Mechanisms of the Native American pain inequity: predicting chronic pain onset prospectively at 5 years in the Oklahoma Study of Native American Pain Risk.

Abstract: A pain inequity exists for Native Americans (NAs), but the mechanisms are poorly understood. The Oklahoma Study of Native American Pain Risk (OK-SNAP) addressed this issue and recruited healthy, pain-free NAs and non-Hispanic Whites (NHWs) to attend 2 laboratory visits and assessed mechanisms consistent with the biopsychosocial model of pain: demographics, physical variables, psychosocial factors, and nociceptive/pain phenotypes. Then participants were surveyed every 6 months to assess for chronic pain onset. Results at the 2-year follow-up found that NAs were ∼3x more likely than NHWs to develop chronic pain. Moreover, psychosocial factors (discrimination, stress, pain-related anxiety), cardiometabolic load (higher body mass index and blood pressure, lower heart rate variability), and impaired inhibition of spinal nociception partly mediated the pain inequity. The present study examined mechanisms of chronic pain at the 5-year follow-up for OK-SNAP. Results found that the NA pain inequity worsened-NAs were 4x more likely to develop chronic pain (OR = 4.025; CI = 1.966, 8.239), even after controlling for baseline age, sex assigned at birth, income, and education. Moreover, serial mediation models replicated paths from the 2-year follow-up that linked psychosocial variables, cardiometabolic load, and impaired inhibition of spinal nociception to chronic pain onset. Further, 2 new significant paths were observed. One linked discrimination, stress, sleep problems, and facilitated pain perception to increased pain risk. The other linked discrimination with higher spinal nociceptive threshold and pain risk. These results provide further evidence for a NA pain inequity and identify multiple psychosocial, cardiometabolic, and pronociceptive targets for primary interventions.