Chronic pain is associated with a brain aging biomarker in community-dwelling older adults

Chronic pain is associated with brain atrophy with limited evidence on its impact in the older adult's brain. Weaimed to determine the associations between chronic pain and a brain aging biomarker in persons aged 60 to 83 years old. Participants of the Neuromodulatory Examination of Pain and Mobility Across the Lifespan (NEPAL) study (N = 47) completed demographic, psychological, and pain assessments followed by a quantitative sensory testing battery and a T1-weighted magnetic resonance imaging. Weestimated a brain-predicted age difference (brain-PAD) that has been previously reported to predict overall mortality risk (brain-PAD, calculated as brain-predicted age minus chronological age), using an established machine-learning model. Analyses of covariances and Pearson/Spearman correlations were used to determine associations of brain-PAD with pain, somatosensory function, and psychological function. Individuals with chronic pain (n = 33) had "older" brains for their age compared with those without (n=14; F[1,41] = 4.9; P=0.033). Greater average worst pain intensity was associated with an "older" brain (r=0.464; P=0.011). Among participants with chronic pain, those who reported having pain treatments during the past 3 months had " younger" brains compared with those who did not (F[1,27] = 12.3; P = 0.002). An "older" brain was significantly associated with decreased vibratory (r=0.323; P=0.033) and thermal (r=0.345; P=0.023) detection, deficient endogenous pain inhibition (F[1,25] = 4.6; P = 0.044), lower positive affect (r = 20.474; P = 0.005), a less agreeable (r = 20.439; P = 0.020), and less emotionally stable personality (r = 20.387; P = 0.042). Our findings suggest that chronic pain is associated with added "age-like" brain atrophy in relatively healthy, community-dwelling older individuals, and future studies are needed to determine the directionality of our findings. A brain aging biomarker may help identify people with chronic pain at a greater risk of functional decline and poorer health outcomes.