Lower Extremity Peripheral Artery Disease and Quality of Life among Older Individuals in the Community: The Atherosclerosis Risk in Communities (ARIC) Study

Background: Lower extremity peripheral arterial disease (PAD), commonly identified by an ankle-brachial Index (ABI) <0.9, increases mortality risk and may impair quality of life (QOL). However, most studies assessing reduced QOL in the relation to PAD rely on small clinical studies, leaving uncertainty about the impact of PAD on QOL in the community. Methods: Using data of 5,115 ARIC visit 5 (2011-2013) participants aged 66-90 years, we assessed the associations of ABI with several QOL parameters, including physical and mental components in SF-12 as well as some other QOL parameters (leisure time exercise/activity/walking, depression, and hopeless feeling. We used linear/logistic regression models to adjust for demographic characteristics, cardiovascular disease (CVD) risk factors, history of CVD, and other comorbidities including lung disease and reduced kidney function. Results: There were 402 participants with low ABI < 0.90 and 426 participants with borderline low ABI (0.90-0.99). Overall, there were dose-response relationships between lower ABI and poor status of QOL parameters. With ABI 1.10-1.19 as a reference (n=1900), the associations of low ABI (< 0.90) and impaired QOL were much more evident in physical components (Physical Component Summary: -3.27 [95%CI: -5.60 to -0.93]), compared to mental components (Mental Component Summary: -0.07 [95%CI: -2.21 to 2.06]). Regarding each of eight domains in SF-12, low ABI was significantly associated with all four domains for physical components (Physical Functioning, Role Physical, Bodily Pain, and General Health) but only with one of four domains for mental components (vitality). Similarly low ABI was more consistently associated with the other physical QOL parameters than the other mental parameters. Interestingly, a poor status of several QOL parameters was also observed in borderline low ABI. Similar results for lower ABI and physical QOL parameters were observed in subgroups according to sex, race as well as history of CVD, diabetes, and reduced kidney function. Conclusions: Lower ABI was independently associated with poor status of QOL, especially on physical, with potential important implications on quality-maintained life in older individuals. Further studies are warranted to assess if the PAD-specific management can improve QOL among individuals with lower ABI

Lower Extremity Peripheral Artery Disease and Quality of Life Among Older Individuals in the Community

BACKGROUND: Evidence regarding the association of lower extremity peripheral arterial disease with quality of life (QOL) is mainly from selected clinical populations or relatively small clinical cohorts. Thus, we investigated this association in community-derived populations. METHODS AND RESULTS: Using data of 5115 participants aged 66 to 90 years from visit 5 (2011-2013) of the Atherosclerosis Risk in Communities Study, we quantified the associations of ankle-brachial index (ABI) with several QOL parameters, including 12-item Short-Form Health Survey (SF-12), after accounting for potential confounders using linear and logistic regression models. Peripheral arterial disease defined by an ABI <0.90 (n=402), was independently associated with a low SF-12 Physical Component Summary score (-3.26 [95% CI -5.60 to -0.92]), compared to the ABI reference 1.10 to 1.19 (n=1900) but not with the Mental Component Summary score (-0.07 [-2.21 to 2.06]). A low ABI was significantly associated with poorer status of all SF-12 physical domains (physical functioning, role-physical, bodily pain, and general health) but only vitality out of 4 mental domains. Similarly, low ABI values were more consistently associated with other physically related QOL parameters (leisure-time exercise/activity/walking) than mentally related parameters (significant depressive symptoms and hopeless feeling). Lower physical QOL was observed even in individuals with borderline low ABI (0.90 to 0.99; n=426). CONCLUSIONS: Low ABI (even borderline) was independently associated with poor QOL, especially for physical components, in community-dwelling older adults. QOL is a critical element for older adults, and thus, further studies are warranted to assess whether peripheral arterial disease-specific management can improve QOL in older populations

Lower Extremity Peripheral Artery Disease and Quality of Life among Older Individuals in the Community: The Atherosclerosis Risk in Communities (ARIC) Study

Background: Lower extremity peripheral arterial disease (PAD), commonly identified by an ankle-brachial Index (ABI) <0.9, increases mortality risk and may impair quality of life (QOL). However, most studies assessing reduced QOL in the relation to PAD rely on small clinical studies, leaving uncertainty about the impact of PAD on QOL in the community. Methods: Using data of 5,115 ARIC visit 5 (2011-2013) participants aged 66-90 years, we assessed the associations of ABI with several QOL parameters, including physical and mental components in SF-12 as well as some other QOL parameters (leisure time exercise/activity/walking, depression, and hopeless feeling. We used linear/logistic regression models to adjust for demographic characteristics, cardiovascular disease (CVD) risk factors, history of CVD, and other comorbidities including lung disease and reduced kidney function. Results: There were 402 participants with low ABI < 0.90 and 426 participants with borderline low ABI (0.90-0.99). Overall, there were dose-response relationships between lower ABI and poor status of QOL parameters. With ABI 1.10-1.19 as a reference (n=1900), the associations of low ABI (< 0.90) and impaired QOL were much more evident in physical components (Physical Component Summary: -3.27 [95%CI: -5.60 to -0.93]), compared to mental components (Mental Component Summary: -0.07 [95%CI: -2.21 to 2.06]). Regarding each of eight domains in SF-12, low ABI was significantly associated with all four domains for physical components (Physical Functioning, Role Physical, Bodily Pain, and General Health) but only with one of four domains for mental components (vitality). Similarly low ABI was more consistently associated with the other physical QOL parameters than the other mental parameters. Interestingly, a poor status of several QOL parameters was also observed in borderline low ABI. Similar results for lower ABI and physical QOL parameters were observed in subgroups according to sex, race as well as history of CVD, diabetes, and reduced kidney function. Conclusions: Lower ABI was independently associated with poor status of QOL, especially on physical, with potential important implications on quality-maintained life in older individuals. Further studies are warranted to assess if the PAD-specific management can improve QOL among individuals with lower ABI

