Association between chronic low back pain and regional brain atrophy in a Japanese older population: the Hisayama Study

Chronic low back pain (CLBP) is the leading cause of years lived with disability. Recently, it has been reported that CLBP is associated with alterations in the central nervous system. The present study aimed to investigate the association between CLBP and regional brain atrophy in an older Japanese population. A total of 1106 community-dwelling participants aged ≥65 years underwent brain magnetic resonance imaging scans and a health examination in 2017 to 2018. We used the FreeSurfer software for the analysis of brain magnetic resonance imaging. Chronic pain was defined as subjective pain for ≥3 months. Participants were divided into 3 groups according to the presence or absence of chronic pain and the body part that mainly suffered from pain: a "no chronic pain (NCP)" group (n = 541), "CLBP" group (n = 189), and "chronic pain in body parts other than the lower back (OCP)" group (n = 376). The brain volumes of the ventrolateral and dorsolateral prefrontal cortex, the posterior cingulate gyrus, and the amygdala were significantly lower in the CLBP group than in the NCP group after adjustment for sociodemographic, physical, and lifestyle factors and depressive symptoms. In addition, the left superior frontal gyrus was identified as a significant cluster by the Query, Design, Estimate, Contrast interface. There were no significant differences in the brain volumes of pain-related regions between the NCP and the OCP groups. The present study suggests that CLBP is associated with lower brain volumes of pain-related regions in a general older population of Japanese.