Psychosocial and cardiometabolic predictors of chronic pain onset in Native Americans: serial mediation analyses of 2-year prospective data from the Oklahoma Study of Native American Pain Risk.

ABSTRACT: Chronic pain results in considerable suffering, as well as significant economic and societal costs. Prior evidence suggests that Native Americans (NAs) have higher rates of chronic pain than other U.S. racial/ethnic groups, but the mechanisms contributing to this pain disparity are poorly understood. The Oklahoma Study of Native American Pain Risk was developed to address this issue and recruited healthy, pain-free NAs and non-Hispanic Whites (NHWs). Cross-sectional analyses identified several measures of adversity (eg, trauma, discrimination), cognitive-affective factors (perceived stress, pain-related anxiety/catastrophizing), and cardiometabolic factors (eg, body mass index, blood pressure, heart rate variability) that were associated with pronociceptive processes (eg, central sensitization, descending inhibition, hyperalgesia). Every 6-months following enrollment, eligible participants (N=277) were recontacted and assessed for the onset of chronic pain. The present study examines predictors of chronic pain onset in the 222 (80%) who responded over the first 2-years. Results found that NAs developed chronic pain at a higher rate than NHWs (OR=2.902, p<.05), even after controlling for age, sex, income, and education. Moreover, serial mediation models identified several potential pathways to chronic pain onset within the NA group. These paths included perceived discrimination, psychological stress, pain-related anxiety, a composite measure of cardiometabolic risk, and impaired descending inhibition of spinal nociception (assessed from conditioned pain modulation of the nociceptive flexion reflex). These results provide the first prospective evidence for a pain disparity in NAs that seems to be promoted by psychosocial, cardiometabolic, and pronociceptive mechanisms.