Ethnic differences in thermal pain responses

Objective: Although numerous studies have reported ethnic differences in the prevalence and severity of clinical pain, little is known about how these differences affect the perception of experimental pain. The present experiment examined the effects of ethnicity (African American vs. white) on thermal pain responses in a healthy undergraduate population. Methods: Thirty white subjects (16 women and 14 men) and 18 African Americans (10 women and 8 men) participated in the study. Thermal testing included evaluation of the following: warmth thresholds, thermal pain thresholds, thermal pain tolerances, and magnitude estimates of both the intensity and unpleasantness of thermal pain (at 46°, 47°, 48°, and 49°C). Results: Although no group differences emerged for warmth thresholds, thermal pain thresholds, or pain intensity ratings, African Americans demonstrated lower thermal pain tolerances than whites. In addition, African Americans had smaller slopes and larger intercepts than whites for ratings of pain unpleasantness. Additional analyses suggested that these findings were a consequence of group differences in thermal pain unpleasantness ratings at the lowest temperatures assessed (46°and 47°C); at these temperatures, African Americans rated the stimuli as more unpleasant than whites. Finally, group differences in thermal pain tolerance and thermal pain unpleasantness ratings seemed to partially account for greater self-reported daily pain symptoms among African Americans. Conclusions: Collectively, these findings seem to suggest ethnic differences in the perception of the affective-motivational dimension of thermal pain.