Brain Lesions, Aspirin Use, and a Method to Address Attrition in Studying Risk Factors for Cognitive Decline and Dementia

Current dementia research faces multiple challenges. So far, there is no effective intervention, e.g., medication, for preventing dementia. When studying cognitive impairment, selection bias due to attrition may threaten the validity of study results. In addition, the specific brain pathological changes leading to dementia remain unclear. This dissertation addresses each of these issues by studying the association of brain morphological measurements and lesions with dementia risk, aspirin use as a preventative strategy, and methods to address differential cohort attrition in studying cognitive decline. In the study relating brain changes to dementia incidence, magnetic resonance imaging measurable signs were strong predictors for dementia risk. Alzheimer’s disease-specific pathology and vascular-related pathology have independent effects on dementia incidence; Alzheimer’s disease-specific pathology was associated with risk at all stages (risk of mild cognitive impairment (MCI), dementia, and conversion from MCI to dementia) while vascular changes were risk factors for MCI but not the progression from MCI to dementia. The study of aspirin found no association of regular aspirin use in late-middle age and old age with dementia, as well as with dementia-related brain morphological lesions except for an isolated association of long-term regular aspirin use with lower dementia risk. The results suggest a need for further investigation of regular aspirin use initiated at an early age and with long duration of use. Lastly, while trajectories of continuous measures of cognitive function are a promising approach to study decline more specifically, the validity of these analyses is threatened by informative losses. Therefore, we developed and applied an imputation-based analytical approach to reduce potential bias due to differential cohort attrition in estimating risk factor-cognitive decline associations. Dementia surveillance information was highly informative for imputing missing cognitive scores and validation studies suggest fully informed imputation yields unbiased estimates of cognitive function among dementia cases. Together the three studies advance our understanding of risk factors and methodologies in dementia research with the goal of improving prevention

Seismic Design and Performance Evaluation of Coupled Steel Plate and Reinforced Concrete Composite Walls

Coupled steel plate and reinforced concrete (SPRC) composite shear walls have been widely constructed in the core tube of super tall buildings in seismic regions. However, relevant research progress is far behind the practical application of this coupled composite wall system. Particularly, the current seismic design method does not consider the coupling mechanism and lacks efficiency in the computation of seismic base shear. In this research, the energy balance-based plastic design (EBPD) method is developed and used to design twelve prototype structures considering different structural heights and coupling ratios (CR). With the ABAQUS-based numerical techniques verified by relevant experimental results, all the prototype cases were studied by pushover analysis and nonlinear dynamic analysis to examine the effectiveness of the EBPD method in ensuring satisfactory seismic performance of coupled SPRC composite walls. The results indicate that the coupled SPRC composite walls designed by the EBPD method can satisfy the code requirements on lateral deformation under moderate and rare earthquakes. The analytical average story shear and bending moment distribution patterns have acceptable agreement with the relevant design assumptions. Favorable CR ranges are suggested for the coupled SPRC composite walls with different story numbers to achieve good earthquake-induced deformation characteristics

RC wall and steel side columns coupled structural system: Experimental and numerical investigations

The reinforced concrete (RC) wall coupled with steel side columns (SSC) using steel coupling beams were studied both experimentally and numerically. A 1/4 scaled 5-story test model was constructed and tested to failure under reversed lateral cyclic and constant axial loads. Test results proved that the coupling mechanism can be effectively realized in this unique coupled structural system involving only one wall pier. In order to reveal more seismic response characteristics in addition to the test results, numerical parametric studies were conducted based on the validated finite element modeling techniques. Results indicate the medium levels of axial load ratio and span-to-depth ratio of the steel coupling beam, or low level of wall aspect ratio, can lead to acceptable lateral load capacity and displacement ductility of the RC wall and SSC coupled structural system

Data from: Systemic inflammation during midlife and cognitive change over 20 years: the ARIC study

