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Michelle D. Shardell, PhD

Academic Title:


Primary Appointment:

Epidemiology & Public Health

Administrative Title:

Vice Chair of Research, Epidemiology & Public Health

Additional Title:



Institute for Genome Sciences Health Sciences Facilities III, #3183 670 W Baltimore Street Baltimore, Maryland 21201

Phone (Primary):


Education and Training

B.S.           University of Florida, Mathematics (with High Honors)

M.S.          University of Michigan School of Public Health, Biostatistics

Ph.D.         Johns Hopkins University Bloomberg School of Public Health, Biostatistics



I am a biostatistician with a history of NIA funding who cross-fertilizes biostatistical expertise and aging research. My interdisciplinary biostatistics in aging research includes refining structural models to assess the relation of blood biomarkers with aging-related outcomes, developing novel statistical methods to handle survival bias and unmeasured confounding in studies of older adults, adapting machine-learning methods in harmonized-data projects, using machine-learning methods to identify and validate clinically meaningful thresholds, treating the use of proxy respondents as a missing-data problem, combining epidemiologically rigorous methods with -omics data, and developing time-to-event methods with informative censoring.  


I have authored or co-authored over 200 peer-reviewed publications in leading journals including research on aging-related functional decline; novel aging-related statistical methods; development of SAS and R software modules; high-dimensional biomarkers (metabolomics, proteomics, microbiome); and manuscripts as part of the FNIH Biomarkers Consortium project, where I served as lead biostatistician pooling, harmonizing and analyzing existing archived data from 9 cohorts. I served as PI of PRoject on Optimal VItamin D in Older adults (PROVIDO), an NIA-funded R01 aiming to identify and validate sex-specific threshold concentrations of 25-hydroxyvitamin D for physical function in older adults. Additionally, I was a member of the first cohort of the “Next Generation of AD/ADRD Researchers,” an NIA-funded R03 mechanism; and I am currently the PI of multiple NIH-funded R01-equivalent projects and co-director of the Biostatistics and Informatics Core within UMB's Claude D. Pepper Older Americans Independence Center. In addition to my scholarship, I am active in biostatistics education, outreach, and service to multiple professional societies.  

Please see my GitHub for code from my research projects:

Research/Clinical Keywords

Biostatistics, Epidemiology, Gerontology, Aging Research, Geroscience, Microbiome

Highlighted Publications

Shen B, Ren H, Shardell M, Falvey, J, Chen C*. Analyzing risk factors for post-acute recovery in older adults with Alzheimer's disease and related dementia: a new semi-parametric model for large-scale Medicare claims. Statistics in Medicine, in press.


Shardell M, Cappola AR, Guralnik JM, Hicks GE, Kritchevsky SB, Simonsick EM, Ferrucci L, Semba RD, Chiles Shaffer N, Harris T, Eiriksdottir G, Gudnason V, Cotch MF, Ensrud KE, Cawthon PM. Sex-specific 25-hydroxyvitamin D threshold concentrations for functional outcomes in older adults: Project on Optimal Vitamin D in Older Adults (PROVIDO). Am J Clin Nutr 2021 114:16-28. 


Mirzayi C, Renson A, Genomic Standards Consortium, Massive Analysis and Quality Control Society,…Shardell M,…Jones HE, Waldron L. Reporting guidelines for human microbiome research: the STORMS checklist. Nature Medicine 2021 27:1885-92. 


Shardell M, Gravitt PE, Burke AE, Ravel J, Brotman RM. Association of vaginal microbiota with signs and symptoms of the genitourinary syndrome of menopause across reproductive stages. J Gerontol Series A: Med Sci Biol Sci 2021 76:1542-50.  [invited for a special issue on the intersection of reproductive and aging biology].


Shardell M, Ferrucci L. Joint mixed-effects models for causal inference with longitudinal data. Statistics in Medicine 2018 37:829-846.


Shardell M, Ferrucci L. Instrumental variable analysis of multiplicative models with potentially invalid instruments. Statistics in Medicine 2016 35:5430-5447.


Shardell M, Hicks GE, Ferrucci L. Doubly robust estimation and causal inference in longitudinal studies with dropout and truncation by death. Biostatistics 2015 16:155-168.


Additional Publication Citations

Tian Q, Shardell MD, Kuo P, Tanaka T, Simonsick EM, Moaddel R, Resnick SM, Ferrucci L. Plasma metabolomic signatures of dual decline in memory and gait in older adults. Geroscience 2023 45:2659-67.


