Epidemiology & Public Health
Institute for Genome Sciences Health Sciences Facilities III, #3183 670 W Baltimore Street Baltimore, Maryland 21201
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 pooled-cohort projects, using machine-learning methods to identify clinically meaningful thresholds for sarcopenia and vitamin D deficiency, 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 175 peer-reviewed papers 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. Currently, I am the 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 am a member of the first cohort of the “Next Generation of AD/ADRD Researchers,” an NIA-funded R03 mechanism; and I am the PI of an NIA-funded R56 aiming to identify core vaginal microbiota associated with signs and symptoms of the genitourinary syndrome of menopause across reproductive stages. In addition to my scholarship, I am active in biostatistics education, outreach, and service to multiple professional societies.
Biostatistics, Epidemiology, Gerontology, Aging Research, Microbiome
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, in press.
Shardell M, Parimi N, Langsetmo L, Tanaka T, Jiang L, Orwoll E Shikany JM, Kado DM, Cawthon PM. Comparing analytical methods for the gut microbiome and aging: gut microbial communities and body weight in the Osteoporotic Fractures in Men (MrOS) Study. J Gerontol Series A: Med Sci Biol Sci 2020 75:1267-1275. [special issue on the microbiome & aging]
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.
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.
Brotman RM, Shardell MD, Gajer P, Fadrosh D, Chang K, Silver M, Viscidi RP, Burke AE, Ravel J, Gravitt PE. Association between the vaginal microbiota, menopause status and signs of vulvovaginal atrophy. Menopause 2014 21:450-458.
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 M, El-Kamary SS. Sensitivity analysis of informatively coarsened data using pattern mixture models. Journal of Biopharmaceutical Statistics, 2009 19:1018-1038.
Shardell MD, El-Kamary SS. Calculating sample size for studies with expected all-or-none nonadherence and selection bias. Biometrics, 2009 65:635-639.
American Statistical Association
Eastern North American Region of the International Biometric Society
Gerontological Society of America
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
9/30/15-4/30/21 (Principal Investigator)
Statistical Methods for Vitamin D Targets for Functional Outcomes in Older Adults (R01)
NIH/National Institute on Aging (R01 AG048069)
8/1/20-6/30/21 (Multiple Principal Investigator with J Magaziner)
Claude D. Pepper Older Americans Independence Center Supplement (P30)
NIH/National Institute on Aging (P30 AG028747-15S1)
9/30/20-8/31/21 (Contact Principal Investigator with R. Brotman)
Methods to Test Lifestyle, Vaginal Microenvironment and Genitourinary Symptoms across Menopause Transition (R56)
NIH/National Institute on Aging (R56 AG068673)
03/01/21-2/28/23 (Principal Investigator)
Epidemiology of the Inverse Comorbidity of Dementia and Cancer: Statistical Methods and Biological Mechanisms (R03)
NIH/National Institute on Aging (R03 AG070178)
4/1/11-3/31/15 (Principal Investigator)
Statistical Methods to Correct for Proxy Bias in Studies of Older Adults
NIH/National Institute on Aging (K25 AG034216)