179 research outputs found

    Lossy/Lossless Floating/Grounded Inductance Simulation Using One DDCC

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    In this work, we present new topologies for realizing one lossless grounded inductor and two floating, one lossless and one lossy, inductors employing a single differential difference current conveyor (DDCC) and a minimum number of passive components, two resistors, and one grounded capacitor. The floating inductors are based on ordinary dual-output differential difference current conveyor (DO-DDCC) while the grounded lossless inductor is based one a modified dual-output differential difference current conveyor (MDO-DDCC). The proposed lossless floating inductor is obtained from the lossy one by employing a negative impedance converter (NIC). The non-ideality effects of the active element on the simulated inductors are investigated. To demonstrate the performance of the proposed grounded inductance simulator as an example, it is used to construct a parallel resonant circuit. SPICE simulation results are given to confirm the theoretical analysis

    Trends in Stroke Incidence Rates in Older US Adults: An Update from the Atherosclerosis Risk in Communities (ARIC) Cohort Study

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    Importance: Determining whether the previously reported decreased stroke incidence rates from 1987 to 2011 among US adults 65 years and older in the Atherosclerosis Risk in Communities (ARIC) study continued to decrease subsequently can help guide policy and planning efforts. Objective: To evaluate whether stroke incidence declines among older adults in the ARIC study continued after 2011. Design, Setting, and Participants: ARIC is a community-based prospective cohort study including 15792 individuals aged 45 to 64 years at baseline (1987-1989), selected by probability sampling from residents of Forsyth County, North Carolina; Jackson, Mississippi (black individuals only); the northwestern suburbs of Minneapolis, Minneapolis; and Washington County, Maryland (ie, center). The present study included ARIC participants free of stroke at baseline, followed up through December 31, 2017. Data were collected through personal interviews and physical examinations during study visits, annual/semiannual telephone interviews, and active surveillance of discharges from local hospitals. Stroke events were adjudicated by study-physicians reviewers. Analysis began September 2018. Main Outcomes and Measures: The main outcome was stroke incidence rates, which were computed with 95% CIs stratifying the analysis by age and calendar time. Trends in adjusted incidence rates were assessed using Poisson regression incidence rate ratios. Models included calendar time, age, sex, race/center, and time-varying risk factors (hypertension, diabetes, coronary heart disease, cholesterol-lowering medication use, and smoking). Results: Of 14357 ARIC participants with 326654 person-years of follow-up, the mean (SD) age at baseline was 54.1 (5.8) years and 7955 (55.4%) were women. From 1987 to 2017, a total of 1340 incident strokes occurred among ARIC participants, and among them, 1028 (76.7%) occurred in participants 65 years and older. Crude incidence rates of stroke for participants 65 years and older decreased progressively from 1987 to 2017. Incidence rates, adjusted for age, sex, race/center, and time-varying risk factors, decreased by 32% (95% CI, 23%-40%) per 10 years in participants 65 years and older. Findings were consistent across decades, sex, and race. Conclusions and Relevance: Validated total stroke incidence rates in adults 65 years and older decreased over the last 30 years in the ARIC cohort. The decrease in rates previously reported for 1987 to 2011 extends for the subsequent 6 years in men and women as well as in white and black individuals

    Spousal influence on physical activity in middle-aged and older adults

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    Low physical activity levels are a public health concern. Few studies have assessed the concordance of physical activity change among spouses. We studied this concordance during a 6-year period (baseline: 1987-1989; follow-up: 1993-1995) in 3,261 spousal pairs from the US-based Atherosclerosis Risk in Communities (ARIC) Study. Linear regression was used to examine the association between change in individuals' sport/exercise and leisure physical activity indices (ranging from 1 (low) to 5 (high)) and change in his or her spouse's indices. The association between individual and spousal changes in meeting physical activity recommendations was assessed with logistic regression. Individual changes in the sport/exercise and leisure indices were positively associated with spousal changes. For every standard deviation increase in their wives' sport/exercise index, men's exercise index increased by 0.09 (95% confidence interval: 0.05, 0.12) standard deviation; for every standard deviation increase in their wives' leisure index, men's leisure index increased by 0.08 standard deviation. Results were similar for women. Individuals had higher odds of meeting physical activity recommendations if their spouse met recommendations at both visits or just follow-up. In conclusion, changes in an individual's physical activity are positively associated with changes in his or her spouse's physical activity. Physical activity promotion efforts should consider targeting couples

