Objective: Osteoarthritis is the most prominent form of arthritis, affecting approximately 15% of the population in the United States. Knee osteoarthritis (KOA) has become one of the leading causes of disability in older adults. Besides knee replacement, there are no curative treatments for KOA, so persistent pain is commonly treated with opioids, acetaminophen, and nonsteroidal anti-inflammatory drugs. However, these drugs have many unpleasant side effects, so there is a need for alternative forms of pain management. We sought to test the efficacy of a dietary intervention to reduce KOA.Design: A randomized controlled pilot study to test the efficacy of two dietary interventions.Subjects: Adults 65–75 years of age with KOA.Methods: Participants were asked to follow one of two dietary interventions (low-carbohydrate [LCD], low-fat [LFD]) or continue to eat as usual (control [CTRL]) over 12 weeks. Functional pain, self-reported pain, quality of life, and depression were assessed every three weeks. Serum from before and after the diet intervention was analyzed for oxidative stress.Results: Over a period of 12 weeks, the LCD reduced pain intensity and unpleasantness in some functional pain tasks, as well as self-reported pain, compared with the LFD and CTRL. The LCD also significantly reduced oxidative stress and the adipokine leptin compared with the LFD and CTRL. Reduction in oxidative stress was related to reduced functional pain.Conclusions: We present evidence suggesting that oxidative stress may be related to functional pain, and lowering it through our LCD intervention could provide relief from pain and be an opioid alternative.

“Intersectional health-related stigma” (IHRS) refers to stigma that arises at the convergence of multiple health conditions. People living with HIV (PLWH) and chronic pain have two highly stigmatized health conditions, and thus may be at especially high risk for internalizing these stigmas and consequently experiencing depression. This study examined the intersectionality of internalized HIV and chronic pain stigma in relation to depressive symptoms in a sample of PLWH and chronic pain. Sixty participants were recruited from an HIV clinic in the Southeastern United States. Chronic pain was defined as pain that has been present for at least three consecutive months, and that has been an ongoing problem for at least half the days in the past six months. All participants completed the HIV Stigma Mechanisms Scale, Internalized Stigma in Chronic Pain Scale, the Short-Form Brief Pain Inventory, and the Center for Epidemiological Studies – Depression Scale. Clinical data was collected from medical records. An intersectional HIV and chronic pain composite variable was created and participants were categorized as either high (28%), moderate (32%), or low (40%). Results revealed that intersectional HIV and chronic pain stigma was significantly associated with severity of depressive symptoms (p = .023). Pairwise contrasts revealed that participants with high (p = .009) and moderate (p = .033) intersectional stigma reported significantly greater mean depressive symptom severity than those with low intersectional stigma. Participants who reported the highest levels of internalized HIV and chronic pain stigma also reported the greatest severity of depressive symptoms. This suggests that the experience of both HIV and chronic pain stigma (i.e., IHRS) among PLWH and chronic pain may synergistically perpetuate negative mood in a more profound manner than experiencing either one stigma alone.

Background: Sex differences in pain sensitivity have been well documented, such that women often report greater sensitivity than men. However, clinical reports highlighting sex differences often equate gender and sex. This is a particularly critical oversight for those whose gender identity is different than their genetic sex. Methods: This preliminary study sets to analyze differences in pain responses between cisgender and transgender individuals living with HIV and chronic pain. A total of 51 African-American participants (24 cisgender men, 20 cisgender women, 7 transgender women) with similar socioeconomic status were recruited. Genetic sex, gender identity, depression and anxiety, pain severity, pain interference and pain-related stigma were recorded. Participants also completed a quantitative sensory testing battery to assess pain in response to noxious heat and mechanical stimuli. Results: Transgender women and cisgender women demonstrated a greater magnitude of temporal summation for heat pain stimuli or mechanical stimuli compared to cisgender men. Specifically, transgender women reported greater mechanical summation than either cisgender women or cisgender men. Transgender women and cisgender women similarly reported greater chronic pain severity compared to cisgender men. Conclusion: These data support the notion that gender identity may play a more significant role in pain sensation than genetic sex. These results further maintain that not only gender identity and genetic sex are distinct variables but that treatment should be based on identity as opposed to genetic sex.

