Bio


Shawna Follis, PhD, MS, is a postdoctoral research fellow at the Stanford Prevention Research Center. Dr. Follis is a social epidemiologist researching social determinants of health, race/ethnic health disparities, body composition, and aging.

Honors & Awards


  • Aetna Award for Excellence in Research on Older Women and Public Health, American Public Health Association (October 2020)

Professional Education


  • Doctor of Philosophy, University of Arizona (2020)
  • Master of Science, Purdue University (2014)
  • Bachelor of Arts, Indiana-Purdue University, Fort Wayne (2012)

2021-22 Courses


All Publications


  • MRI based validation of abdominal adipose tissue measurements from DXA in postmenopausal women. Journal of clinical densitometry : the official journal of the International Society for Clinical Densitometry Bea, J. W., Chen, Z., Blew, R. M., Nicholas, J. S., Follis, S., Bland, V. L., Cheng, T. D., Ochs-Balcom, H. M., Wactawski-Wende, J., Banack, H. R., Neuhouser, M. L., Laddu, D., Stefanick, M. L., Cauley, J. A., Caan, B., LeBoff, M. S., Chlebowski, R. T., Odegaard, A. O. 2021

    Abstract

    INTRODUCTION: Visceral adipose tissue (VAT) is a hypothesized driver of chronic disease. Dual-energy X-ray absorptiometry (DXA) potentially offers a lower cost and more available alternative compared to gold-standard magnetic resonance imaging (MRI) for quantification of abdominal fat sub-compartments, VAT and subcutaneous adipose tissue (SAT). We sought to validate VAT and SAT area (cm2) from historical DXA scans against MRI.METHODOLOGY: Participants (n = 69) from the Women's Health Initiative (WHI) completed a 3 T MRI scan and a whole body DXA scan (Hologic QDR2000 or QDR4500; 2004-2005). A subset of 43 participants were scanned on both DXA devices. DXA-derived VAT and SAT at the 4th lumbar vertebrae (5 cm wide) were analyzed using APEX software (v4.0, Hologic, Inc., Marlborough, MA). MRI VAT and SAT areas for the corresponding DXA region of interest were quantified using sliceOmatic software (v5.0, Tomovision, Magog, Canada). Pearson correlations between MRI and DXA-derived VAT and SAT were computed, and a Bland-Altman analysis was performed.RESULTS: Participants were primarily non-Hispanic white (86%) with a mean age of 70.51 ± 5.79 years and a mean BMI of 27.33 ± 5.40 kg/m2. Correlations between MRI and DXA measured VAT and SAT were 0.90 and 0.92, respectively (p ≤ 0.001). Bland-Altman plots showed that DXA-VAT slightly overestimated VAT on the QDR4500 (-3.31 cm2); this bias was greater in the smaller subset measured on the older DXA model (QDR2000; -30.71 cm2). The overestimation of DXA-SAT was large (-85.16 to -118.66 cm2), but differences were relatively uniform for the QDR4500.CONCLUSIONS: New software applied to historic Hologic DXA scans provide estimates of VAT and SAT that are well-correlated with criterion MRI among postmenopausal women.

    View details for DOI 10.1016/j.jocd.2021.07.010

    View details for PubMedID 34404568

  • The intersectional role of social stress in fracture risk: results from the Women's Health Initiative. Journal of epidemiology and community health Follis, S., Klimentidis, Y. C., Bea, J., Hu, C., Garcia, D., Wactawski-Wende, J., Kohler, L., Shadyab, A. H., Flores, M., Tindle, H. A., Chen, Z. 2021

