would have some influence on BMI at a later point in time is not surprising21
The positive association with FIM motor and the strong positive association with National Guard or Reserve at time of injury require a more careful interpretation
FIM Motor: it is possible that a higher degree of functional independence in mobility allows for a greater degree of uncontrolled eating in some cases
National Guard or Reserve: there is possible deconditioning from having a more active lifestyle pre-TBI to more limited mobility coupled with higher caloric intake in the chronic phase of TBI
Further research with larger sample is needed to confirm these findings
References are available upon request. Please contact Racine Brown at
Table 1: Summary of study variables
Table 2: BMI data at time of injury and 1-year post-injury
Table 3: Univariate and multivariate models for continuous BMI outcome
Subjects with BMI at
Enrollment
1-Year Post-Injury
Enrollment & N
(N=241)
(N=148)
(N=84)
Demographics
Age at Injury
241
25;31;44
148
24;30;50 84
24;30;51
Male
95% (229)
96% (142)
95% (80)
Race
236
146 82
White
74% (175)
69% (101)
70% (57)
Black or African American
10% ( 24)
10% ( 14)
12% (10)
Other
16% ( 37)
21% ( 31)
18% (15)
Hispanic
237
17% ( 40)
17% ( 25) 83
22% (18)
Marital Status
Married
42% (102)
36% (54)
37% (31)
58% (139)
64% (94)
63% (53)
Annual Earnings
177
114 60
≤ $39,999
49% (86)
57% (65)
57% (34)
$40,000 - $79,999
39% (69)
38% (43)
38% (23)
≥ $80,000
12% (22)
5% ( 6)
5% ( 3)
Years of Education
240
≤ HS Diploma
44% (105)
55% (81)
61% (51)
> HS Diploma
56% (135)
45% (67)
39% (33)
Injury-related and Military Characteristics
Cause of Injury
Vehicular
49% (117)
62% (91)
63% (52)
Fall
15% ( 36)
14% (21)
16% (13)
Violence: Penetrating
4% ( 9)
5% ( 7)
4% ( 3)
Violence: Blast
16% ( 38)
7% (10)
5% ( 4)
12% (17)
GCS
175
3; 8;15
131
3; 8;14 74
Active Duty at Time of Injury
59% (143)
55% (82)
48% (40)
Guard or Reserve at Time of Injury
239
6% ( 15)
147
7% ( 10)
8% ( 7)
Years in Active Duty
3; 5;10
2;4;8
Deployed in Combat Zone
67% (160)
60% (88)
62% (52)
Functional and Mental Health Characteristic
PCL-C Total Severity Score
173
20;35;59
105
19;24;38 56
19;27;44
FIM Cognitive at Discharge
228
26;30;32
142
26;30;33 79
FIM Motor at Discharge
230
77;86;90
77;84;89 81
77;84;90
Alcohol and Tobacco Problems
Smoked Cigarettes Prior to Injury
37% ( 88) 89
44% (39)
47% (39)
Methods
BMI Information N
BMI at Time of Injury 84
24;26;29
BMI Classification at Time of Injury
Underweight to Normal Weight 30
36%
Overweight
37 
44%
Obese 17
20%
BMI at 1-year Follow-up
23.3;26.4;29.7
BMI Classification at 1-year Follow-up 29
34% 35
42% 20
24%
Participants: Inclusion and Exclusion Criteria20
Diagnosis of TBI according to case definition
Admission to a VA Polytrauma Rehabilitation Center for comprehensive TBI inpatient rehabilitation
Provision of Informed Consent by Veteran or Proxy
Height and weight reported for time of injury and recorded for 1 year post-injury
No amputations
Measures
BMI=weight(lb.)/height(in)*703
Functional Independence Measure (FIM)
Cognitive
Motor
Behavioral Risk Factor Surveillance System (BRFSS) health questions on tobacco smoking
Procedures
Interview at enrollment and follow-up incorporating measures
Medical record abstraction
Analysis
Linear regression model predicting the continuous outcome
Ordered logistic regression model predicting the ordinal outcome
Multivariable linear regression model for continuous outcome
Univariate Model
Multivariable Model
Risk Factor
Comparison
Estimate (95% CI)
p-value
Age†
1 year increase
0.06 (-0.001, 0.11)
0.054
Dropped
Years of Education
-0.35 (-0.78, 0.08)
0.117
-0.17 (-0.66, 0.32)
0.496
BMI at Enrollment
1 unit increase
0.51 (0.33, 0.69)
<0.001
0.60 (0.38, 0.82)
GCS
0.21 (-0.01, 0.42)
0.061
0.18 (-0.04, 0.41)
0.124
Deployed in Combat Zone
Yes vs. No
-0.44 (-2.43, 1.56)
0.669
-1.47 (-3.88, 0.94)
0.240
PCL-C Total Severity Score
0.02 (-0.04, 0.09)
0.476
0.01 (-0.06, 0.07)
0.778
FIM Cognitive at Discharge
0.01 (-0.15, 0.17)
0.899
-0.10 (-0.39, 0.19)
0.486
FIM Motor at Discharge
0.05 (-0.003, 0.10)
0.11 (0.02, 0.21)
0.029
Smoked Cigarettes Prior to Injury
-2.69 (-4.54, -0.84)
0.005
-2.01 (-4.68, 0.66)
0.148
Active Duty at Time of Injury
-0.69 (-2.62, 1.24)
0.482
1.46 (-0.65, 3.57)
0.183
Guard or Reserve at Time of Injury
2.73 (-0.72, 6.19)
0.120
3.72 (0.43, 7.00)
0.033
Acknowledgements and Disclosures
Financial Disclosures: None.
This research was sponsored by VHA Central Office VA TBI Model Systems Program of Research; Subcontract from General Dynamics Information Technology (W91YTZ-13-C-0015) from the Defense and Veterans Brain Injury Center; US Army Medical Research and Material Command (USAMRMC); Department of Veterans Affairs grants (1 I50 HX , W81XWH ); and Department of Defense Congressionally Directed Medical Research Programs.
This material is the result of work supported with resources and the use of facilities at the James A. Haley Veterans’ Hospital.
The views, opinions, and/or findings contained in this article are those of the authors and should not be construed as an official position by the Department of Defense, Department of Veterans Affairs, or any other federal agency, policy or decision unless so designated by other official documentation.