ASU Scholarship Showcase

Introduction: Individuals with osteoarthritis (OA) show increased morbidity and mortality. Telomere length, a measure of cellular aging, predicts increased morbidity and mortality. Telomeres shorten with persisting biological and psychosocial stress. Living with chronic OA pain is stressful. Previous research exploring telomere length in people with OA has produced inconsistent results. Considering pain severity may clarify the relationship between OA and telomeres.

Objectives: We hypothesized that individuals with high OA chronic pain severity would have shorter telomeres than those with no or low chronic pain severity.

Methods: One hundred thirty-six adults, ages 45 to 85 years old, with and without symptomatic knee OA were included in the analysis. Peripheral blood leukocyte telomere length was measured, and demographic, clinical, and functional data were collected. Participants were categorized into 5 pain severity groups based on an additive index of frequency, intensity, time or duration, and total number of pain sites (FITT). Covariates included age, sex, race or ethnicity, study site, and knee pain status.

Results: The no or low chronic pain severity group had significantly longer telomeres compared with the high pain severity group, P50.025. A significant chronic pain severity dose response emerged for telomere length, P50.034. The FITT chronic pain severity index was highly correlated with the clinical and functional OA pain measures. However, individual clinical and functional measures were not associated with telomere length.

Conclusion: Results demonstrate accelerated cellular aging with high knee OA chronic pain severity and provide evidence for the potential utility of the FITT chronic pain severity index in capturing the biological burden of chronic pain.

Objective: Survival time is an important type of outcome variable in treatment research. Currently, limited guidance is available regarding performing mediation analyses with survival outcomes, which generally do not have normally distributed errors, and contain unobserved (censored) events. We present considerations for choosing an approach, using a comparison of semi-parametric proportional hazards (PH) and fully parametric accelerated failure time (AFT) approaches for illustration.

Method: We compare PH and AFT models and procedures in their integration into mediation models and review their ability to produce coefficients that estimate causal effects. Using simulation studies modeling Weibull-distributed survival times, we compare statistical properties of mediation analyses incorporating PH and AFT approaches (employing SAS procedures PHREG and LIFEREG, respectively) under varied data conditions, some including censoring. A simulated data set illustrates the findings.

Results: AFT models integrate more easily than PH models into mediation models. Furthermore, mediation analyses incorporating LIFEREG produce coefficients that can estimate causal effects, and demonstrate superior statistical properties. Censoring introduces bias in the coefficient estimate representing the treatment effect on outcome—underestimation in LIFEREG, and overestimation in PHREG. With LIFEREG, this bias can be addressed using an alternative estimate obtained from combining other coefficients, whereas this is not possible with PHREG.

Conclusions: When Weibull assumptions are not violated, there are compelling advantages to using LIFEREG over PHREG for mediation analyses involving survival-time outcomes. Irrespective of the procedures used, the interpretation of coefficients, effects of censoring on coefficient estimates, and statistical properties should be taken into account when reporting results.

This randomized prospective trial aimed to assess the feasibility and efficacy of a team-based worksite health and safety intervention for law enforcement personnel. Four-hundred and eight subjects were enrolled and half were randomized to meet for weekly, peer-led sessions delivered from a scripted team-based health and safety curriculum. Curriculum addressed: exercise, nutrition, stress, sleep, body weight, injury, and other unhealthy lifestyle behaviors such as smoking and heavy alcohol use. Health and safety questionnaires administered before and after the intervention found significant improvements for increased fruit and vegetable consumption, overall healthy eating, increased sleep quantity and sleep quality, and reduced personal stress.

Abdominal obesity and insulin resistance (IR) place youth at higher risk for premature cardiovascular disease (CVD), but the underlying mechanisms are not clear. In adults, abdominal obesity and IR contribute to the oxidation of low-density lipoprotein (LDL). Whether similar mechanisms are operational in Latino adolescents is unknown. Therefore, we determined whether IR and abdominal adiposity are associated with higher oxLDL concentrations in Latino adolescents. Data from 123 Latino adolescents (16.3 ± 2.5 years; female = 74) were used for the present analysis. Participants were assessed for waist circumference, fasting serum oxLDL, and insulin sensitivity by the whole body insulin sensitivity index. In separate linear regression models adjusting for age and sex, both waist circumference and insulin sensitivity were significant predictors of oxLDL (β = 1.9; p = 0.002; R[superscript 2] = 0.13, β = −1.7; p = 0.006; R[superscript 2] = 0.11, respectively). When insulin sensitivity and waist circumference were included in the same model, both remained independent predictors of oxLDL (β = 1.7; p = 0.016 and, β = −1.5; p = 0.055, respectively; R[superscript 2] = 0.16). These results suggest that insulin resistance and abdominal adiposity are associated with higher levels of LDL oxidation which may be a mechanism contributing to increased CVD risk in Latino adolescents.

Background: The purpose of the study was to develop and test the initial psychometric properties of the ATTitudes and Avatars INstrument (ATTAIN). The integrated behavior model guided instrument development to measure the young adolescent boys’ attitudes, intentions and actions to change their bodies.

Methods: An adolescent health expert panel and young adolescent boys were recruited to test for content validity. Fifty-nine boys 11 to 14 years of age were recruited at a middle school in the USA during physical education class to conduct a pilot study to test for internal consistency and test-retest reliability.

Results: The ATTAIN was found to have high content validity, slightly below recommended levels for internal consistency, and varied test-retest reliability.

Conclusion: The long-term goal of the development and testing of the ATTAIN is to make it available to researchers and professionals to screen and focus on adolescents’ perceptions of their bodies and using those perceptions to attain and maintain healthy bodies. The results of this study suggest preliminarily a theoretically derived instrument with appropriate content for young adolescent boys and variable reliability. The attitudes, intentions, and actions survey items and avatars as measured by the ATTAIN, were meaningful to the boys. The ATTAIN has potential to be used as a screening instrument for young adolescents boys and understanding their attitudes toward their bodies; however, it will require continued development and testing to establish construct and discriminant validity.

Although previous research has studied power in mediation models, the extent to which the inclusion of a mediator will increase power has not been investigated. To address this deficit, in a first study we compared the analytical power values of the mediated effect and the total effect in a single-mediator model, to identify the situations in which the inclusion of one mediator increased statistical power. The results from this first study indicated that including a mediator increased statistical power in small samples with large coefficients and in large samples with small coefficients, and when coefficients were nonzero and equal across models. Next, we identified conditions under which power was greater for the test of the total mediated effect than for the test of the total effect in the parallel two-mediator model. These results indicated that including two mediators increased power in small samples with large coefficients and in large samples with small coefficients, the same pattern of results that had been found in the first study. Finally, we assessed the analytical power for a sequential (three-path) two-mediator model and compared the power to detect the three-path mediated effect to the power to detect both the test of the total effect and the test of the mediated effect for the single-mediator model. The results indicated that the three-path mediated effect had more power than the mediated effect from the single-mediator model and the test of the total effect. Practical implications of these results for researchers are then discussed.