Kuo P-L, Schrack JA, Levine ME, Shardell MD, Simonsick EM, Chia CW, Moore AZ, Tanaka T, An Y, Karikkineth A, AlGhatrif, Elango E, Zuckley LM, Egan JM, de Cabo R, Resnick SM, Ferrucci L. Longitudinal Phenotypic Aging Metrics in the Baltimore Longitudinal Study of Aging. Nature Aging 2022 2:635-43. 


Magaziner J, Mangione KK, Orwig D, Baumgarten M, Mager L, Terrin M, Fortinsky RH, Gruber-Baldini AL, Beamer BA, Tosteson ANA, Kenny AM, Shardell M, Binder EF, Koval K, Resnick B, Miller R, Forman S, McBride R, Craik RL. Effect of a multicomponent home-based physical therapy intervention on ambulation after hip fracture in older adults: The CAP Randomized Clinical Trial. JAMA 2019 322:946-956.


Kapogiannis D, Mustapic M, Shardell MD, Berkowitz ST, Diehl TC, Spangler RD, Tran J, Lazaropoulos MP, Chawla S, Gulyani S, Eitan E, An Y, Huang CW, Oh ES, Lyketsos CG, Resnick SM, Goetzl EJ, Ferrucci L. Extracellular vesicle biomarkers predict Alzheimer’s Disease in the Baltimore Longitudinal Study of Aging. JAMA Neurology 2019 76:1340-51.


Shardell M, Hicks GE. Statistical analysis with missing exposure data measured by proxy respondents: a misclassification problem within a missing-data problem. Statistics in Medicine 2014 33:4437-4452.


Shardell M, Simonsick E, Hicks GE, Resnick B, Ferrucci L, Magaziner J. Sensitivity analysis for nonignorable missingness and outcome misclassification from proxy reports. Epidemiology 2013 24:215-223.


Harris AD, Pineles L, Belton B, Johnson JK, Shardell M, Loeb M, Newhouse R, Dembry L, Braun B, Perencevich EN, Hall KK, Morgan DJ, and the Benefits of Universal Glove and Gown (BUGG) primary investigators. Universal glove and gown use and acquisition of antibiotic resistant bacteria in the ICU: A randomized trial. JAMA 2013 310:1571-1580.


Shardell M, Hicks GE, Miller RR, Magaziner J. Semiparametric Regression Models for Repeated Measures of Mortal Cohorts with Non-Monotone Missing Outcomes and Time-Dependent Covariates. Statistics in Medicine 2010 29:2282-2296


Shardell MD, El-Kamary SS. Calculating sample size for studies with expected all-or-none nonadherence and selection bias. Biometrics, 2009 65:635-639.

Awards and Affiliations

Professional Societies:

American Academy for the Advancement of Science

American Statistical Association

Eastern North American Region of the International Biometric Society

Gerontological Society of America


Highlighted Awards:

2006  Outstanding Teaching Award, Department of Epidemiology and Preventive                           Medicine, University of Maryland; Baltimore, Maryland

2017   Fellow, Gerontological Society of America

2020    Strategic Initiatives Award for best proposal for “Developing the Next Generation of             Biostatisticians,” American Statistical Association Biometrics Section

Grants and Contracts

02/27/23-08/31/27       (Principal Investigator)

Methods to Test Biomarkers of Aging as Shared Determinants of Alzheimer’s Disease and Related Dementias and Physical Disability (R01)

NIH/NIA  (R01 AG079854)


09/02/22-6/30/27       (Principal Investigator)

Statistical Methods for Kidney Markers as Shared Determinants of Dementia and Physical Disability in Older Adults (R01)

NIH/National Institute on Aging (R01 AG048069 Competitive Renewal)


08/18/22-6/30/25       (Principal Investigator)

Statistical Models and Mechanisms Linking Biomarkers of Aging to Cognitive-Physical Decline and Dementia (RF1)

NIH/NINDS  (RF1 NS128360)


9/01/21-8/31/26       (Contact Principal Investigator with R. Brotman)

Methods to Test the Role of Age-Related Lifestyle, Vaginal Microenvironment Changes and the Prevention, Treatment, and Progression of Genitourinary Syndrome of Aging (R01)

NIH/National Institute on Aging (R01 AG069915)


8/15/21-6/30/26     (Co-Director of the Biostatistics and Informatics Core) PI: J Magaziner/L Katzel/A Ryan)

University of Maryland Claude D Pepper Older Americans Independence Center (UM-OAIC) (P30)

NIH/National Institute on Aging (P30 AG028747)