The pace of biological aging significantly mediates the relationship between internalized stigma of chronic pain and chronic low back pain severity among non-hispanic black but not non-hispanic white adults

This study aimed to determine the nature of the relationship between the internalized stigma of chronic pain (ISCP), the pace of biological aging, and racial disparities in nonspecific chronic low back pain (CLBP). We used Dunedin Pace of Aging from the Epigenome (DunedinPACE), Horvath's, Hannum's, and PhenoAge clocks to determine the pace of biological aging in adults, ages 18 to 82 years: 74 no pain, 56 low-impact pain, and 76 high-impact pain. Individuals with high-impact pain reported higher levels of ISCP and DunedinPACE compared to those with low-impact or no pain (p < 0.001). There was no significant relationship between ISCP and epigenetic age acceleration from Horvath, Hannum, and PhenoAge clocks (p > 0.05). Mediation analysis showed that an association between ISCP and pain severity and interference was mediated by the pace of biological aging (p <= 0.001). We further found that race moderated the indirect effect of ISCP on pain severity and interference, with ISCP being a stronger positive predictor of the pace of biological aging for non-Hispanic Blacks (NHBs) than for non-Hispanic Whites (NHWs). Future bio-behavioral interventions targeting internalized stigma surrounding chronic pain at various levels are necessary. A deeper understanding of the biological aging process could lead to improvements in managing nonspecific chronic low back pain (CLBP), particularly within underserved minority populations.