Ethnic differences in pain tolerance: clinical implications in a chronic pain population.

OBJECTIVE Although numerous studies have independently examined ethnic differences in clinical and experimental pain, few have investigated differences in both sensitivity to controlled noxious stimuli and clinical pain reports in the same sample. The present experiment examined the effects of ethnicity (African American vs. white) on experimental pain tolerance and adjustment to chronic pain. METHODS Three hundred thirty-seven (68 African American and 269 white) patients with chronic pain referred to a multidisciplinary treatment center participated in the study. In addition to completing a number of standardized questionnaires assessing adjustment to chronic pain, participants underwent a submaximal effort tourniquet procedure. This experimental pain procedure yields a measure of tolerance for a controlled noxious stimulus (ie, arm ischemia). RESULTS African American subjects reported higher levels of clinical pain as well as greater pain-related disability than white participants. In addition, substantial group differences were observed for ischemic pain tolerance, with African Americans demonstrating less tolerance than whites. Correlational analyses revealed a small but significant inverse relationship between ischemic pain tolerance and the reported severity of chronic pain. CONCLUSIONS Collectively these findings support previous research revealing ethnic differences in responses to both clinical and experimental pain. Moreover, the present results suggest that enhanced sensitivity to noxious stimuli on the part of African Americans may be associated with ethnic differences in reported clinical pain, although the magnitude of ethnic differences was much greater for ischemic pain tolerance than for clinical pain measures.