Pain trends and pain growth disparities, 2009-2021

Unveiling the link: exploring muscle oxygen saturation in fibromyalgia and its implications for symptomatology and therapeutic strategies

Fibromyalgia, characterized as a complex chronic pain syndrome, presents with symptoms of pervasive musculoskeletal pain, significant fatigue, and pronounced sensitivity at specific anatomical sites. Despite extensive research efforts, the origins of fibromyalgia remain enigmatic. This narrative review explores the intricate relationship between muscle oxygen saturation and fibromyalgia, positing that disruptions in the oxygenation processes within muscle tissues markedly influence the symptom profile of this disorder. Muscle oxygen saturation, crucial for muscle function, has been meticulously investigated in fibromyalgia patients through non-invasive techniques such as near-infrared spectroscopy and magnetic resonance imaging. The body of evidence consistently indicates substantial alterations in oxygen utilization within muscle fibers, manifesting as reduced efficiency in oxygen uptake during both rest and physical activity. These anomalies play a significant role in fibromyalgia's symptomatology, especially in terms of chronic pain and severe fatigue, potentially creating conditions that heighten pain sensitivity and accumulate metabolic byproducts. Hypothesized mechanisms for these findings encompass dysfunctions in microcirculation, mitochondrial irregularities, and autonomic nervous system disturbances, all meriting further research. Understanding the dynamics of muscle oxygen saturation in fibromyalgia is of paramount clinical importance, offering the potential for tailored therapeutic approaches to alleviate symptoms and improve the quality of life for sufferers. This investigation not only opens new avenues for innovative research but also fosters hope for more effective treatment strategies and improved outcomes for individuals with fibromyalgia.

Analgesic effect of Botulinum toxin in neuropathic pain is sodium channel independent

Botulinum neurotoxin type A BoNT/A is used off-label as a third line therapy for neuropathic pain. However, the mechanism of action remains unclear. In recent years, the role of voltage-gated sodium channels (Nav) in neuropathic pain became evident and it was suggested that block of sodium channels by BoNT/A would contribute to its analgesic effect. We assessed sodium channel function in the presence of BoNT/A in heterologously expressed Nav1.7, Nav1.3, and the neuronal cell line ND7/23 by high throughput automated and manual patch-clamp. We used both the full protein and the isolated catalytic light chain LC/A for acute or long-term extracellular or intracellular exposure. To assess the toxin's effect in a human cellular system, we differentiated induced pluripotent stem cells (iPSC) into sensory neurons from a healthy control and a patient suffering from a hereditary neuropathic pain syndrome (inherited erythromelalgia) carrying the Nav1.7/p.Q875E-mutation and carried out multielectrode-array measurements. Both BoNT/A and the isolated catalytic light chain LC/A showed limited effects in heterologous expression systems and the neuronal cell line ND7/23. Spontaneous activity in iPSC derived sensory neurons remained unaltered upon BoNT/A exposure both in neurons from the healthy control and the mutation carrying patient. BoNT/A may not specifically be beneficial in pain syndromes linked to sodium channel variants. The favorable effects of BoNT/A in neuropathic pain are likely based on mechanisms other than sodium channel blockage and new approaches to understand BoNT/A's therapeutic effects are necessary.

Global pain levels before and during the COVID-19 pandemic

Physical pain has trended upward globally over the last decade. Here, we explore whether the COVID-19 pandemic modified this alarming trend. We used data from 146 countries worldwide (510,247 respondents) to examine whether pain levels changed during the COVID-19 pandemic. Adjusted regressions across countries revealed that 33.3% of people were in pain in 2019, 32.8% in 2020, 32.5% in 2021, and 34.1% in 2022. The change in pain from 2019 to each of the pandemic years was not statistically significant. This suggests that, on average, there was no significant change in pain during the pandemic. However, from 2019 to 2020 there was a significant decline in pain among individuals over 55 years of age, those who were widowed, and those without children in the household. On a global scale, the COVID-19 pandemic was not associated with a significant change in pain levels. The concerning pre-pandemic elevation in global pain continued during this challenging period.

Prevalence of Pain and Its Relationship with Age and Sex among Patients in Saudi Arabia

BACKGROUND

Studies investigating the prevalence of patients with pain referred for physical therapy in Saudi Arabia are scarce. This study aimed to estimate the period prevalence of pain that led to referrals for physical therapy and to evaluate the association between pain and patient age and sex.

METHODS

This retrospective study used data from the electronic health record system of a hospital for adult patients referred for physical therapy.

RESULTS

In total, 7426 (26.0%) patients (mean (±SD) age, 51.4 ± 15.0 years) experienced pain, the majority of whom were female (65.8%). The back (30.7%) was the most commonly reported pain region, followed by the neck (13.2%), shoulders (12.1%), and knees (11.8%). The referring physician(s) identified pain in a specific body region in 5894 of the 7426 (79.4%) patients. A moderate correlation was found between sex and pain region (Cramer's V = 0.151, p < 0.001) and between age group and pain region (Cramer's V = 0.10, p < 0.001).

CONCLUSIONS

Pain was prevalent among adult patients referred for physical therapy and was moderately associated with sex and age. Further research examining the prevalence of pain and its risk factors in a larger, representative sample of the population is warranted.

Income is more protective against pain in more equal countries

It is empirically well-established that the rich suffer less pain on average than the poor. However, much less is known about the factors that moderate the size of the income gradient of pain. Using data from over 1 million adults from 127 countries worldwide, this article conducts a systematic test on whether income inequality moderates the pain gap between the rich and the poor. While pain is negatively associated with income in all but one country, there is strong evidence to suggest that an increase in income is much more protective against pain in countries where the income distribution is relatively more equal. The results are robust to using different measures of income inequality, removing outliers, and accounting for country and year fixed effects. We explain our results through the lens of income rank effects on health outcomes. Overall, our findings suggest that pain-reducing policies through income redistribution may need to take income inequality into consideration when evaluating their effectiveness.

The effect of adverse employment circumstances on physical pain: Evidence from Australian panel data

Physical pain is a common health problem with great public health implications. Yet evidence on whether adverse employment circumstances shape physical pain is limited. Using longitudinal data from 20 waves (2001-2020) from the Household, Income and Labour Dynamics of Australia Survey (HILDA; N = 23,748), a lagged design, Ordinary Least Squares (OLS) regressions as well as multilevel mixed effect linear regressions, we investigated the association between past accumulated unemployment and recent employment circumstances with physical pain. We found that adults who spent more years unemployed and looking for work subsequently reported greater physical pain (b = 0.034, 95% CI = 0.023, 0.044) and pain interference (b = 0.031, 95% CI = 0.022, 0.038) than those who spent fewer years unemployed. We also found that those experiencing overemployment (working full-time while wanting to work fewer hours) and underemployment (working part-time while wanting to work more hours) reported greater subsequent physical pain (overemployment: b = 0.024, 95% CI = 0.009, 0.039; underemployment: b = 0.036, 95% CI = 0.014, 0.057) and pain interference (overemployment: b = 0.017, 95% CI = 0.005, 0.028; underemployment: b = 0.026, 95% CI = 0.009, 0.043) than those content with their working hours. These results held after controlling for socio-demographic characteristics, occupation, and other health-related factors. These findings are consistent with recent work that suggested that psychological distress can influence physical pain. Understanding how adverse employment circumstances impact physical pain is crucial to the design of health promotion policies.