Greater socioenvironmental risk factors and higher chronic pain stage are associated with thinner bilateral temporal lobes.

INTRODUCTION: Previous research indicates ethnic/race group differences in pain and neurodegenerative diseases. Accounting for socioenvironmental factors reduces ethnic/race group differences in clinical and experimental pain. In the current study sample, we previously reported that in individuals with knee pain, ethnic/race group differences were observed in bilateral temporal lobe thickness, areas of the brain associated with risk for Alzheimer's disease, and related dementias. The purpose of the study was to determine if socioenvironmental factors reduce or account for previously observed ethnic/race group differences and explore if a combined effect of socioenvironmental risk and chronic pain severity on temporal lobe cortices is evident. METHODS: Consistent with the prior study, the sample was comprised of 147 adults (95 women, 52 men), 45-85 years of age, who self-identified as non-Hispanic Black (n = 72) and non-Hispanic White (n = 75), with knee pain with/at risk for osteoarthritis. Measures included demographics, health history, pain questionnaires, cognitive screening, body mass index, individual- and community-level socioenvironmental factors (education, income, household size, marital and insurance status, and area deprivation index), and brain imaging. We computed a summative socioenvironmental risk index. RESULTS: Regression analyses showed that with the inclusion of socioenvironmental factors, the model was significant (p < .001), and sociodemographic (ethnic/race) group differences were not significant (p = .118). Additionally, findings revealed an additive stress load pattern indicating thinner temporal lobe cortices with greater socioenvironmental risk and chronic pain severity (p = .048). IMPLICATIONS: Although individual socioenvironmental factors were not independent predictors, when collectively combined in models, ethnic/race group differences in bilateral temporal lobe structures were not replicated. Further, combined socioenvironmental risk factors and higher chronic pain severity were associated with thinner bilateral temporal lobes.

Racial Differences in 25-Hydroxy Vitamin D and Self-Reported Pain Severity in a Sample of Individuals Living with Non-Specific Chronic Low Back Pain.

Introduction: Considerable evidence suggests that there are significant ethnic/racial differences in the experience of pain among individuals suffering from chronic musculoskeletal conditions. Additionally, low levels of vitamin D have been associated with pain severity. Further, vitamin D deficiency is more prevalent in Non-Hispanic Black (NHB) individuals compared to Non-Hispanic Whites (NHW). Objective: The aim of this study was to investigate the associations among race, pain severity, and serum levels of vitamin D in a sample of patients with chronic low back pain (cLBP). Methods: All study participants (n = 155) self-identified their race/ethnicity as either NHB or NHW. Blood samples were collected to assess circulating levels of serum 25- hydroxy vitamin D. Vitamin D levels were categorized as optimal (≥20 ng/mL), insufficient (12-19 ng/mL) or deficient (<12 ng/mL). Participants then self-reported their pain severity using the Brief Pain Inventory - Short Form. Results: Results showed that a greater proportion of NHB versus NHW participants were categorized as Vitamin D deficient (χ 2 (2, N = 155) = 16.79, p < 0.001). An analysis of covariance (ANCOVA) revealed that NHBs reported significantly greater pain severity relative to NHWs (F(1150) = 6.45) p = 0.012. Further, self-reported pain severity significantly differed according to Vitamin D clinical categories (F(2150) = 4.19, p = 0.013). Participants with deficient vitamin D reported significantly greater pain severity in comparison to participants with optimal vitamin D (F(1101) = 7.28, p = 0.008). Conclusion: The findings suggest that Vitamin D deficiency may be linked to greater pain severity in a sample of individuals with cLBP, especially for those who identify as NHB.

The Area Deprivation Index Corresponds Effectively With Other Measures of Objective Socioeconomic Status in Adults With Chronic Low Back Pain.

Background and Purpose: How the Area Deprivation Index (ADI) performs compared to other measures of socioeconomic status (SES) is unknown. The study purpose is to compare the ADI and other measures of SES in their ability to predict pain severity/interference. Methods: Four measures of SES were compared-ADI, income, education, and subjective social status (SSS). Results: Pain severity/interference correlated positively with ADI (r = .396/r = .33), and negatively with income (r = -.507/r = -.428) and education (r = -.271/r = -.102). Criterion scores of the pain severity model suggest income performs best (AIC = 428.29/BIC = 436.22), followed by ADI (AIC = 437.24/BIC = 445.17), with education performing least well (AIC = 446.35/BIC = 454.29). Similar results were seen for the pain interference model. Conclusions: Neighborhood-level factors warrant consideration along with individual-level factors when attempting to understand the impact of SES on chronic low back pain.

Sleep and neighborhood socioeconomic status: a micro longitudinal study of chronic low-back pain and pain-free individuals.