    Prestroke Physical Activity and Adverse Health Outcomes after Stroke in the Atherosclerosis Risk in Communities Study

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    Background and Purpose: The association of physical activity (PA) before stroke (prestroke PA) with long-term prognosis after stroke is still unclear. We examined the association of prestroke PA with adverse health outcomes in the ARIC study (Atherosclerosis Risk in Communities). Methods: We included 881 participants with incident stroke occurring between 1993 and 1995 (visit 3) and December 31, 2016. Follow-up continued until December 31, 2017 to allow for at least 1-year after incident stroke. Prestroke PA was assessed using a modified version of the Baecke questionnaire in 1987 to 1989 (visit 1) and 1993 to 1995 (visit 3), evaluating PA domains (work, leisure, and sports) and total PA. We used Cox proportional hazards models to quantify the association between tertiles of accumulated prestroke PA levels over the 6-year period between visits 1 and 3 and mortality, risk of cardiovascular disease, and recurrent stroke after incident stroke. Results: During a median follow-up of 3.1 years after incident stroke, 676 (77%) participants had adverse outcomes. Highest prestroke total PA was associated with decreased risks of all-cause mortality (hazard ratio, 0.78 [95% CI, 0.63-0.97]) compared with lowest tertile. In the analysis by domain-specific PA, highest levels of work PA were associated with lower risk for all-cause (hazard ratio, 0.77 [95% CI, 0.62-0.96]) and cardiovascular mortality (hazard ratio, 0.45 [95% CI, 0.29-0.70]), and highest levels of leisure PA were associated with lower all-cause mortality (hazard ratio, 0.72 [95% CI, 0.58-0.89]) compared with lowest tertile of PA. No significant associations for sports PA were observed. Conclusions: Higher levels of total prestroke PA as well as work and leisure PA were associated with lower risk of mortality after incident stroke. Public health strategies to increase lifetime PA should be encouraged to decrease long-term mortality after stroke

    Temporal trends in validated ischaemic stroke hospitalizations in the USA

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    Background: Accurate assessment of the burden of stroke, a major cause of disability and death, is crucial. We aimed to estimate rates of validated ischaemic stroke hospitalizations in the USA during 1998-2011. Methods: We used the Atherosclerosis Risk in Communities (ARIC) study cohort's adjudicated stroke data for participants aged ≥55 years, to construct validation models for each International Classification of Diseases (ICD)-code group and patient covariates. These models were applied to the Nationwide Inpatient Sample (NIS) data to estimate the probability of validated ischaemic stroke for each eligible hospitalization. Rates and trends in NIS using ICD codes vs estimates of validated ischaemic stroke were compared. Results: After applying validation models, the estimated annual average rate of validated ischaemic stroke hospitalizations in the USA during 1998-2011 was 3.37 [95% confidence interval (CI): 3.31, 3.43) per 1000 person-years. Validated rates declined during 1998-2011 from 4.7/1000 to 2.9/1000; however, the decline was limited to 1998-2007, with no further decline subsequently through 2011. Validation models showed that the false-positive (∼23% of strokes) and false-negative rates of ICD-9-CM codes in primary position for ischaemic stroke approximately cancel. Therefore, estimates of ischaemic stroke hospitalizations did not substantially change after applying validation models. Conclusions: Overall, ischaemic stroke hospitalization rates in the USA have declined during 1998-2007, but no further decline was observed from 2007 to 2011. Validated ischaemic stroke hospitalizations estimates were similar to published estimates of hospitalizations with ischaemic stroke ICD codes in primary position. Validation of national discharge data using prospective chart review data is important to estimate the accuracy of reported burden of stroke

    Prognostic Variation Among Very High-Risk and High-Risk Individuals With Atherosclerotic Cardiovascular Disease

