Summary: People with chronic pain in multiple parts of the body have a higher risk of developing dementia and accelerated cognitive decline.
Source: Chinese Academy of Science
A research team led by Dr. TU Yiheng from the Institute of Psychology of the Chinese Academy of Sciences has found that people with chronic pain in multiple parts of the body had a higher risk of dementia and experienced broader and faster cognitive decline, including memory, executive function, learning, and attention.
The study was published online in PNAS on Feb. 20.
Multisite chronic pain, where pain is experienced in multiple anatomical locations, affects almost half of chronic pain patients and has been found to place a greater burden on patients’ overall health. However, it has not been clear whether people with multisite chronic pain suffered from aggravated neurocognitive abnormalities.
In this study, after analyzing the records of 354,943 people in the UK Biobank cohort, the researchers found that the risk of neurocognitive abnormality increased with each additional pain site and was mediated by atrophy in the hippocampus, the part of the brain responsible for memory.
Since hippocampal volume decreases with age, the researchers equated the magnitude of the effect of hippocampal atrophy in patients with multisite chronic pain to the effect of aging in healthy people with an average age of 60.
“Multisite chronic pain may lead to up to eight years of accelerated hippocampal aging, an effect that may underlie a series of cognitive burdens,” said Dr. TU, corresponding author of the study.
The study provides a quantitative understanding of the impact of chronic pain on cognitive function and the risk of dementia, laying an important foundation for future research into the relationship between chronic pain and cognitive impairment.
It also highlights the excessive burden of multisite chronic pain on patients’ cognition and the brain, and the need to address the overlapping nature of pain conditions in both basic research and clinical studies.
Funding: This study was supported by the STI2030-Major Projects Program, the National Natural Science Foundation of China, and the Scientific Foundation of the Institute of Psychology of CAS, among other sources.
Elevated dementia risk, cognitive decline, and hippocampal atrophy in multisite chronic pain
Numerous studies have investigated the impacts of common types of chronic pain (CP) on patients’ cognitive function and observed that CP was associated with later dementia. More recently, there is a growing recognition that CP conditions frequently coexist at multiple body sites and may bring more burdens on patients’ overall health.
However, whether and how multisite CP (MCP) contributes to an increased risk of dementia, compared to single-site CP (SCP) and pain-free (PF), is largely unclear.
In the current study, utilizing the UK Biobank cohort, we first investigated dementia risk in individuals (n = 354,943) with different numbers of coexisting CP sites using Cox proportional hazards regression models. We then applied generalized additive models to investigate whether MCP leads to excessive deterioration of participants’ (n = 19,116) cognition and brain structure.
We found that individuals with MCP were associated with significantly higher dementia risk, broader and faster cognitive impairment, and greater hippocampal atrophy than both PF individuals and those with SCP.
Moreover, the detrimental effects of MCP on dementia risk and hippocampal volume aggravated along with the number of coexisting CP sites. Mediation analyses further revealed that the decline of fluid intelligence in MCP individuals was partially mediated by hippocampal atrophy.
Our results suggested that cognitive decline and hippocampal atrophy interact biologically and may underlie the increased risk of dementia associated with MCP.