Racial Differences in Performance-Based Function and Potential Explanatory Factors Among Individuals With Knee Osteoarthritis.

OBJECTIVE: In individuals with knee osteoarthritis (OA), self-reported physical function is poorer in African Americans than in whites, but whether this difference holds true for objective assessments is unclear. The purpose of this study was to examine racial differences in performance-based physical function as well as potential underlying factors contributing to these racial differences. METHODS: Participants with knee OA from a randomized controlled trial completed the 2-minute step test (2MST), timed-up-and-go (TUG), and 30-second chair stand (30s-CST) at baseline. Race differences in performance-based function were assessed by logistic regression. Separate models were adjusted for sets of demographic, socioeconomic, psychological health, and physical health variables. RESULTS: In individuals with knee OA (n = 322; 72% women, 22% African American, mean ± SD age 66 ± 11 years, mean ± SD body mass index 31 ± 8 kg/m2 ), African Americans (versus whites) had greater unadjusted odds of poorer function (30s-CST odds ratio [OR] 2.79 [95% confidence interval (95% CI) 1.65-4.72], 2MST OR 2.37 [95% CI 1.40-4.03], and TUG OR 3.71 [95% CI 2.16-6.36]). Relationships were maintained when adjusted for demographic and psychological health covariates, but they were either partially attenuated or nonsignificant when adjusted for physical health and socioeconomic covariates. CONCLUSION: African American adults with knee OA had poorer unadjusted performance-based function than whites. Physical health and socioeconomic characteristics diminished these differences, emphasizing the fact that these factors may be important to consider in mitigating racial disparities in function.

Contributions of symptomatic osteoarthritis and physical function to incident cardiovascular disease.

BACKGROUND: Osteoarthritis (OA) is associated with worsening physical function and a high prevalence of comorbid health conditions. In particular, cardiovascular disease (CVD) risk is higher in individuals with OA than the general population. Limitations in physical function may be one pathway to the development of CVD among individuals with OA. This study evaluated associations of symptomatic knee OA (sxKOA), baseline physical function and worsening of function over time with self-reported incident CVD in a community-based cohort. METHODS: Our sample consisted of individuals from the Johnston County Osteoarthritis Project who did not report having CVD at baseline. Variables used to evaluate physical function were the Health Assessment Questionnaire (HAQ), time to complete 5 chair stands, and the 8-ft walk. Worsening function for these variables was defined based on previous literature and cutoffs from our sample. Logistic regression analyses examined associations of sxKOA, baseline function and worsening of function over time with self-reported incident CVD, unadjusted and adjusted for relevant demographic and clinical characteristics. RESULTS: Among 1709 participants included in these analyses, the mean age was 59.5 ± 9.5 years, 63.6% were women, 15% had sxKOA, and the follow up time was 5.9 ± 1.2 years. About a third of participants reported worsening HAQ score, about two-fifths had worsened chair stand time, half had worsened walking speed during the 8-ft walk, and 16% self-reported incident CVD. In unadjusted analyses, sxKOA, baseline function, and worsening function were all associated with self-reported incident CVD. In multivariable models including all of these variables, sxKOA was not associated with incident CVD, but worsening function was significantly associated with increased CVD risk, for all three functional measures: HAQ odds ratio (OR) = 2.49 (95% confidence interval (CI) 1.90-3.25), chair stands OR = 1.58 (95% CI 1.20-2.08), 8-ft walk OR = 1.53 (95%CI 1.15-2.04). These associations for worsening function remained in models additionally adjusted for demographic and clinical characteristics related to CVD risk. CONCLUSIONS: The association between symptomatic knee osteoarthritis and cardiovascular disease risk was explained by measures of physical function. This highlights the importance of physical activity and other strategies to prevent functional loss among individuals with symptomatic knee osteoarthritis.

Effect of laser-induced crater depth in laser-induced breakdown spectroscopy emission features.

The influence of crater depth on plasma properties and laser-induced breakdown spectroscopy (LIBS) emission has been evaluated. Laser-induced plasmas were generated at the surface and at the bottom of different craters in a copper sample. Plasmas produced at the sample surface and at the bottom of the craters were spatially and temporally resolved. LIBS emission, temperature, and electronic number density of the plasmas were evaluated. It is shown that the confinement effect produced by the craters enhances the LIBS signal from the laser-induced plasmas.

Application of laser-induced breakdown spectroscopy technique to hair tissue mineral analysis.

The concentration of the main minerals present in human hair is measured on several subjects by Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) and compared with the results obtained through a commercial analytical laboratory. The possibility of using CF-LIBS for mineral analysis in hair is discussed, as well as its feasibility for the fast and inexpensive determination of the occurrence of heavy-metal poisoning in hair.