Table 1 includes the sample characteristics by race and sex. Mean age for Black participants was 63.9 years (SD: 10.5) and 64.2 years (SD: 10.2) for White participants. There were no significant between-group differences in age. White females had higher BMI (d = 0.57), and lower trait anxiety (d = −0.66) than Black females, while White males had lower BMI (d = −0.91) than Black males. Stratified analyses by sex demonstrated that Black females reported experiencing pain intensity ratings of all three intensity sensations at lower temperatures than White females, especially for “weak/mild pain” (mean ± SD: 35.0 ± 2.2 vs. 40.3 ± 2.3, p = 0.002 (21), d = 2.58), respectively. In contrast, Black males reported similar intensity pain ratings at all three intensity sensations as White males. There were no statistically significant differences for unpleasantness scores. However, Black participants reported higher scores for “just noticeable” pain unpleasantness and lower scores for “weak/mild” and “moderate” pain unpleasantness. These differences were of small to medium effect sizes with absolute temperature differences at 0.9–1.5 degrees (Table 1).

Though a relatively small sample, the current exploratory pilot results support and extend previously conducted research on race, sex, and pain. Established literature indicates that females are generally more sensitive to pain, have more pain related diagnoses, and report pain as more intense (5). However, the focus of most research on sex differences in pain does not include race as a primary predictor variable and similarly most research on racial differences in pain does not include within sex as a group comparison (5, 7).

Current pilot results support the notion that the interaction of race and sex may have important effects when designing future studies and preparing clinical practice guidelines. Overall, the current study demonstrated patterns of experimental pain responses, similar to previous research (6, 7). Similar to overall findings by race from Portenoy et al., when subdivided by sex in the current study, Black females were more sensitive to pain than White females (21). Although preliminary, the relationship between pain differences among Black and White females was robust. However, our sample size did not have sufficient power to detect statistically significant associations for effect size that are smaller than 1.8. For example, the racial differences of just noticeable unpleasantness pain scores were of medium to large effect sizes for both females and males (d = −0.56 and −0.72, respectively), even though the differences did not reach statistical significance (p = 0.42 and 0.28, respectively). Therefore, we reported both effect sizes and statistical p-values to guide results interpretation. Because of the small size we did not adjust for demographic and behavioral covariates (e.g., Age, SES, BMI, anxiety).

These pilot findings will inform future research that should seek to determine whether these findings are supported in a larger study including multiple psychophysical tests (e.g., threshold, tolerance, temporal summation, conditioned pain modulation) and multiple experimental pain measures (e.g., thermal, mechanical pressure, cold pressure, electrical shock). In addition to added experimental psychophysical procedures, more studies are needed to determine the impact and presence of geriatric co-morbidities that affect pain perception and intensity, which may differ by race and sex (e.g., cancer, diabetes, osteoarthritis). Thus, additional experimental and clinical studies of pain are needed in larger samples to provide more evidence to inform assessment and treatment of pain in racially diverse groups of male and female adults.

Because this study included mostly older adults and were purposefully age-matched, generalizability of findings is limited. To improve our understanding of the pain experience and pain mechanisms in this population, future studies using neuroimaging and mixed-methods approaches are needed.

Assessment and management of pain can be optimized when healthcare providers, such as nurses and physicians are able to better understand pain intensity and unpleasantness differences in adults from diverse sex and racial backgrounds. This is a necessary first step to ensure optimal quality of life through improvements in pain management for all adults, regardless of their sex or race.

The datasets used and/or analyzed during the current study are available from the senior author on reasonable request. Requests to access these datasets should be directed to Todd Monroe (monroe.1181@osu.edu).

The studies involving human participants were reviewed and approved by Vanderbilt University Institutional Review Board. The patients/participants provided their written informed consent to participate in this study.

KM: investigation, writing—original draft, writing—review and editing, visualization, and project administration. KW, KR, DS, TG, and MF: writing—review and editing and visualization. AT: formal analysis, resources, data curation, writing—review and editing, and visualization. RC: conceptualization, methodology, validation, writing—review and editing, visualization, and funding acquisition. TM: conceptualization, methodology, validation, investigation, resources, writing—original draft, visualization, supervision, project administration, and funding acquisition. All authors contributed to the article and approved the submitted version.

Data accessed for this project were combined from studies supported by the National Institutes of Health, National Institute on Aging projects K23 AG046379 and R21 AG049332.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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