Background and aims: Obesity is a significant health concern in the Western world and the presence of comorbid conditions suggests an interaction. The overlapping distributions of chronic pain populations and obesity suggests that an interaction may exist. Poor quality diet (high carbohydrates, saturated fats, omega-6 polyunsaturated fatty acids) can lead to increased adiposity which can activate immune cells independent of the activating effect of the diet components themselves. This dual action can contribute to chronic inflammation that may alter susceptibility to chronic pain and prolong recovery from injury. However, traditional examinations of diet focus on high-fat diets that often contain a single source of fat, that is not reflective of an American diet. Thus, we examined the impact of a novel human-relevant (high-carbohydrate) American diet on measures of pain and inflammation in rats, as well as the effect on recovery and immune cell activation. Methods: We developed a novel, human-relevant Standard American Diet (SAD) to better model the kilocalorie levels and nutrient sources in an American population. Male and female rats were fed the SAD over the course of 20 weeks prior to persistent inflammatory pain induction with Complete Freund’s Adjuvant (CFA). Mechanical and thermal sensitivity were measured weekly. Spontaneous pain, open field locomotion and blood glucose levels were measured during diet consumption. Body composition was assessed at 20 weeks. Following full recovery from CFA-induced hypersensitivity, blood was analyzed for inflammatory mediators and spinal cords were immunohistochemically processed for microglial markers. Results: Chronic consumption of the SAD increased fat mass, decreased lean mass and reduce bone mineral density. SAD-fed rats had increased leptin levels and pro-inflammatory cytokines in peripheral blood serum. Following CFA administration, mechanical sensitivity was assessed and recovery was delayed significantly in SAD-fed animals. Sex differences in the impact of the SAD were also observed. The SAD increased body weight and common T-cell related inflammatory mediators in female, but not male, animals. In males, the SAD had a greater effect on bone mineral density and body composition. Long-term consumption of the SAD resulted in elevated microglial staining in the dorsal horn of the spinal cord, but no sex differences were observed. Conclusions: We demonstrate the negative effects of an American diet on physiology, behavior and recovery from injury. SAD consumption elevated pro-inflammatory mediators and increased microglial activation in the spinal cord. While there were sex differences in weight gain and inflammation, both sexes showed prolonged recovery from injury. Implications: These data suggest that poor quality diet may increase susceptibility to chronic pain due to persistent peripheral and central immune system activation. Furthermore, consumption of a diet that is high in carbohydrates and omega-6 polyunsaturated fatty acid is likely to lead to protracted recovery following trauma or surgical procedures. These data suggest that recovery of a number of patients eating a poor quality diet may be expedited with a change in diet to one that is healthier.

Objective: This study evaluated whether food insecurity (US Adult Food Security Survey) was associated with chronic pain (≥ 3 months) and high-impact chronic pain (i.e. pain that limits work and life) among US adults. Design: Cross-sectional analysis. Setting: Nationally representative sample of non-institutionalised adults in the USA. Participants: 79 686 adults from the National Health Interview Survey (2019–2021). Results: Marginal, low and very low food security were associated with increased prevalence odds of chronic pain (OR: 1·58 (95 % CI 1·44, 1·72), 2·28 (95 % CI 2·06, 2·52) and 3·37 (95 % CI 3·01, 3·78), respectively) and high-impact chronic pain (OR: 1·28 (95 % CI 1·14, 1·42), 1·55 (95 % CI 1·37, 1·75) and 1·90 (95 % CI 1·65, 2·18), respectively) in a dose–response fashion (P-trend < 0·0001 for both), adjusted for sociodemographic, socio-economic and clinically relevant factors. Participation in Supplemental Nutrition Assistance Program (SNAP) and age modified the association between food insecurity and chronic pain. Conclusions: These findings illustrate the impact of socio-economic factors on chronic pain and suggest that food insecurity may be a social determinant of chronic pain. Further research is needed to better understand the complex relationship between food insecurity and chronic pain and to identify targets for interventions. Moreover, the consideration of food insecurity in the clinical assessment of pain and pain-related conditions among socio-economically disadvantaged adults may be warranted.