Resilience, pain, and the brain: Relationships differ by sociodemographics

Abstract

Chronic musculoskeletal (MSK) pain is disabling to individuals and burdensome to society. A relationship between telomere length and resilience was reported in individuals with consideration for chronic pain intensity. While chronic pain associates with brain changes, little is known regarding the neurobiological interface of resilience. In a group of individuals with chronic MSK pain, we examined the relationships between a previously investigated resilience index, clinical pain and functioning measures, and pain-related brain structures, with consideration for sex and ethnicity/race. A cross-sectional analysis of 166 non-Hispanic Black and non-Hispanic White adults, 45-85 years of age with pain ≥ 1 body site (s) over the past 3 months was completed. Measures of clinical pain and functioning, biobehavioral and psychosocial resilience, and structural MRI were completed. Our findings indicate higher levels of resilience associate with lower levels of clinical pain and functional limitations. Significant associations between resilience, ethnicity/race, and/or sex, and pain-related brain gray matter structure were demonstrated in the right amygdaloid complex, bilateral thalamus, and postcentral gyrus. Our findings provide compelling evidence that in order to decipher the neurobiological code of chronic pain and related protective factors, it will be important to improve how chronic pain is phenotyped; to include an equal representation of females in studies including analyses stratifying by sex, and to consider other sociodemographic factors.

Keywords: amygdaloid complex; chronic musculoskeletal pain; pain-related brain structure; resilience; sociodemographic factors.

FIGURE 1

Violin plots distributions of GCPS characteristic pain intensity and GCPS disability scores in individuals with knee pain. The distribution indicates data from individuals who screened positive for knee pain, n = 135

FIGURE 2

Sociodemographic group relationships between resilience and cortical thickness. X axes are unstandardized residuals of resilience with age, site, education, and pain sites regressed out. Y axes are scaled the same to allow for direct thickness comparisons between regions. Circles and solid lines are NHB, triangles and dashed lines are NHW. Postcentral gyrus (in red) has significant Resilience*Ethnicity/Race and Resilience*Ethnicity/Race*Sex interactions (p values < 0.05). The other regions (in blue) did not show significant associations with resilience or resilience interactions (see Table 6)

FIGURE 3

Sociodemographic group relationships between resilience and subcortical volume. X axes are unstandardized residuals of resilience with age, site, education, and pain sites. Circles and solid lines are NHB, triangles and dashed lines are NHW. Refer to Table 5 for a summary of which interactions are significant. Also refer to Figure 4 for two-way interaction graphs

FIGURE 4

Relationships between resilience and stratified sociodemographic variables. X axes are unstandardized residuals of resilience with age, site, education, and pain sites with ethnicity/race and sex as appropriate. Y axes are subcortical volumes adjusted for total intracranial head size

FIGURE 5

Resilience and brain patterns by sociodemographic groups. NHBF, non-Hispanic Black female; NHBM, non-Hispanic Black male; NHWF, non-Hispanic White female; NHWM, non-Hispanic White male. Five cortical and two subcortical areas were investigated: ACC, DLPFC, insula, medial orbitofrontal, postcentral gyrus, amygdala, and thalamus. Areas in dark gray have correlation p values > 0.20, yellow indicates 0.10 > p > 0.05, orange p < 0.05, red p < 0.01. Figure generated using BrainPainter (Marinescu et al., 2019)

FIGURE 6

Relationship between resilience index and a ratio measure between the right and left amygdala. The resilience residual on the X axis controls for age, study site, sex, pain sites, education, and ethnicity/race. The Y axis is the ratio of right:left amygdala volume. This relationship is significant (p = 0.023). The lines represent a linear least squares fit with 95% confidence intervals