    Abstract

    BACKGROUND: The biological consequences of stress from the social environment pattern health outcomes. This study investigated whether social stress is prospectively associated with fracture incidence among racially and ethnically diverse, postmenopausal women.METHODS: Data from 160 709 postmenopausal women in the Women's Health Initiative was analysed using Cox proportional hazards regression models to examine prospective associations of social stress with time to total and hip fracture incidence. Self-reported questionnaires measuring social strain, social functioning and social support were used to assess social stress.RESULTS: Age and race/ethnicity modified associations between social stress and total and hip fractures. HRs for the associations between higher social support (indicating lower social stress) and total fractures among those age 50-59 years were 0.92 (95% CI: 0.90 to 0.94); HR=0.94 (95% CI: 0.93 to 0.95) for those age 60-69 years and HR=0.96 (95% CI: 0.95 to 0.98) for those age 70-79 years. Higher social strain was associated with greater hip fracture incidence among Native American women (HR=1.84, 95% CI: 1.10 to 3.10), Asian women (HR=1.37, 95% CI: 1.01 to 1.86) and white women (HR=1.04, 95% CI: 1.01 to 1.08).CONCLUSION: Identifying population patterns of fracture incidence as biological expressions of social environments reveals how race/ethnic specific social environmental factors influence disparities in fractures.

    View details for DOI 10.1136/jech-2020-216354

    View details for PubMedID 34039659

  • Comparison of Wearable Sensor to Traditional Methods in Functional Outcome Measures: A Systematic Review. Journal of orthopaedic research : official publication of the Orthopaedic Research Society Follis, S., Chen, Z., Mishra, S., Howe, C. L., Toosizadeh, N., Dohm, M. 2020

    Abstract

    Traditional methods of collecting functional outcome measures are widely used for lower extremity arthroplasty outcome assessment. Wearable sensors are emerging as viable tools for functional outcome measures in monitoring of post-arthroplasty recovery. The objective of this review was to compare the efficacy of wearable sensors with traditional methods for monitoring post-arthroplasty functional recovery. Articles were searched for inclusion in this review that used both traditional and wearable sensor functional outcome measures to assess lower-extremity function before and after lower extremity arthroplasty. Two independent screeners reviewed all articles, and resolved differences through consensus and consultation with the senior author. Studies that met inclusion criteria were evaluated for methodologic quality using performed risk of bias assessments. Results from several traditional and wearable sensor functional outcome measures from baseline through follow-up were normalized across studies. Fourteen articles met inclusion criteria. Six studies used statistical methods to directly compare functional outcome measures, and eight studies used qualitative description of comparisons. This review found evidence that wearable sensors detected nuanced functional outcome information on the specific biomechanics and timing of recovery, which were unaccounted for using traditional methods.Wearable sensors have shown promising utility in providing additional recovery information from lower extremity arthroplasty compared with traditional functional outcome measures, but future research is needed to assess the clinical significance of this additional information. Wearable sensor technology is an emerging clinical tool providing advanced and determinative data with the potential for advancing assessment of lower extremity arthroplasty outcomes. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/jor.24950

    View details for PubMedID 33300119

  • Psychosocial stress and bone loss among postmenopausal women: results from the Women's Health Initiative JOURNAL OF EPIDEMIOLOGY AND COMMUNITY HEALTH Follis, S. L., Bea, J., Klimentidis, Y., Hu, C., Crandall, C. J., Garcia, D. O., Shadyab, A. H., Nassir, R., Chen, Z. 2019; 73 (9): 888–92

    Abstract

    Bone loss is a major public health concern with large proportions of older women experiencing osteoporotic fractures. Previous research has established a relationship between psychosocial stressors and fractures. However, few studies have investigated bone loss as an intermediary in this relationship. This study investigates whether social stress is associated with bone loss during a 6-year period in postmenopausal women.Data from 11 020 postmenopausal women from the USA was used to examine self-reported psychosocial stress in relation to change in bone mineral density (BMD) measured at the femoral neck, lumbar spine and total hip. Linear regression models were used to examine associations between social measures of psychosocial stress (social strain, social functioning and social support) and per cent change in BMD over 6 years.High social stress was associated with decreased BMD over 6 years. After adjustment for confounders, each point higher in social strain was associated with 0.082% greater loss of femoral neck BMD, 0.108% greater loss of total hip BMD and 0.069% greater loss of lumbar spine BMD (p<0.05). Low social functioning and low social support were associated with greater decreases in femoral neck BMD, and low social functioning was associated with greater decreases in total hip BMD.The findings provide evidence for an association between high social stress and greater bone loss over 6 years of follow-up. In agreement with the prior literature, the findings for social strain and social functioning suggest that poor quality of social relationships may be associated with bone loss in postmenopausal women.