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    Given the availability of an effective but expensive lipid-lowering medication, proprotein convertase subtilisin/kexin type 9 inhibitors, the American Heart Association and the American College of Cardiology 2018 cholesterol guideline introduced a new classification of “very high-risk” (i.e., multiple major atherosclerotic cardiovascular diseases [ASCVDs] or a major ASCVD þ multiple high-risk conditions) versus “high-risk” for patients with prior ASCVD. A few recent studies reported risk variation within very high-risk ASCVD, with multiple ASCVDs conferring higher risk than 1 ASCVD þ $2 high-risk conditions. However, these studies did not evaluate whether the constellation of high-risk conditions in 1 ASCVD may equate to the risk of multiple ASCVDs or whether the new classification has implications for heart failure

    Longitudinal Associations between Income Changes and Incident Cardiovascular Disease: The Atherosclerosis Risk in Communities Study

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    Importance: Higher income is associated with lower incident cardiovascular disease (CVD). However, there is limited research on the association between changes in income and incident CVD. Objective: To examine the association between change in household income and subsequent risk of CVD. Design, Setting, and Participants: The Atherosclerosis Risk In Communities (ARIC) study is an ongoing, prospective cohort of 15792 community-dwelling men and women, of mostly black or white race, from 4 centers in the United States (Jackson, Mississippi; Washington County, Maryland; suburbs of Minneapolis, Minnesota; and Forsyth County, North Carolina), beginning in 1987. For our analysis, participants were followed up until December 31, 2016. Exposures: Participants were categorized based on whether their household income dropped by more than 50% (income drop), remained unchanged/changed less than 50% (income unchanged), or increased by more than 50% (income rise) over a mean (SD) period of approximately 6 (0.3) years between ARIC visit 1 (1987-1989) and visit 3 (1993-1995). Main Outcomes and Measures: Our primary outcome was incidence of CVD after ARIC visit 3, including myocardial infarction (MI), fatal coronary heart disease, heart failure (HF), or stroke during a mean (SD) of 17 (7) years. Analyses were adjusted for sociodemographic variables, health behaviors, and CVD biomarkers. Results: Of the 8989 included participants (mean [SD] age at enrollment was 53 [6] years, 1820 participants were black [20%], and 3835 participants were men [43%]), 900 participants (10%) experienced an income drop, 6284 participants (70%) had incomes that remained relatively unchanged, and 1805 participants (20%) experienced an income rise. After full adjustment, those with an income drop experienced significantly higher risk of incident CVD compared with those whose incomes remained relatively unchanged (hazard ratio, 1.17; 95% CI, 1.03-1.32). Those with an income rise experienced significantly lower risk of incident CVD compared with those whose incomes remained relatively unchanged (hazard ratio, 0.86; 95% CI, 0.77-0.96). Conclusions and Relevance: Income drop over 6 years was associated with higher risk of subsequent incident CVD over 17 years, while income rise over 6 years was associated with lower risk of subsequent incident CVD over 17 years. Health professionals should have greater awareness of the influence of income change on the health of their patients

    Albuminuria and Prognosis Among Individuals With Atherosclerotic Cardiovascular Disease: The ARIC Study

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    The American College of Cardiology and the American Heart Association 2018 Cholesterol Guideline proposed the new classification of “very high-risk” atherosclerotic cardiovascular disease (ASCVD) (multiple ASCVDs or 1 ASCVD plus $2 high-risk conditions) to guide intensive secondary prevention. This guideline takes into account reduced glomerular filtration rate (GFR) as a high-risk condition, but not albuminuria, a measure of kidney damage, that is more strongly associated with cardiovascular outcomes than reduced GFR. Importantly, the assessment of albuminuria is already recommended in patients with diabetes and hypertension, and thus, data of albuminuria are readily available in many patients with ASCVD. We explored whether urine albumin-to-creatinine ratio (ACR) is independently associated with adverse outcomes and can improve risk prediction in persons with ASCVD beyond the high-risk conditions in the guideline

    Life's Simple 7 at Midlife and Risk of Recurrent Cardiovascular Disease and Mortality after Stroke: The ARIC study

