IEFS Staff

IEFS Leadership

  • Martha J Shrubsole, Ph.D.

    Research Professor

    Dr. Martha Shrubsole is Research Professor in epidemiology at Vanderbilt University Medical Center and leads the International Epidemiology Field Station. A major focus of Dr. Shrubsole’s research is to identify modifiable factors for the prevention of colorectal neoplasia and breast cancer. She has contributed multiple publications towards understanding risk factors for serrated polyps and conventional colorectal adenomas. Additional areas of interest are nutrients and nutrient-gene interactions in the one-carbon metabolism pathway and unique inflammation biomarkers in colorectal carcinogenesis. She is also studying the gut microbiome as a modifiable factor. Dr. Shrubsole is also lead or key investigator in multiple US National Cancer Institute-funded clinical trials and other large epidemiologic studies.

  • Joanna Cabazares

    Health Services Research Analyst

    Joanna manages the organization of documents related to medical record acquisitions for the SCCS. She joined IEFS in 2003.

  • Katherine Cook

    Program Manager

    Katie supports the IEFS department and the ongoing research of the Southern Community Cohort Study. She joined IEFS in 2023.

  • Xijing Han

    Sr. Biostatistician

    Xijing provides statistical support for IEFS research projects. Her tasks include data management, statistical analyses, and scientific manuscript review. Xijing joined IEFS in 2009.

  • Carol Mayer

    Sr. Program Manager

    Carol enjoys her varied responsibilities managing the IEFS Maryland office and supporting the ongoing research of the Southern Community Cohort Study. She also administers the SCCS Publications Committee and manages the study website. Carol joined IEFS in 2014.

  • Michael Mumma


    Mike conducts data analysis for radiation studies and cancer research studies. He also conducts medical research for the SCCS and other studies using CMS Medicare/Medicaid data. Mike joined IEFS in 2000.

  • Heather Munro

    Sr. Biostatistician

    Heather provides statistical services for epidemiologic studies and has been involved with the Southern Community Cohort Study (SCCS) for over 10 years. She performs data analyses, data cleaning, number and dataset requests, and statistical reviews of SCCS manuscripts written by other investigators. Heather joined IEFS in 2005.

  • Joyce M Rohlsen-Karp

    Administrative Manager

    Michelle’s greatest joy is learning, being involved with and gaining knowledge about conducting research studies and respectfully interacting with our study participants for the past 15 years.  She works with the IEFS team on various research study projects and engages in and handles general office-related administrative tasks for the IEFS office in Jacksonville, Florida. Michelle joined IEFS in 2002.

  • Scott Shipe

    Senior Systems Administrator

    Scott handles the IT infrastructure for both IEFS offices. His primary role is to maintain a secure and efficient IT environment for IEFS research studies.  Scott is experienced in installing, upgrading, and replacing servers and other network infrastructure. He enjoys working with the IEFS team and ensuring that all IT systems are running smoothly. Scott joined IEFS in 2007.

  • Mark Steinwandel

    Principal IT Project Manager

    Mark manages numerous aspects of the SCCS including creation and distribution of study datasets, active and passive follow-up of study participants, statistical review of SCCS manuscripts, and adherence to study protocols. He also is the primary contact for SCCS and outside investigators who seek to access study resources. Mark is also involved in several SCCS spinoff ancillary studies. Mark joined IEFS in 2001.