Skeletal Muscle Adiposity and Lung Function Trajectory in the Severe Asthma Research Program.

Rationale: Extrapulmonary manifestations of asthma, including fatty infiltration in tissues, may reflect systemic inflammation and influence lung function and disease severity. Objectives: To determine if skeletal muscle adiposity predicts lung function trajectory in asthma. Methods: Adult SARP III (Severe Asthma Research Program III) participants with baseline computed tomography imaging and longitudinal postbronchodilator FEV1% predicted (median follow-up 5 years [1,132 person-years]) were evaluated. The mean of left and right paraspinous muscle density (PSMD) at the 12th thoracic vertebral body was calculated (Hounsfield units [HU]). Lower PSMD reflects higher muscle adiposity. We derived PSMD reference ranges from healthy control subjects without asthma. A linear multivariable mixed-effects model was constructed to evaluate associations of baseline PSMD and lung function trajectory stratified by sex. Measurements and Main Results: Participants included 219 with asthma (67% women; mean [SD] body mass index, 32.3 [8.8] kg/m2) and 37 control subjects (51% women; mean [SD] body mass index, 26.3 [4.7] kg/m2). Participants with asthma had lower adjusted PSMD than control subjects (42.2 vs. 55.8 HU; P < 0.001). In adjusted models, PSMD predicted lung function trajectory in women with asthma (ß = -0.47 Δ slope per 10-HU decrease; P = 0.03) but not men (ß = 0.11 Δ slope per 10-HU decrease; P = 0.77). The highest PSMD tertile predicted a 2.9% improvement whereas the lowest tertile predicted a 1.8% decline in FEV1% predicted among women with asthma over 5 years. Conclusions: Participants with asthma have lower PSMD, reflecting greater muscle fat infiltration. Baseline PSMD predicted lung function decline among women with asthma but not men. These data support an important role of metabolic dysfunction in lung function decline.

Effects of HIV Infection on Arterial Endothelial Function: Results From a Large Pooled Cohort Analysis.

OBJECTIVE: To determine the effects of HIV serostatus and disease severity on endothelial function in a large pooled cohort study of people living with HIV infection and HIV- controls. Approach and Results: We used participant-level data from 9 studies: 7 included people living with HIV (2 treatment-naïve) and 4 had HIV- controls. Brachial artery flow-mediated dilation (FMD) was measured using a standardized ultrasound imaging protocol with central reading. After data harmonization, multiple linear regression was used to examine the effects of HIV- serostatus, HIV disease severity measures, and cardiovascular disease risk factors on FMD. Of 2533 participants, 986 were people living with HIV (mean 44.4 [SD 11.8] years old) and 1547 were HIV- controls (42.9 [12.2] years old). The strongest and most consistent associates of FMD were brachial artery diameter, age, sex, and body mass index. The effect of HIV+ serostatus on FMD was strongly influenced by kidney function. In the highest tertile of creatinine (1.0 mg/dL), the effect of HIV+ serostatus was strong (ß=-1.59% [95% CI, -2.58% to -0.60%], P=0.002), even after covariate adjustment (ß=-1.36% [95% CI, -2.46% to -0.47%], P=0.003). In the lowest tertile (0.8 mg/dL), the effect of HIV+ serostatus was strong (ß=-1.90% [95% CI, -2.58% to -1.21%], P<0.001), but disappeared after covariate adjustment. HIV RNA viremia, CD4+ T-cell count, and use of antiretroviral therapy were not meaningfully associated with FMD. CONCLUSIONS: The significant effect of HIV+ serostatus on FMD suggests that people living with HIV are at increased cardiovascular disease risk, especially if they have kidney disease.

Effects of ultrasound technology advances on measurement of carotid intima-media thickness: A review.