Individuals with chronic low back pain (cLBP) frequently report sleep disturbances. Living in a neighborhood characterized by low-socioeconomic status (SES) is associated with a variety of negative health outcomes, including poor sleep. Whether low-neighborhood SES exacerbates sleep disturbances of people with cLBP, relative to pain-free individuals, has not previously been observed. This study compared associations between neighborhood-level SES, pain-status (cLBP vs. pain-free), and daily sleep metrics in 117 adults (cLBP = 82, pain-free = 35). Neighborhood-level SES was gathered from Neighborhood Atlas, which provides a composite measurement of overall neighborhood deprivation (e.g. area deprivation index). Individuals completed home sleep monitoring for 7-consecutive days/nights. Neighborhood SES and pain-status were tested as predictors of actigraphic sleep variables (e.g., sleep efficiency). Analyses revealed neighborhood-level SES and neighborhood-level SES*pain-status interaction significantly impacted objective sleep quality. These findings provide initial support for the negative impact of low neighborhood-level SES and chronic pain on sleep quality.

Temporal summation of mechanical pain prospectively predicts movement-evoked pain severity in adults with chronic low back pain.

BACKGROUND: Biopsychosocial factors above and beyond pathoanatomical changes likely contribute to the severity of chronic low back pain. A pro-nociceptive endogenous pain modulatory balance (↓inhibition and ↑facilitation) may be an important contributor to chronic low back pain severity and physical function; however, additional research is needed to address this possibility. The objective of this study was to determine whether quantitative sensory tests of endogenous pain inhibition and facilitation prospectively predict movement-evoked pain and cLBP severity self-reported on a validated questionnaire. METHODS: One hundred thirty-four individuals with chronic low back pain were enrolled in this two-session study. During the first study session, temporal summation of mechanical pain and conditioned pain modulation were assessed at the lumbar spine to determine endogenous pain facilitation and inhibition, respectively. One week later, participants returned for a second study session whereby they reported their pain severity and pain interference using the Brief Pain Inventory-Short Form. Movement-evoked pain and physical function capacity were assessed upon completion of the balance, walking, and transition from sit to stand tests of the Short Physical Performance Battery. RESULTS: Temporal summation of mechanical pain, but not conditioned pain modulation, significantly and prospectively predicted greater movement-evoked pain and poorer physical function on the Short Physical Performance Battery. Neither temporal summation nor conditioned pain modulation were significantly related to self-reported pain severity or pain interference on the Brief Pain Inventory-Short Form. CONCLUSIONS: Findings suggest that a pro-nociceptive pain modulatory balance characterized by enhanced pain facilitation may be an important driver of movement-evoked pain severity and poor physical function in individuals with chronic low back pain.

Pain-Related Injustice Appraisals in Youth with Sickle Cell Disease: A Preliminary Investigation.

OBJECTIVES: Sickle cell disease (SCD) is a genetic disorder that affects approximately 100,000 Americans, the majority of whom are African American. SCD-related pain often has deleterious effects on functioning and quality of life. The inherited nature of SCD, SCD-related stigma, and serious physical and functional impact of SCD-related pain create a situation ripe for individuals to appraise their SCD-related pain as unfair or unjust. The aim of this preliminary investigation is to explore the extent to which pediatric patients with SCD appraise their pain as unjust and how these appraisals relate to functioning. METHODS: Participants were youth with SCD (N = 30, mean age = 11.3, 57% boys) who attended a hematology clinic visit. Patients were invited to complete paper-based questionnaires assessing pain-related injustice appraisals, pain catastrophizing, pain and hurt, functional disability, depression, anxiety, and peer relationships. RESULTS: Results of hierarchical regressions indicate that pain-related injustice significantly predicted functional disability, depression, and anxiety after controlling for patient pain and catastrophizing. CONCLUSIONS: These findings suggest that pain-related injustice appraisals are an important contributor to the pain experience of youth with SCD. Early identification and remediation of pain-related injustice appraisals could have long-term functional benefits for youth with SCD.

Sociodemographic Differences in Pain Medication Usage and Healthcare Provider Utilization Among Adults With Chronic Low Back Pain.

Chronic low back pain (cLBP) is the most common reason for individual suffering and health care utilization in adults. Ample evidence suggests sociodemographic variables and socioeconomic status (SES) influence pain. However, a framework informing associations on race, SES, and the utilization of pharmacologic therapies and provider type are limited-particularly in cLBP. Thus, this study examined the extent to which sociodemographic (i.e., age, race, and gender) and socioeconomic factors (i.e., national area deprivation index, NADI) influence pain treatment (i.e., NSAIDs, opioids, antidepressants, and non-NSAIDs) and provider utilization for cLBP (i.e., no provider care, primary care, or tertiary care). Eligible participants with cLBP completed a series of questionnaires. Of the 174 participants, 58% were women, 59% were non-Hispanic Black (NHB), and the mean age was 46.10 (SD 13.58). Based on NADI distributions by race, NHB participants lived in more socioeconomically disadvantaged neighborhoods (p < 0.001) than non-Hispanic White (NHW) adults. Results suggested that the use of one or more pharmacologic therapies was associated with race (p = 0.021). Specifically, NHW adults were two times more likely to take one or more pharmacologic therapies than NHBs (p = 0.009). NHWs were also more likely to use NSAIDs (p = 0.041) and antidepressants (p < 0.001) than NHBs. Furthermore, provider utilization was significantly associated with gender (p = 0.037) and age (p = 0.018); which suggests older women were more likely to use primary or tertiary care. Findings from this study expand on the existing literature as it relates to associations between disparities in access to healthcare providers and access to medications. Future research should seek to understand differences in age and utilization of primary or tertiary care providers and continue to examine the influence of sociodemographic and SES factors to cLBP and compare with other types of chronic pain.

