Is cognitive decline related to spinal pain?

This week’s review features a commentary from my friend and colleague, and lead author of this paper, Dr. David Byfield (included below)…

Cognitive decline and dementia are of major concern internationally and a leading cause of global morbidity and mortality. Over 55 million people are affected by dementia worldwide and this is expected to increase to 152 million by 2050. The most common type of dementia is Alzheimer’s disease, which mostly affects females (2/3 of Alzheimer’s patients are females).

Back pain (BP) and neck pain (NP), commonly referred to as spinal pain, frequently co-exist with cognitive decline and neurodegeneration, leading to reduced functional capacity and lower quality of life. Chronic spinal pain is more disabling in older adults and may lead to decreased mobility, fewer social interactions, and a sedentary lifestyle which may have a negative impact on cognitive function. Furthermore, both spinal pain and dementia have been shown to be much more prevalent among females globally. Nonetheless, although various theories exist, the underlying physiological mechanisms connecting spinal pain and accelerated cognitive decline is uncertain.

The aim of this current study was to determine the potential relationship(s) between spinal pain and cognitive decline, including its variation by age and sex, which has not been previously investigated. The authors hypothesized that elderly adults reporting spinal pain would exhibit lower cognition scores, and that this would be more pronounced in females, given their vulnerability to later-life neurodegeneration.

Commentary from Study Lead Author, Dr. David Byfield:

In this paper, we aimed to determine the potential relationship(s) between spinal pain (defined as back and neck pain) and cognitive decline including its modulation by age and sex in elderly twins, which we feel had not been previously investigated.  This was a hypothesis-generating study which included a retrospective analysis of the Longitudinal Study of Ageing Danish Twins part of the Danish Twins Registry.  The data suggested that male twins over 70 + years who reported combined back and neck pain had significantly lower cognitive scores than males that reported no pain.  This wasn’t the case for female twins in the analysis, with no change in cognition with or without spinal pain, which contradicts the higher spinal pain and cognitive decline prevalence reported in females across the globe.  Our findings were interpreted with some caution due to the nature of the data and other limitations fully outlined in the publication. 

While speculative at this stage, we hypothesised two potential mechanisms that may explain the observed relationship between spinal pain and cognitive decline. First, a systemic/local elevation in oxidative-inflammatory-nitrosative stress (OXINOS), either as a cause or consequence of spinal pain, may prove the unifying molecular mechanism underlying vascular endothelial dysfunction and structural damage to the neurovascular unit that collectively precede cognitive decline and neurodegeneration. Furthermore, OXINOS has the potential to interfere with immunological processes of the brain and accelerate cognitive decline subsequent to microglia activation. In further support, bio-inflammatory markers, for example, C-reactive protein, tumour necrosis factor-a and interleukin-6 have been shown to be consistently elevated in patients with spinal pain.Second, the musculoskeletal disability and exacerbation of related pain may further promote physical inactivity resulting in a more sedentary existence. This can further compound OXINOS and accelerate cognitive decline subsequent to cerebral hypoperfusion and corresponding reduction in cerebral substrate (oxygen/glucose) delivery. Clearly, further research is encouraged to explore the mechanistic bases underlying the observed relationships reported in this hypothesis-generating study.

Professor David Byfield is a part time PhD student aligned to the Neurovascular Research Laboratory at the University of South Wales under the direction of Prof Damian Bailey.  The Neurovascular lab is interested in all things cerebrovascular measuring the impact on the brain and cognition.  The lab has a global reputation as a centre of research excellence investigating how the brain copes in extreme physiological conditions for example, high altitude hypoxia, repetitive brain injury (concussion) and how the brain responds to high intensity interval training and cognition.  His work is specifically exploring the impact of chronic spinal pain, physical inactivity and the link to accelerated cognitive decline.  Despite their co-existence, the understanding of the underlying physiological mechanisms that could potentially link spinal pain and accelerated cognitive decline remains unclear, however, it is important for clinicians to realize the impact of prolonged physical inactivity on overall health particularly on the brain and the risk of developing cognitive decline and other neurodegenerative disease.

This week’s Research Review: “Cognition is Selectively Impaired in Males with Spinal Pain“

This paper was published in Experimental Physiology (2024)

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