Nia Mitchell

Positions:

Assistant Professor of Medicine

Medicine, General Internal Medicine
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

M.D. 2005

Washington University School of Medicine

M.P.H. 2010

University of Colorado School of Medicine

Internal Medicine Residency

University of Colorado School of Medicine

Primary Care Research Fellowship

University of Colorado School of Medicine

Grants:

Changes in Weight and Physical Function for Older African American Women in National, Peer-Led, Community-Based Weight Loss Program

Administered By
Medicine, General Internal Medicine
Awarded By
National Institutes of Health
Role
Principal Investigator
Start Date
End Date

Evaluation of Low Cost National Weight Loss Program in Underserved

Administered By
Medicine, General Internal Medicine
Awarded By
National Institutes of Health
Role
Principal Investigator
Start Date
End Date

Changes in Weight and Physical Function for Older African American Women in National, Peer-Led, Community-Based Weight Loss Program

Administered By
Medicine, General Internal Medicine
Awarded By
National Institutes of Health
Role
Principal Investigator
Start Date
End Date

Changes in Weight and Physical Function for Older African American Women in National, Peer-Led, Community-Based Weight Loss Program

Administered By
Medicine, General Internal Medicine
Awarded By
National Institutes of Health
Role
Principal Investigator
Start Date
End Date

Publications:

Retrospective cohort study of changes in estimated glomerular filtration rate for patients prescribed a low carb diet.

PURPOSE OF REVIEW: Obesity and diabetes contribute to chronic kidney disease (CKD) and accelerate the loss of kidney function. Low carbohydrate diets (LCDs) are associated with weight loss and improved diabetes control. Compared to the typical Western diet, LCDs contain more protein, so individuals with CKD are not included in studies of LCDs. Therefore, there are no studies of LCDs for weight loss and their effects on kidney function. RECENT FINDINGS: Obesity, hyperglycemia, and hyperinsulinemia can be detrimental to kidney function. LCDs may improve kidney function in patients with obesity and diabetes because they are associated with weight loss, improve blood sugar control, and decrease endogenous insulin production and exogenous insulin requirements. SUMMARY: In this study, for patients with mildly reduced and moderately to severely reduced kidney function who were prescribed an LCD, their estimated glomerular filtration rate (eGFR) was either unchanged or improved. For those with normal or elevated eGFR, their kidney function was slightly decreased. For those without diabetes, greater weight loss was associated with improved eGFR. Future studies should prospectively measure low carbohydrate dietary adherence and physical activity and directly measure changes in GFR and albuminuria for participants with CKD before and during that diet.
Authors
Mitchell, NS; Batch, BC; Tyson, CC
MLA Citation
Mitchell, Nia S., et al. “Retrospective cohort study of changes in estimated glomerular filtration rate for patients prescribed a low carb diet.Curr Opin Endocrinol Diabetes Obes, vol. 28, no. 5, Oct. 2021, pp. 480–87. Pubmed, doi:10.1097/MED.0000000000000673.
URI
https://scholars.duke.edu/individual/pub1494312
PMID
34392262
Source
pubmed
Published In
Curr Opin Endocrinol Diabetes Obes
Volume
28
Published Date
Start Page
480
End Page
487
DOI
10.1097/MED.0000000000000673

Predictors of long-term weight loss trajectories during a behavioral weight loss intervention: An exploratory analysis.

