Background: Cognitive decline and dementia represent a major health and social care challenge in the twenty-first century as a leading cause of morbidity and mortality affecting over 55 million people globally. Back pain (BP) and neck pain (NP), often referred to collectively as spinal pain, contribute to additional health challenges in the elderly and is acknowledged as the primary cause of years lived with disability often co-existing with cognitive decline and neurodegeneration. Despite their co-existence, our current understanding of the mechanisms that potentially link BP and NP to accelerated cognitive decline remains uncertain.
Hypothesis: We hypothesise that elderly adults reporting spinal pain would exhibit lower cognition scores, and that this would be more pronounced in females, given their established vulnerability to later-life neurodegeneration.
Methods: To investigate the potential relationships between BP/NP and cognitive decline, we conducted a retrospective cross-sectional analysis of the Longitudinal Study of Aging Danish Twins Database as part of the Danish Twins Registry adjusting for age, sex, educational and socioeconomic status. Ethical approval was granted by the Faculty of Life Sciences and Education Ethics Committee at the University of South Wales (#19DB0501LR).
Results: A total of 4,731 adults (2,788 females/1,943 males) aged 78±6 (SD) years were included in the analysis. We observed a one-month prevalence of 25% with BP, 21% with NP and 11% for combined BP/NP. While there were no differences in cognition scores for male and females reporting combined BP/NP, compared to those without combined BP/NP (34.38 points; 95% CI=31.88, 36.88 vs 35.72 points; 95% CI=35.19, 36.26; P=0.180; and 35.72 points; 95% CI=35.19, 36.26 vs 35.85 points; 95% CI=35.39, 36.31; P=0.327, for male and females respectively), an adjusted analysis revealed that males with combined BP/NP presented with lower cognitive scores compared to males without combined BP/ NP (79.48 points; 95% CI=70.31, 88.66; P=0.043 vs 81.26 points; 95% CI=73.80, 88.72, respectively).
Conclusions: In the current study, males reporting combined BP and NP exhibited lower composite cognitive scores compared to males without combined BP and NP when adjusting for age, sex, educational and socioeconomic status. The fact that male twins reporting both BP and NP presented with lower cognitive scores may be due to males carrying more cardio-cerebrovascular risk factors (i.e., greater vascular disease burden) than females. Accordingly, an elevation in cardiometabolic risk factors and the pattern of combined BP and NP symptomatology may have the potential to increase systemic oxidative-inflammatory-nitrosative stress (OXINOS). Given this was only observed in males, these findings suggest a ‘sex-specific susceptibility’ to cognitive decline and supports the notion that combined BP and NP may be considered as an additional cardio-cerebrovascular risk factor for later life neurodegeneration warranting further investigation.