In this review, we describe how technological advances in ultrasound imaging related to transducer construction and image processing fundamentally alter generation of ultrasound images to produce better quality images with higher resolution. However, carotid intima-media thickness (IMT) measurements made from images acquired on modern ultrasound systems are not comparable to historical population nomograms that were used to determine wall thickness thresholds that inform atherosclerotic cardiovascular disease risk. Because it is nearly impossible to replicate instrumentation settings that were used to create the reference carotid IMT nomograms and to place an individual's carotid IMT value in or above a clinically relevant percentile, carotid IMT measurements have a very limited role in clinical medicine, but remain a useful research tool when instrumentation, presets, image acquisition, and measurements can be standardized. In addition to new validation studies, it would be useful for the ultrasound imaging community to reach a consensus regarding technical aspects of ultrasound imaging acquisition, processing, and display for blood vessels so standard presets and imaging approaches could reliably yield the same measurements.

Associations Between Sleep Apnea and Subclinical Carotid Atherosclerosis: The Multi-Ethnic Study of Atherosclerosis.

Background and Purpose- Many health effects of sleep apnea (SA) may be mediated through accelerated atherosclerosis. We examined the associations of snoring and several measurements of SA with subclinical carotid atherosclerosis in a large multiethnic population sample. Methods- This analysis included 1615 participants (mean age, 68 years) from examination 5 (2010-2013) of the MESA study (Multi-Ethnic Study of Atherosclerosis). Sleep measures including SA (apnea-hypopnea index [4%], ≥15 events/hour) were derived from full in-home polysomnography. Carotid atherosclerosis was measured using high-resolution B-mode ultrasound. Multivariable linear and logistic regression models were used to evaluate the associations between sleep exposures with carotid intima-media thickness and the presence of carotid plaque, respectively. Effect modification by age, sex, and race/ethnicity was examined. Results- In multivariable analysis, SA was associated with an increased odds of carotid plaque presence in individuals aged <68 years (odds ratio, 1.47; 95% CI, 1.05-2.06) but not in older individuals (odds ratio, 0.95; 95% CI, 0.67-1.37; P interaction=0.078). Greater hypoxemia (sleep time <90% saturation) was associated with increasing carotid intima-media thickness in younger (0.028±0.014 mm) but not in older individuals (-0.001±0.013 mm; P interaction=0.106). Self-reported snoring was not associated with carotid atherosclerosis. In assessing race-specific outcomes, greater hypoxemia was associated with increased carotid intima-media thickness in blacks (0.049±0.017 mm; P interaction=0.033). Conclusions- In this large multiethnic population-based sample, sleep disturbances are associated with subclinical carotid atherosclerosis in both men and women, particularly in those <68 years of age. The mechanisms underlying the association between SA and carotid atherosclerosis may differ for carotid plaque and carotid intima-media thickness.

Carotid artery displacement and cardiovascular disease risk in the Multi-Ethnic Study of Atherosclerosis.

Novel technology permits quantification of common carotid artery (CCA) displacement, which is traditionally ignored. We evaluated associations with CCA displacement and cardiovascular disease (CVD) risk and events in a large, multi-ethnic cohort. Right CCA longitudinal displacement (LD), transverse displacement (TD), and grayscale median (GSM) were evaluated using ultrasound speckle-tracking and texture analysis software in 2050 participants. Regression analyses were used to define relationships between CCA LD, TD, GSM, and CVD risk factors. Cox proportional hazards models were used to assess relationships between LD, TD, and incident CVD events. Participants were mean (SD) 64 (10) years old. There were 791 cases with a CVD event over a 12-year median follow-up. The mean LD was 0.29 (0.20) mm. In multivariable models including age, sex, race/ethnicity, heart rate, and CVD risk factors, LD was associated positively with active smoking (ß = 0.08, p < 0.001) and inversely with black (ß = -0.08, p < 0.001), Chinese (ß = -0.05, p < 0.001), and Hispanic (ß = -0.04, p < 0.05) race/ethnicities relative to white individuals, heart rate (ß = -0.03/10 beats/min, p < 0.001), and diastolic blood pressure (ß = -0.01/5 mmHg, p < 0.05). In fully adjusted models, LD and TD were associated with GSM (p < 0.01), but neither predicted incident CVD events (LD: hazard ratio (HR) 0.77 [0.48 to 1.24], p = 0.3; TD: HR 1.12 [0.8 to 1.57], p = 0.5). CCA LD and TD are associated with race/ethnicity and CVD risk factors but not incident CVD events. LD and TD are not measures of arterial stiffness but their association with GSM suggests that lower LD and TD may be related to structural changes within the carotid arterial wall.

