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Effects of Obesity, Weight Loss, and Physical Activity on Brain Structure and Cognition

Collins, Audrey M (2022) Effects of Obesity, Weight Loss, and Physical Activity on Brain Structure and Cognition. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Obesity in adults has been linked to altered brain gray matter volume and cognitive function. Weight loss may positively influence these aspects of brain health. However, evidence is inconsistent due to small sample sizes, short intervention lengths, and varying modes of treatment. Individual intervention components, such as physical activity, may influence gray matter volume and cognitive function differently. Data evaluating these relationships in the middle of the lifespan is lacking. Purpose: The purpose of this secondary analysis was to assess the associations between body weight, physical activity (PA), bilateral gray matter volume, and working memory in inactive adults with overweight or obesity participating in a 12-month behavioral weight loss intervention. Methods: Participants (N=115, Age=48 years [IQR: 42,52], BMI=32.4 kg/m2 [IQR: 29.0, 35.4]) were randomized to DIET, DIET + MOD-PA, or DIET + HIGH-PA. All groups were prescribed a reduced-calorie diet (1200-1800 kcal/day) and behavioral intervention. DIET + MOD-PA and DIET + HIGH-PA groups were prescribed 150 min/week of moderate-to-vigorous PA (MVPA) and 250 min/week of MVPA, respectively. MET-min/wk of light-intensity PA (LPA) and MVPA were measured objectively. Working memory (reaction time (RT), accuracy (ACC)) was evaluated by the N-Back Task. Bilateral gray matter volumes (mm3) of the hippocampus and basal ganglia were measured using 3T MRI and calculated using FSL segmentation algorithms. Results: At baseline, LPA was inversely associated with percent ACC difference (one-back subtracted from two-back) (β=-.003, p=.021), while MVPA was associated with absolute (β=-3.26e-05, p=.016) and percent (β=-.003, p=.038) ACC difference. Higher volume of MVPA was associated with bilateral nucleus accumbens volume (β=.044, p=008). Across the intervention, there were significant reductions in weight, one-back RT, two-back RT, with significant increases in volumes of LPA and MVPA. Weight loss was inversely associated with bilateral pallidum volume (β=-5.95, p=.046). Change in LPA was associated with changes in both absolute (β=-.027, p=.025) and percent (β=-.003, p=.043) RT difference and absolute (β=-5.51e-05, p=.005) and percent (β=-.004, p=.026) ACC difference. Conclusion: Weight loss and PA may have a small influence on gray matter volume and working memory in middle-aged adults with overweight or obesity without other chronic health concerns.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Collins, Audrey Mamc234@pitt.eduamc2340000-0002-9246-2258
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairJakicic, John
Committee MemberAmbrosio,
Committee MemberErickson, Kirk
Committee MemberLevine, Michele
Date: 10 January 2022
Date Type: Publication
Defense Date: 30 September 2021
Approval Date: 10 January 2022
Submission Date: 20 December 2021
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 136
Institution: University of Pittsburgh
Schools and Programs: School of Education > Health and Physical Activity
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: behavioral weight loss intervention, standard weight loss intervention, light-intensity physical activity, moderate-to-vigorous physical activity, exercise, obesity, gray matter volume, cognition, working memory
Date Deposited: 10 Jan 2022 18:18
Last Modified: 10 Jan 2022 18:18


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