    View details for DOI 10.1136/jech-2019-212516

    View details for Web of Science ID 000490193000016

    View details for PubMedID 31289118

  • Reply to Effects of Hormone Replacement Therapy on Sarcopenia: Is It Real? JOURNAL OF THE AMERICAN GERIATRICS SOCIETY Follis, S., Bea, J. W., Cauley, J. A., Shadyab, A. H., Cook, A., Chen, Z. 2019; 67 (6): 1298–99

    View details for DOI 10.1111/jgs.15805

    View details for Web of Science ID 000471133600034

    View details for PubMedID 30697691

  • Association Between Sarcopenic Obesity and Falls in a Multiethnic Cohort of Postmenopausal Women JOURNAL OF THE AMERICAN GERIATRICS SOCIETY Follis, S., Cook, A., Bea, J. W., Going, S. B., Laddu, D., Cauley, J. A., Shadyab, A. H., Stefanick, M. L., Chen, Z. 2018; 66 (12): 2314–20

    View details for DOI 10.1111/jgs.15613

    View details for Web of Science ID 000454532800014

  • Association Between Sarcopenic Obesity and Falls in a Multiethnic Cohort of Postmenopausal Women. Journal of the American Geriatrics Society Follis, S., Cook, A., Bea, J. W., Going, S. B., Laddu, D., Cauley, J. A., Shadyab, A. H., Stefanick, M. L., Chen, Z. 2018

    Abstract

    OBJECTIVES: To investigate associations between sarcopenia, obesity, and sarcopenic obesity and incidence of falls in a racially and ethnically diverse cohort of healthy postmenopausal women.DESIGN: Prospective cohort study.SETTING: Three Women's Health Initiative (WHI) clinical centers (Tucson-Phoenix, AZ; Pittsburgh, PA; Birmingham, AL).PARTICIPANTS: Postmenopausal women aged 50 to 79 enrolled in the WHI who underwent bone and body composition scans using dual-energy x-ray absorptiometry at baseline (N = 11,020).MEASUREMENTS: Sarcopenia was defined as the lowest 20th percentile of appendicular lean mass, correcting for height and body fat. Obesity was defined as a body fat percentage greater than 42%. Sarcopenic obesity was defined as co-occurrence of sarcopenia and obesity. The fall outcome was defined as falling 2 or more times in any year during 7 years of follow-up. The risk of falls associated with sarcopenic obesity were analyzed using log binomial regression models stratified according to age and race/ethnicity.RESULTS: Sarcopenic obesity was associated with greater risk of falls in women aged 50 to 64 (relative risk (RR) = 1.35, 95% confidence interval (CI)=1.17-1.56) and 65 to 79 (RR = 1.21, 95% CI=1.05-1.39). Sarcopenic obesity related fall risk was higher in Hispanic women (RR = 2.40, 95% CI=1.56-3.67) than non-Hispanic white women (RR = 1.24, 95% CI=1.11-1.39).CONCLUSION: In a multiethnic cohort of postmenopausal women, sarcopenic obesity-related fall risk was high in women younger than 65 and those age 65 and older. Sarcopenic obesity posed the highest risk for falls in Hispanic women. The findings support identification of causal factors and health disparities in sarcopenic obesity to customize fall prevention strategies and ameliorate this significant public health burden.

    View details for PubMedID 30375641