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    Background: Stroke is a leading cause of morbidity and mortality among adults in the U.S. Ideal levels of the Life's Simple 7 (LS7) are associated with lower cardiovascular disease (CVD) and all-cause mortality. However, the association of LS7 with CVD, recurrent stroke, and all-cause mortality after incident stroke is unknown. Methods: We used data from the ARIC study, a cohort of 13,508 adults from four US communities, 45–64 years old at baseline (1987–1989). Cardiovascular hospitalizations and mortality were ascertained in follow-up through December 31st, 2017. We defined cardiovascular health (CVH) based on AHA definitions for LS7 (range 0-14) and categorized CVH into four levels: LS7 0-3, 4-6, 7-9, and ≥10 (ideal LS7), according to prior studies. Outcomes included incident stroke, CVD, recurrent stroke, all-cause mortality, and a composite outcome including all the above. Adjusted hazard ratios (95% CI) were estimated with Cox proportional hazards regression models. Results: Median (25%-75%) follow-up for incident stroke was 28 (18.6-29.2) years. Participants with incident stroke were 55.7 (SD 5.6) years-old at baseline, 53% were women and 35% Black. Individuals with LS7 score ≥10 had 65% lower risk (HR: 0.35; 95% CI: 0.29-0.41) of incident stroke than those with LS7 4-6 (reference group). Of 1,218 participants with incident stroke, 41.2% (n=502) had composite CVD and 68.3% (n=832) died during a median (25%-75%) follow-up of 4.0 (0.76-9.95) years. Adjusted HR (95% CI) for stroke survivors with LS7≥10 at baseline were 0.74 (0.58-0.94) for the composite outcome, 0.38(0.17-0.85) for myocardial infarction, 0.60 (0.40-0.90) for heart failure, 0.63 (0.48-0.84) for all-cause mortality, and 0.65 (0.39-1.08) for recurrent stroke. Conclusions: Good and excellent midlife cardiovascular health are associated with lower risks of incident stroke and CVD after stroke. Clinicians should stress the importance of a healthy lifestyle for primary and secondary CVD prevention

    Association of Ischemic Stroke Incidence, Severity, and Recurrence with Dementia in the Atherosclerosis Risk in Communities Cohort Study

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    Importance: Ischemic stroke is associated with increased risk of dementia, but the association of stroke severity and recurrence with risk of impaired cognition is not well known. Objective: To examine the risk of dementia after incident ischemic stroke and assess how it differed by stroke severity and recurrence. Design, Setting, and Participants: The Atherosclerosis Risk in Communities (ARIC) study is an ongoing prospective cohort of 15792 community-dwelling individuals from 4 US states (Mississippi, Maryland, Minnesota, and North Carolina). Among them, 15379 participants free of stroke and dementia at baseline (1987 to 1989) were monitored through 2019. Data were analyzed from April to October 2021. Associations between dementia and time-varying ischemic stroke incidence, frequency, and severity were studied across an average of 4.4 visits over a median follow-up of 25.5 years with Cox proportional hazards models adjusted for sociodemographic characteristics, apolipoprotein E, and vascular risk factors. Exposures: Incident and recurrent ischemic strokes were classified by expert review of hospital records, with severity defined by the National Institutes of Health Stroke Scale (NIHSS; minor, ≤5; mild, 6-10; moderate, 11-15; and severe, ≥16). Main Outcomes and Measures: Dementia cases adjudicated through expert review of in-person evaluations, informant interviews, telephone assessments, hospitalization codes, and death certificates. In participants with stroke, dementia events in the first year after stroke were not counted. Results: At baseline, the mean (SD) age of participants was 54.1 (5.8) years, and 8485 of 15379 participants (55.2%) were women. A total of 4110 participants (26.7%) were Black and 11269 (73.3%) were White. A total of 1378 ischemic strokes (1155 incident) and 2860 dementia cases were diagnosed 1 year or more after incident stroke in participants with stroke, or at any point after baseline in participants without stroke, were identified through December 31, 2019. NIHSS scores were available for 1184 of 1378 ischemic strokes (85.9%). Risk of dementia increased with both the number and severity of strokes. Compared with no stroke, risk of dementia by adjusted hazard ratio was 1.76 (95% CI, 1.49-2.00) for 1 minor to mild stroke, 3.47 (95% CI, 2.23-5.40) for 1 moderate to severe stroke, 3.48 (95% CI, 2.54-4.76) for 2 or more minor to mild strokes, and 6.68 (95% CI, 3.77-11.83) for 2 or more moderate to severe strokes. Conclusions and Relevance: In this study, risk of dementia significantly increased after ischemic stroke, independent of vascular risk factors. Results suggest a dose-response association of stroke severity and recurrence with risk of dementia
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