Background: Substantial interindividual variability in response to behavioral weight loss interventions remains a critical challenge in obesity treatment. An improved understanding of the complex factors that contribute to this variability may improve obesity treatment outcomes. Objective: To identify weight change trajectories during a behavioral weight loss intervention and to explore differences between trajectory groups in sociodemographic, biologic, behavioral, and psychosocial factors. Methods: Adults (n = 170, 40 ± 9 years, BMI 34 ± 4 kg/m2, 84% female) participated in an 18-month behavioral weight loss intervention. Weight was measured at 0, 3, 6, 9, 12, 15, 18, and 24 months. Among participants with at least two weights after baseline (n = 140), clusters of longitudinal trajectories of changes in weight were identified using a latent class growth mixture model. The association between baseline factors or changes in factors over time and trajectory group was examined. Results: Two weight change trajectories were identified: "weight regainers" (n = 91) and "weight loss maintainers" (n = 49). Black participants (90%, 19/21) were more likely than non-Black participants to be regainers versus maintainers (p < 0.01). Maintainers demonstrated greater increases in device-measured physical activity, autonomous motivation for exercise, diet self-efficacy, cognitive restraint, and engagement in weight management behaviors and greater reductions in barriers for exercise, disinhibition, and depressive symptoms over 24 months versus regainers (p < 0.05). Conclusion: Maintainers and regainers appear to be distinct trajectories that are associated with specific sociodemographic, behavioral, and psychosocial factors. Study results suggest potential targets for more tailored, multifaceted interventions to improve obesity treatment outcomes.
Authors
Ostendorf, DM; Blankenship, JM; Grau, L; Arbet, J; Mitchell, NS; Creasy, SA; Caldwell, AE; Melanson, EL; Phelan, S; Bessesen, DH; Catenacci, VA
MLA Citation
Ostendorf, Danielle M., et al. “Predictors of long-term weight loss trajectories during a behavioral weight loss intervention: An exploratory analysis.Obes Sci Pract, vol. 7, no. 5, Oct. 2021, pp. 569–82. Pubmed, doi:10.1002/osp4.530.
URI
https://scholars.duke.edu/individual/pub1485150
PMID
34631135
Source
pubmed
Published In
Obesity Science & Practice
Volume
7
Published Date
Start Page
569
End Page
582
DOI
10.1002/osp4.530

Outpatient metformin use is associated with reduced severity of COVID-19 disease in adults with overweight or obesity.

Observational studies suggest outpatient metformin use is associated with reduced mortality from coronavirus disease-2019 (COVID-19). Metformin is known to decrease interleukin-6 and tumor-necrosis factor-α, which appear to contribute to morbidity in COVID-19. We sought to understand whether outpatient metformin use was associated with reduced odds of severe COVID-19 disease in a large US healthcare data set. Retrospective cohort analysis of electronic health record (EHR) data that was pooled across multiple EHR systems from 12 hospitals and 60 primary care clinics in the Midwest between March 4, 2020 and December 4, 2020. Inclusion criteria: data for body mass index (BMI) > 25 kg/m2 and a positive SARS-CoV-2 polymerase chain reaction test; age ≥ 30 and ≤85 years. Exclusion criteria: patient opt-out of research. Metformin is the exposure of interest, and death, admission, and intensive care unit admission are the outcomes of interest. Metformin was associated with a decrease in mortality from COVID-19, OR 0.32 (0.15, 0.66; p = .002), and in the propensity-matched cohorts, OR 0.38 (0.16, 0.91; p = .030). Metformin was associated with a nonsignificant decrease in hospital admission for COVID-19 in the overall cohort, OR 0.78 (0.58-1.04, p = .087). Among the subgroup with a hemoglobin HbA1c available (n = 1193), the adjusted odds of hospitalization (including adjustment for HbA1c) for metformin users was OR 0.75 (0.53-1.06, p = .105). Outpatient metformin use was associated with lower mortality and a trend towards decreased admission for COVID-19. Given metformin's low cost, established safety, and the mounting evidence of reduced severity of COVID-19 disease, metformin should be prospectively assessed for outpatient treatment of COVID-19.
Authors
Bramante, CT; Buse, J; Tamaritz, L; Palacio, A; Cohen, K; Vojta, D; Liebovitz, D; Mitchell, N; Nicklas, J; Lingvay, I; Clark, JM; Aronne, LJ; Anderson, E; Usher, M; Demmer, R; Melton, GB; Ingraham, N; Tignanelli, CJ
MLA Citation
Bramante, Carolyn T., et al. “Outpatient metformin use is associated with reduced severity of COVID-19 disease in adults with overweight or obesity.J Med Virol, vol. 93, no. 7, July 2021, pp. 4273–79. Pubmed, doi:10.1002/jmv.26873.
URI
https://scholars.duke.edu/individual/pub1474863
PMID
33580540
Source
pubmed
Published In
J Med Virol
Volume
93
Published Date
Start Page
4273
End Page
4279
DOI
10.1002/jmv.26873

The degree of engagement of overweight/obese adult women in the recommended activities of the Chilean "Vida Sana" program is directly correlated with its effectiveness.

