Research Study 4, Research Brief 5, 2018

Mediators of Symptom Cluster and Employment in People with Multiple Sclerosis

by Kanako Iwanaga, Jia-Rung Wu, Xiangli Chen, Fong Chan, and Brian Phillips

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According to the National Multiple Sclerosis Society (NMSS), approximately 400,000 individuals are living with MS in the United States (NMSS, 2014). MS is a chronic illness of the central nervous system that impacts physical, psychological, and social functioning (Costa, Sa, & Calheiros, 2012; Tesar, Baumhackl, Kopp, & Gunther, 2003; Tortorella et al., 2014). MS symptoms have been studied in symptom clusters because they often co-occur and may have a compounding impact on an individual (Crayton & Rossman, 2006; Motl & McAuley, 2009; Motl, Suh, & Weikert, 2010). Symptom clusters are defined as “three or more concurrent symptoms (e.g., pain, fatigue, sleep insufficiency) that are related to each other” (Dodd et al., 2001, p. 465).

Due to the progressive, unpredictable, and disabling nature of MS and its associated symptoms, employment rates for individuals with MS are low (O’Connor, Cano, Thompson, & Playford., 2005). Employment is considered to be an important public health intervention for people with multiple sclerosis (MS). Individuals with MS who are employed, whether full or part-time, have better psychosocial and health outcomes than individuals who are not employed (Chiu et al., 2015). Given the evidence of the benefits of work and considering that symptom clusters have a significant impact on participation for persons with MS, it is important that we better understand the relationship between symptom clusters and employment.

Does Context Matter to the Relationship Between Symptom Severity and Employment?

In short, the answer is yes. Recent research on the World Health Organization’s (WHO) International Classification of Functioning (ICF) as a model for vocational rehabilitation (VR) demonstrates the importance of person-environment (P-E) contextual factors in mediating the effect of impairments on participation (Chan et al., 2009). The positive human traits factors of core self-evaluations (CSE) and social support are considered effective P-E contextual factors in ICF research (Smedema, Chan, et al., 2015; Smedema, Chan, & Phillips, 2014; Wilson et al., 2013). The purpose of this study was to evaluate CSE and social support as person-environment mediators for the relationship between symptom cluster and employment for persons with MS.


Participants for this study consisted of 154 people with MS at prime working age (25 – 54 years old). Participants were recruited by advertisements through monthly electronic newsletters and through a single round of direct email solicitation sent by National Multiple Sclerosis Society chapters to their members. Participants who completed the online survey received a $15.00 gift card upon completion of the study.


Figures 1 and 2 show that increased symptom clusters was related to increased odds of unemployment for people with multiple sclerosis. However, Figure 1 shows that core-self evaluations fully mediated this relationship. In other words, the influence of symptom clusters on employment can be explained by participants’ levels of core self-evaluations. Figure 2 shows that the relationship between symptom clusters and unemployment, although still significant, was less so when mediated by social support.

Figure 1
Path Coefficients for Simple Mediation Analysis on Employment Status (N = 154)

Note. Dotted line denotes the effect of MS symptom on employment status when CSE is not included as a mediator. b, c and c’ are unstandardized logistic regression coefficients, a is an unstandardized ordinary least squares (OLS) regression coefficient.
*p < .05, **p < .01, ***p < .001

Figure 2
Path Coefficients for Simple Mediation Analysis on Employment Status (N = 154)

Note. Dotted line denotes the effect of MS symptom on employment status when social support is not included as a mediator. b, c and c’ are unstandardized logistic regression coefficients, a is an unstandardized ordinary least squares (OLS) regression coefficient.
*p < .05, **p < .01, p*** < .001.


Findings suggest that both core self-evaluations and social support play an important role in the employment of people with MS, regardless of symptom severity. Together, increasing both CSE and social support will reduce the adverse impact of MS symptom cluster on employment outcome. Therefore, CSE and social support can be viewed as protective factors for maintaining employment in MS.


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Chiu, C. Y., Chan, F., Sharp, S. E., Dutta, A., Hartman, E., & Bezyak, J. (2015). Employment as a health promotion intervention for persons with multiple sclerosis. WORK: A Journal of Prevention, Assessment & Rehabilitation, 52, 749-756.

Costa, D. C., Sá, M. J., & Calheiros, J. M. (2012) The effect of social support on the quality of life of patients with multiple sclerosis. 70(2), 108-113. doi:10.1590/S0004-282X2012000200007

Crayton, H. J., & Rossman, H. S. (2006). Managing the symptoms of multiple sclerosis: A multimodal approach. Clinical Therapeutics, 28(4), 445-460.

Dodd, M. J., Miaskowski, C., Paul, S. M. (2001) Symptom clusters and their effect on the functional status of patients with cancer. Oncology Nursing Forum, 28, 465-470.

Motl, R. W., & McAuley, E. (2009). Symptom cluster as a predictor of physical activity in multiple sclerosis: Preliminary evidence. Journal of Pain and Symptom Management, 38, 270-280.

Motl, R. W., Suh, Y., & Weikert, M. (2010). Symptom Cluster and Quality of Life in Multiple Sclerosis. Journal of Pain and Symptom Management, 39(6), 1025-1032.

National Multiple Sclerosis Society. What is MS? (2014). Retrieved from

O'Connor, R., Cano, S., Thompson, A., & Playford, E. (2005). Factors influencing work retention for people with multiple sclerosis. Journal of Neurology, 252(8), 892-896.

Smedema, S. M., Chan, F., Yaghmaian, R. A., Cardoso, E. D., Muller, V., Keegan, J., … Ebener, D. J. (2015). The Relationship of Core Self-Evaluations and Life Satisfaction in College Students with Disabilities: Evaluation of a Mediator Model. Journal of Postsecondary Education and Disability, 28(3), 341-358.

Smedema, S., Chan, J., & Phillips, B. (2014). Core self-evaluations and Snyder’s hope theory in persons with spinal cord injuries. Rehabilitation Psychology, 59(4), 399-406.

Tesar, N., Baumhackl, U., Kopp, M., & Günther, V. (2003). Effects of psychological group therapy in patients with multiple sclerosis. Acta Neurologica Scandinavica, 107(6), 394-399.
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Wilson, L., Catalano, D., Sung, C., Phillips, B., Chou, C. C., Chan, Y.C., & Chan, F. (2013). Attachment, social support, and coping as psychosocial correlates of happiness in people with spinal cord injuries. Rehabilitation Research, Policy, & Education, 27, 186-205.


This product was developed by VCU-RRTC on Employment for People with Physical Disabilities (VCU-RRTC) that is funded by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) grant #90RT503502.  NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents do not necessarily represent the policy of NIDILRR, ACL, HHS, and you should not assume endorsement by the Federal Government. Virginia Commonwealth University, Rehabilitation Research and Training Center is an equal opportunity/affirmative action institution providing access to education and employment without regard to age, race, color, national origin, gender, sexual orientation, veteran’s status, political affiliation, or disability.

The authors for this research brief are Kanako Iwanaga1, Jia-Rung Wu, Xiangli Chen, Fong Chan, and Brian Phillips from the  University of Wisconson-Madison.  Questions on this brief should be directed to Dr. Brian Phillips at Requests for accommodations or questions on the VCU-RRTC should be directed to: Dr. Katherine Inge at or 804-828-5956 Please visit us at: