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. We aimed 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. We estimated 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 = -0.474; P = 0.005), a less agreeable (r = -0.439; P = 0.020), and less emotionally stable personality (r = -0.387; 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.