Objective: To examine the association between systemic inflammation measured during midlife and 20-year cognitive decline. Methods: Within the Atherosclerosis Risk in Communities cohort study, inflammatory biomarkers were measured during middle adulthood. We created an inflammation composite score using four blood biomarkers measured at Visit 1 (fibrinogen, white blood cell count, von Willebrand factor, and Factor VIII); we measured C-reactive protein (CRP) at Visit 2. Cognition was assessed over three visits spanning 20 years using measures of memory, executive function, and language. Results: 12,336 participants (baseline age 56.8 [5.7], 21% black, 56% women) were included. After adjusting for demographic variables, vascular risk factors and comorbidities, each standard deviation (SD) increase in midlife inflammation composite score was associated with an additional 20-year decline of -0.035 SD (95% CI: -0.062, -0.007) on the cognitive composite score. We found a similar association between each SD increase in midlife CRP level and additional 20-year cognitive decline (-0.038 SD, 95% CI: -0.057, -0.019). Participants with a midlife inflammation composite score in the top quartile had a 7.8% steeper cognitive decline, compared to participants in the lowest quartile; CRP in the top quartile was associated with an 11.6% steeper cognitive decline. In cognitive domain-specific analyses, elevated midlife inflammatory markers were most consistently associated with declines in memory. Results were similar after adjusting for attrition using inverse probability weighting. Conclusions: Our findings highlight what may be an early pathogenic role for systemic inflammation as a driver of cognitive decline in the decades leading up to older adulthood

Data from: Systemic inflammation during midlife and cognitive change over 20 years: the ARIC study

Objective: To examine the association between systemic inflammation measured during midlife and 20-year cognitive decline. Methods: Within the Atherosclerosis Risk in Communities cohort study, inflammatory biomarkers were measured during middle adulthood. We created an inflammation composite score using four blood biomarkers measured at Visit 1 (fibrinogen, white blood cell count, von Willebrand factor, and Factor VIII); we measured C-reactive protein (CRP) at Visit 2. Cognition was assessed over three visits spanning 20 years using measures of memory, executive function, and language. Results: 12,336 participants (baseline age 56.8 [5.7], 21% black, 56% women) were included. After adjusting for demographic variables, vascular risk factors and comorbidities, each standard deviation (SD) increase in midlife inflammation composite score was associated with an additional 20-year decline of -0.035 SD (95% CI: -0.062, -0.007) on the cognitive composite score. We found a similar association between each SD increase in midlife CRP level and additional 20-year cognitive decline (-0.038 SD, 95% CI: -0.057, -0.019). Participants with a midlife inflammation composite score in the top quartile had a 7.8% steeper cognitive decline, compared to participants in the lowest quartile; CRP in the top quartile was associated with an 11.6% steeper cognitive decline. In cognitive domain-specific analyses, elevated midlife inflammatory markers were most consistently associated with declines in memory. Results were similar after adjusting for attrition using inverse probability weighting. Conclusions: Our findings highlight what may be an early pathogenic role for systemic inflammation as a driver of cognitive decline in the decades leading up to older adulthood

Association of NTproBNP and cTnI with outpatient sudden cardiac death in hemodialysis patients: the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study.

BackgroundSudden cardiac death (SCD) is the most common etiology of death in hemodialysis patients but not much is known about its risk factors. The goal of our study was to determine the association and risk prediction of SCD by serum N-terminal prohormone of brain natriuretic peptide (NTproBNP) troponin I (cTnI) in hemodialysis patients.MethodsWe measured NTproBNP and cTnI in 503 hemodialysis patients of a national prospective cohort study. We determined their association with SCD using Cox regression, adjusting for demographics, co-morbidities, and clinical factors and risk prediction using C-statistic and Net Reclassification Improvement (NRI).ResultsPatients' mean age was 58&nbsp;years and 54&nbsp;% were male. During follow-up (median 3.5&nbsp;years), there were 75 outpatient SCD events. In unadjusted and fully-adjusted models, NTproBNP had a significant association with the risk of SCD. Analyzed as a continuous variable, the risk of SCD increased 27&nbsp;% with each 2-fold increase in NTproBNP (HR, 1.27 per doubling; 95&nbsp;% CI, 1.13-1.43; p &lt; 0.001). In categorical models, the risk of SCD was 3-fold higher in the highest tertile of NTproBNP (&gt;7,350&nbsp;pg/mL) compared with the lowest tertile (&lt;1,710&nbsp;pg/mL; HR for the highest tertile, 3.03; 95&nbsp;% CI, 1.56-5.89; p = 0.001). Higher cTnI showed a trend towards increased risk of SCD in fully adjusted models, but was not statistically significant (HR, 1.17 per doubling; 95&nbsp;% CI, 0.98-1.40; p = 0.08). Sensitivity analyses using competing risk models showed similar results. Improvement in risk prediction by adding cardiac biomarkers to conventional risk factors was greater with NTproBNP (C-statistic for 3-year risk: 0.810; 95&nbsp;% CI, 0.757 to 0.864; and continuous NRI: 0.270; 95&nbsp;% CI, 0.046 to 0.495) than with cTnI.ConclusionsNTproBNP is associated with the risk of SCD in hemodialysis patients. Further research is needed to determine if biomarkers measurement can guide SCD risk prevention strategies in dialysis patients