Brachial artery intima-media thickness and grayscale texture changes in patients with peripheral artery disease receiving supervised exercise training in the PROPEL randomized clinical trial.

We performed an exploratory analysis to evaluate the effects of a treadmill exercise program on brachial artery (BA) intima-media thickness (IMT) and three BA grayscale ultrasound measures that may indicate subclinical arterial injury. Data were from a clinical trial in individuals with peripheral artery disease who were randomly assigned to treadmill exercise training or attention control. B-mode ultrasonography was performed at baseline and after 26 weeks. BA IMT, grayscale median (GSM), entropy, and gray-level difference statistic-contrast (GLDS-CON) were measured by a single reader. The 184 participants were (mean (SD)) 66.7 (8.2) years old and had an ankle-brachial index of 0.70 (0.18). Exercise training was associated with a 0.01 (0.06) mm ( p = 0.025) reduction in BA IMT compared to 0.00 (0.05) mm ( p = 0.807) in the control group (between-group p = 0.061). BA GSM, entropy, and GLDS-CON did not change significantly with exercise. Improvements in the 6-minute walk distance correlated with increases in resting BA blood flow ( r = 0.23, p = 0.032), flow-mediated dilation ( r = 0.24, p = 0.022), diameter ( r = 0.29, p = 0.005), entropy ( r = 0.21, p = 0.047), and GLDS-CON ( r = 0.22, p = 0.041). In a post hoc analysis, BA IMT improved significantly with treadmill exercise training but did not change with attention control; however, the between-group difference did not reach statistical significance. With exercise, improvements in the 6-minute walk distance were associated with improved endothelial function, increased resting blood flow, and BA dilation, as well as higher grayscale entropy and GLDS-CON, indicating that lower extremity exercise is associated with salutary changes in upper-extremity arterial wall structure and function. ClinicalTrials.gov Identifier: NCT01408901.

Changes in carotid artery structure with smoking cessation.

Carotid artery grayscale ultrasound echogenicity and texture features predict cardiovascular disease events. We evaluated the longitudinal effects of smoking cessation on four grayscale ultrasound measures. This was a secondary analysis of data from 188 age, sex, and body mass index (BMI)-matched smokers (94 eventual abstainers [EA], 94 continued smokers [CS]) from a smoking cessation trial that had carotid ultrasound examinations at baseline and after 3 years. General linear models that included time, smoking group (EA or CS), and a time*smoking interaction term were used to examine the impact of smoking abstinence on carotid artery grayscale marker values at year 3. Participants were mean (SD) 50.3 (11.4) years old (57% female, 86% white). The baseline grayscale median value (GSM) was inversely correlated with age, BMI, insulin resistance, and smoking pack-years (r = -0.20 to -0.30, p < 0.007 for all). There was a significant time*smoking status interaction for predicting GSM at year 3: GSM decreased significantly in the EA group compared to the CS group (-3.63 [13.00] vs CS 0.39 [12.06] units; p = 0.029). BMI increased more in the EA than the CS group (2.42 [3.00] vs CS 0.35 [2.57] kg/m2; p < 0.001). After adjusting for changes in BMI, the time*smoking status interaction no longer was significant (p = 0.138). From baseline to year 3, contrast increased similarly in both groups. Entropy and angular second moment did not change significantly in either group. Changes in carotid ultrasound echogenicity and grayscale texture features during a smoking cessation attempt are modest and mostly related to weight gain. Clinicaltrials.gov Identifier: NCT01553084.

Influence of Ultrasound System and Gain on Grayscale Median Values.