Race, Social Status, and Depressive Symptoms: A Moderated Mediation Analysis of Chronic Low Back Pain Interference and Severity.

BACKGROUND: Chronic low back pain (cLBP) is the leading cause of disability, with a significant societal cost. It disproportionately affects non-Hispanic blacks and individuals of lower socioeconomic status. The biopsychosocial framework has been used to study and manage cLBP, yet disparities persist. OBJECTIVE: The objective of this study was to assess whether self-identified race moderated the relationship between perceived social status and cLBP outcomes (pain interference and pain severity) and investigate whether race moderated the indirect relationship between perceived social status and pain outcomes via depressive symptoms. METHODS: Fifty-seven blacks and 48 whites with cLBP were recruited as part of a large ongoing study. Depressive symptoms, objective and subjective measures of socioeconomic status, and pain outcomes were measured. Hayes' moderated mediation model was used to estimate conditional direct and indirect relationship between these variables. RESULT: On average black participants reported significantly more pain interference (4.12 [SD=2.65] vs. 2.95 [SD=2.13]) and severity (5.57 [SD=2.27] vs. 3.99 [SD=1.99]) than white participants, (P<0.05). Race moderated the association between perceived social status and pain interference: higher social status decreases pain interference for white participants, but that trend was not observed in black participants. Moreover, race moderated association of perceived social status with depressive symptoms (P<0.001); which mediates the effects of perceived social status on pain outcomes. CONCLUSION: Higher perceived social status is associated with less severe depressive symptoms, which in turn is associated with less pain severity and less pain interference for whites but not for blacks with cLBP.

Perceived Injustice Helps Explain the Association Between Chronic Pain Stigma and Movement-Evoked Pain in Adults with Nonspecific Chronic Low Back Pain.

OBJECTIVE: For most patients with chronic low back pain (cLBP), the cause is "nonspecific," meaning there is no clear association between pain and identifiable pathology of the spine or associated tissues. Laypersons and providers alike are less inclined to help, feel less sympathy, dislike patients more, suspect deception, and attribute lower pain severity to patients whose pain does not have an objective basis in tissue pathology. Because of these stigmatizing responses from others, patients with cLBP may feel that their pain is particularly unjust and unfair. These pain-related injustice perceptions may subsequently contribute to greater cLBP severity. The purpose of this study was to examine whether perceived injustice helps explain the relationship between chronic pain stigma and movement-evoked pain severity among individuals with cLBP. METHODS: Participants included 105 patients with cLBP who completed questionnaires assessing chronic pain stigma and pain-related injustice perception, as well as a short physical performance battery for the assessment of movement-evoked pain and physical function. RESULTS: Findings revealed that perceived injustice significantly mediated the association between chronic pain stigma and cLBP severity (indirect effect = 6.64, 95% confidence interval [CI] = 2.041 to 14.913) and physical function (indirect effect = -0.401, 95% CI = -1.029 to -0.052). Greater chronic pain stigma was associated with greater perceived injustice (P = 0.001), which in turn was associated with greater movement-evoked pain severity (P = 0.003). CONCLUSIONS: These results suggest that perceived injustice may be a means through which chronic pain stigma impacts nonspecific cLBP severity and physical function.

Step-by-step variability of swing phase trajectory area during steady state walking at a range of speeds.

BACKGROUND: Step kinematic variability has been characterized during gait using spatial and temporal kinematic characteristics. However, people can adopt different trajectory paths both between individuals and even within individuals at different speeds. Single point measures such as minimum toe clearance (MTC) and step length (SL) do not necessarily account for the multiple paths that the foot may take during the swing phase to reach the same foot fall endpoint. The purpose of this study was to test a step-by-step foot trajectory area (SBS-FTA) variability measure that is able to characterize sagittal plane foot trajectories of varying areas, and compare this measure against MTC and SL variability at different speeds. We hypothesize that the SBS-FTA variability would demonstrate increased variability with speed. Second, we hypothesize that SBS-FTA would have a stronger curvilinear fit compared with the CV and SD of SL and MTC. Third, we hypothesize SBS-FTA would be more responsive to change in the foot trajectory at a given speed compared to SL and MTC. Fourth, SBS-FTA variability would not strongly co-vary with SL and MTC variability measures since it represents a different construct related to foot trajectory area variability. METHODS: We studied 15 nonimpaired individuals during walking at progressively faster speeds. We calculated SL, MTC, and SBS-FTA area. RESULTS: SBS-FTA variability increased with speed, had a stronger curvilinear fit compared with the CV and SD of SL and MTC, was more responsive at a given speed, and did not strongly co-vary with SL and MTC variability measures. CONCLUSION: SBS foot trajectory area variability was sensitive to change with faster speeds, captured a relationship that the majority of the other measures did not demonstrate, and did not co-vary strongly with other measures that are also components of the trajectory.