Obesity is associated with physical disability through both direct pathways (e.g., lower extremity pain, insufficient muscle strength) and indirect pathways (obesity-related comorbidities and inflammation). Furthermore, diabetes, a major obesity-related health condition, is associated with increased risk of disability and accelerated declines in physical and cognitive function. The investigators preliminary data suggest that intentional weight loss improves physical function, and there is strong circumstantial evidence that it would also benefit cognitive function. To evaluate the role of intentional weight loss on physical and cognitive function, the investigators propose an ancillary study to the on-going Look AHEAD (Action for Health in Diabetes) trial. Look AHEAD is a multi-center, randomized clinical trial to examine the effects of a 4-year lifestyle intervention designed to achieve and maintain weight loss through decreased caloric intake and exercise in overweight or obese men and women aged 45-74 years with type 2 diabetes. The investigators propose to add validated and well-established measures of physical and cognitive performance to the year 8 follow-up visit - during the trial's weight maintenance phase - in \~1000 participants at 4 of the 16 Look AHEAD field sites (Colorado, Memphis, Pennington and Pittsburgh). The specific aims of this ancillary study are: 1) To determine the long-term effects of a lifestyle intervention designed to achieve and maintain weight loss on physical function; and 2) To determine the long-term effects of a lifestyle intervention designed to achieve and maintain weight loss on cognitive function. In addition, the investigators hypothesize that in the intervention group, larger initial weight loss, better weight loss maintenance, and higher physical activity will be associated with better physical and cognitive function. The investigators also hypothesize that in the control group weight loss will be associated with worse physical and cognitive function than in those who are weight stable or who have gained weight. The number of obese older adults is rising rapidly and there are few data to guide an evidence-based clinical response to their management. The results of this study will provide the first direct evidence of the role of long-term intentional weight loss on the maintenance of physical and cognitive function in older obese adults with diabetes. Since this study is being done as an ancillary study to an on-going trial it can be done in a timely and cost-efficient manner.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
1,089
Intensive Lifestyle Intervention that includes diet, physical activity, and behavior modification. The goal of the ILI intervention was for individuals to achieve and maintain a loss of at least 7% of initial body weight.
It offers an educational program to participants including developing support groups. Providing such benefits helps retain these participants in the trial.
University of Colorado Health Sciences Center
Aurora, Colorado, United States
Pennington Biomedical Research Center
Baton Rouge, Louisiana, United States
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
The University of Tennessee-Memphis
Memphis, Tennessee, United States
Short Physical Performance Battery (SPPB) Score
The Short Physical Performance Battery (SPPB) was administered to assess lower extremity physical performance and consisted of standing balance tasks (side-by-side, semi- and full-tandem stands for 10 seconds each), time to complete 5 repeated chair stands, and a 6-m walk to assess usual gait speed. Each of the three performance measures was assigned a score ranging from 0 (inability to perform the task) to 4 (the highest level of performance) and summed to create an SPPB score ranging from 0 to 12 (best). Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Gait Speed Over 400 m
A 400 m walk was administered to assess endurance. Participants were instructed to walk at their usual pace and time to complete the 400-m walk was recorded. The 400-m walk test was terminated if the participant reported chest pain, tightness or pressure, significant shortness of breath or difficulty breathing, feeling faint, lightheaded or dizzy, or other pain (e.g., leg pain).Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Grip Strength
Grip strength (kg) was measured twice in each hand using an isometric Hydraulic Hand Dynamometer (Jamar, Bolingbrook, IL). The maximum of the force from two trials for the stronger hand was used in the analyses. Participants with severe hand pain or recent surgery in both hands were excluded from testing. Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Knee Extensor Strength
Maximum knee extensor strength (one repetition maximum (1RM)) was assessed on a Nautilus One™ Leg Extension machine. Participants with prior knee surgery on both knees where all or part of the joint was replaced were excluded from testing. The right leg was tested unless there was a contraindication (e.g., prior knee surgery). If participants experienced knee pain during the test and there were no contraindications to test the other leg, the other leg was tested; if participants experienced knee pain on the other leg, the test was terminated. Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Trail Making Test (Part A & B)
Trail Making Tests A and B was used to assess attention and concentration (Part A) and executive function (Part B). Part A measures the time (in seconds) to draw lines to connect circled numbers in a numerical sequence and Part B measures the time (in seconds) to draw lines to connect circled numbers and letters in an alternating numeric and alphabetic sequence as rapidly as possible. The difference (in seconds; greater time indicates worse performance) in performance on Part B minus Part A was used in analysis to represent the contrast between performance on the simple (Part A) and alternating conditions (Part B). Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Digit Symbol Substitution Test (DSST)
The Digit Symbol Substitution Test (DSST) was used to assess working memory. Participants were presented with a legend at the top of the page showing the boxes each with a number from 1 to 9 and below each numbered box is a unique symbol. As rapidly as possible, the participant fills in the randomly ordered boxes with numbers paired with blank boxes with the symbol that corresponds to the number in the legend. The score is the total number of correctly entered symbols completed in 90 seconds (range, 0-133; higher score indicates better performance). Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Rey Auditory Verbal Learning Test (RAVLT)
The Rey Auditory Verbal Learning Test (RAVLT) was used to assess verbal memory. The participant is read a list of 15 words five times. After each time the list is given, the participant is asked to immediately recall as many words as possible. Following the fifth recall, an interference list is presented, after which the participant is asked to spontaneously recall words from the original list. After a 10-minute interval has passed, the participant is asked again to recall as many words as possible from the original list. The number of words correctly recalled on the delayed recall were used in the analysis (range, 0-15; higher number correct indicates better performance). Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Modified Stroop Color and Word Test
The Modified Stroop Color and Word Test was used to assess executive function. The test measures a participant's ability to view complex visual stimuli and to respond to one stimulus dimension while suppressing response to another competitive stimulation. The participant first reads aloud words denoting colors printed in black ink (Subtest 1), then names aloud the color of blocks printed in colored ink (Subtest 2), and finally names aloud the color ink in which the words are printed in which are incongruent to the word (Subtest 3). The amount of time to complete each subtest and the number of errors are recorded and interference calculated as time to complete Subtest 3 - Subtest 1 + errors (lower interference scores indicate better cognitive performance). Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
Modified Mini-Mental Status Exam (3MS)
The Modified Mini-Mental Status Exam (3MS) was used to assess global cognitive function. Scores range from 0 to 100 with higher scores indicating better cognitive function. Assessed 8 or 9 years post-randomization in Look AHEAD parent Study.
Time frame: Assessed 8 or 9 years post-randomization in Look AHEAD parent Study
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