Exploring the properties of the Intersectional Discrimination Index - Major in Canadian Veterans with chronic pain
David M Walton1, Pavlos Bobos1, Joy C MacDermid1
1School of Physical Therapy, Western University, London, Ontario, Canada.
Introduction:
Social determinants of pain have been difficult to study because few measurement scales exist. The Intersectional Discrimination Index - Major (InDI-M) is a new, 13-item scale with potential for use in pain research, though little is known about its utility across different populations. This study evaluates the measurement properties of the InDI-M among Canadian military Veterans with chronic pain.
Methods:
Data were collected through an online survey that included the InDI-M and questions related to pain, depression, anxiety, and intersectional identities.
Results:
Factor analysis converged on a 10-item, two-factor structure for the InDI-M. The factors were termed Systemic Inequity (four items; α = 0.68) and Interpersonal Violence (six items; α = 0.78). The pattern of concurrent associations with external criteria revealed meaningful effects of presence of mental health disorder (Interpersonal Violence subscale scores higher among those with depression [6.3/12] or anxiety [6.3/12] than among those without [5.0/12 and 5.1/12, respectively; p < 0.05) but only one significant association with a pain metric (Systemic Inequity with pain interference; r = 0.11, p < 0.05). The Interpersonal Violence subscale showed stronger properties than the Systemic Inequity subscale. The sample was predominantly white and male, reducing response distribution.
Discussion:
The InDI-M appears to be more useful for capturing experiences of interpersonal violence among military Veterans and less so for inequity and marginalization, and it may hold value for pain research. It may capture intersectional discrimination or negative experiences during military service among this population. Suggestions for future research directions are provided.
