Sleep symptoms were associated with multiple sociodemographic and economic factors, though these relationships differed by predictor and sleep outcome. Also, reports depended on question wording.
Objective
Knee osteoarthritis (OA) contributes significantly to disability in older individuals and racial/ethnic minorities are disproportionately affected. The present study aimed to characterize differences in clinical and experimental pain including pain inhibition among older African-Americans (AAs) and non-Hispanic whites (NHWs) with knee OA.
Methods
AAs and NHWs with knee OA (n=267) completed clinical and functional pain assessments including quantitative sensory testing (QST). We hypothesized that 1) AAs would display lower pain tolerance and higher heat, mechanical and cold pain ratings compared to NHWs; 2) AAs would display greater temporal summation compared to NHWs; 3) AAs would display reduced pain inhibition compared to NHWs; 4) AAs would demonstrate greater clinical pain and poorer function relative to NHWs; and 5) QST would significantly predict clinical pain within each race/ethnicity.
Results
AAs displayed increased pain sensitivity, temporal summation and reduced pain inhibition than NHWs. AAs reported greater clinical pain and poorer function than NHWs. Race/ethnic differences in clinical pain became non-significant when controlling for education and income, whereas differences in QST remained highly significant. Although pain inhibition predicted clinical pain in both groups, different QST measures were additionally predictive of clinical pain within groups.
Conclusion
Our study establishes race/ethnic differences in experimental and clinical pain and function in older individuals with knee OA. Our findings that different QST measures were associated with clinical pain within race/ethnic groups while reduced pain inhibition was important in all participants warrants further study evaluating common and group-specific pathophysiological mechanisms contributing to clinical pain in OA.
Beyond relevant covariates, over a 10-year follow-up, longer objective sleep duration was longitudinally and significantly associated with a poorer lipid profile. Greater objective sleep fragmentation and self-reported poor sleep quality were not related to a poorer lipid profile.
The study determined the prevalence of sleep disorders by ethnicity and sex, and related daytime functioning, working memory, and mental health among older adolescent to emerging adult college students. Participants were U.S.A. undergraduates (N = 1684), aged 17–25, recruited from 2010 to 2011. Participants completed online questionnaires for all variables. Overall, 36.0% of the sample screened positive for sleep disorders with insomnia, restless legs syndrome, and periodic limb movement disorder being the most prevalent. Women reported more insomnia and daytime impairment. African–Americans reported more early morning awakenings and less daytime impairment. Students with insomnia symptoms or restless legs syndrome tended to have lower working memory capacities. Students with nightmares or parasomnias had greater odds for mental disorders. In an older adolescent to emerging adult college student sample, sleep disorders may be a common source of sleep disturbance and impairment. Certain sleep disorders may be associated with lower working memory capacity and poor mental health.
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