Introduction: Introduction: the Chilean Ministry of Health implements the Vida Sana (VS) program with the objective of reducing risk factors for chronic diseases in overweight/obese (OW/OB) individuals, aged 2-64. Objective: to determine the effectiveness of VS in OW/OB women (20-44 yrs) in terms of their engagement in the recommended activities. These consist of participating in a minimum number each of three core activities (psychologist consultations, lifestyle workshops, and physical activity sessions) during 6 months, to obtain a 5 % weight loss and improved physical fitness (PF). Methods: a retrospective study involving secondary analyses of the 2017 VS database (n = 5,179 OW/OB women). We determined effectiveness by: a) comparing changes in weight and PF in participants who achieved one or both outcomes, using t-tests and tests of proportions, and b) assessing the probability of achieving the program´s goal, according to participation in 1, 2, or 3 core activities, individually and jointly, using the OR (95 % CI) and trend analysis. Results: around 32 %, 88 %, and 29 % of women achieved 5 % weight loss, improved PF, and both, respectively. The high percentage of women who improved PF was due to a permissive criterion. Although 20 % of women attained the program´s goal with 0 engagement, among participants, the ORs (95 % CI) for achieving the program´s goal when engaging in 1, 2, or 3 core activities were 1.55 (CI 1.2-2.03), 2.34 (1.76-3.11), and 3.5 (2.21-5.53), respectively. Conclusion: effectiveness parallels degree of engagement in the recommended activities of VS. A characterization of a program´s participation rate is crucial for improving its effectiveness.
Authors
Mellado Peña, F; Mitchell, NS; Leyton Dinamarca, B; Kain Berkovic, J
MLA Citation
Mellado Peña, Fernanda, et al. “The degree of engagement of overweight/obese adult women in the recommended activities of the Chilean "Vida Sana" program is directly correlated with its effectiveness.Nutr Hosp, vol. 38, no. 4, July 2021, pp. 807–13. Pubmed, doi:10.20960/nh.03461.
URI
https://scholars.duke.edu/individual/pub1476064
PMID
33703910
Source
pubmed
Published In
Nutr Hosp
Volume
38
Published Date
Start Page
807
End Page
813
DOI
10.20960/nh.03461

Continuous Engagement in a Weight-Loss Program Promotes Sustained Significant Weight Loss.

BACKGROUND: Significant weight loss improves health but regain is common. OBJECTIVE: The objective of the study was to determine if 2,346 members of Take Off Pounds Sensibly-a national, low-cost, peer-led weight-loss program-achieved and maintained significant weight loss with 7 consecutive annual renewals. METHODS: This study was a retrospective cohort design. For each renewal, the cumulative change from baseline weight was calculated. Weight change was placed into 1 of 3 categories: significant weight loss, loss ≥ 5%; weight stable, loss of 0 to < 5%; or weight gain, any amount above baseline weight. RESULTS: The cohort included 2,346 individuals. Fifty-one percent (n=740) of participants were in the significant weight-loss category all 7 years; 256 (18%) were in the significant weight-loss category at year 1 but moved into at least 1 other category during years 2 through 6; 359 (25%) were in the weight stable category at year 1; and 98 (7%) were in the weight gain category at year 1. CONCLUSIONS: Over 60% of the population achieved significant weight loss by year 7. Since continuous, long-term engagement in a weight-loss program can lead to significant weight loss, even if significant weight loss is not initially achieved, participation should be encouraged.
Authors
Mitchell, NS; Seyoum, EA; Bhavsar, NA; Webb, FJ
MLA Citation
Mitchell, Nia S., et al. “Continuous Engagement in a Weight-Loss Program Promotes Sustained Significant Weight Loss.Wmj, vol. 119, no. 4, Dec. 2020, pp. 253–57.
URI
https://scholars.duke.edu/individual/pub1471248
PMID
33428835
Source
pubmed
Published In
Wmj
Volume
119
Published Date
Start Page
253
End Page
257