OBJECTIVES: The purpose of this study was to determine the reliability of grayscale median (GSM) measurements across different ultrasound (US) systems and effects of gain on GSM values. METHODS: Two vessels in a grayscale vascular phantom were imaged with 7 US systems at 3 gain settings. Two human participants were imaged at 3 gain settings. Each image was normalized, standardized, and segmented by expert and novice readers using grayscale analysis software. The concordance correlation coefficient (CCC) assessed agreement of GSM values for each system across gain settings and vessels and between readers. The intraclass correlation coefficient (ICC) assessed system-level reader concordance across gain settings and vessels. A general linear mixed model for repeated measures was used to assess within- and between-system mean GSM values. RESULTS: Grayscale median measurements performed on images from the same US system yielded excellent (CCC) (95% confidence intervals): 0.85 (0.75, 0.92) to 0.96 (0.92, 0.98). ICC per system were 0.94 to 0.98 for the expert reader and 0.85 to 0.95 for the novice reader. Gain adjustments above and below an optimal setting contributed to significantly different intrasystem GSM values on 4 of 7 systems in the near zone and 5 of 7 systems in the far zone (P < .05). Intersystem GSM values differed on 5 of 7 systems (P < .05). Images from the human participants showed differences in GSM values at optimum gain values ± 10 dB/%. CONCLUSIONS: Grayscale median measurements are highly reproducible when obtained from the same US system with similar gain settings. Grayscale median values differ significantly across gain values and between systems. Researchers should consider the impact of US system and gain settings on GSM values when working to minimize system- and operator-dependent factors.

Echogenicity of the carotid arterial wall in active smokers.

This pilot study evaluated associations between carotid wall echogenicity, cardiovascular disease (CVD) risk factors, and three markers of smoking heaviness in a cohort of active smokers. Common carotid artery (CCA) grayscale median (GSM) values were measured from sonographic images. Univariable correlations and exploratory multivariable models were used to determine associations between CCA GSM, CVD risk factors, and measures of smoking heaviness. CCA GSM was measured in 162 smokers and was correlated inversely with cigarettes smoked/day (r=-0.16, p=0.048), pack-years (r=-0.204, p=0.009), CVD risk factors such as age, male sex, waist circumference, and low-density lipoprotein cholesterol (all p≤0.03) and positively with high-density lipoprotein cholesterol (p<0.001). Associations between CCA GSM and smoking heaviness markers were not statistically significant after adjustment for traditional risk factors. The results from this pilot study demonstrate the feasibility of measuring the GSM value of the CCA far wall and its association with measures of smoking heaviness and traditional CVD risk factors among current smokers.

Sex differences in predictors of longitudinal changes in carotid artery stiffness: the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE: To identify sex differences in predictors of longitudinal changes in carotid arterial stiffness in a multiethnic cohort. APPROACH AND RESULTS: Carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM) were measured in 2650 Multi-Ethnic Study of Atherosclerosis participants (45-84 years old and free of cardiovascular disease) at baseline and after a mean of 9.4 years. Predictors of changes in DC and YEM for each sex were evaluated using multivariable linear regression models. The 1236 men (46.6%) were 60.0 (SD, 9.3) years: 40% were white, 22% black, 16% Chinese, and 22% Hispanic. The 1414 (53.4%) women were 59.8 (9.4) years old with a similar race distribution. Despite similar rates of change in DC and YEM, predictors of changes in distensibility markers differed by sex. In men, Chinese (P=0.002) and black (P=0.003) race/ethnicity, systolic blood pressure (P=0.012), and diabetes mellitus (P=0.05) were associated with more rapidly decreasing DC (accelerated stiffening). Starting antihypertensive medication was associated with improved DC (P=0.03); stopping antihypertensives was associated with more rapid stiffening (increased YEM, P=0.05). In women, higher education was associated with slower stiffening (DC, P=0.041; YEM, P<0.001) as was use of lipid-lowering medication (P=0.03), whereas baseline use of antihypertensive medications (YEM, P=0.01) and systolic blood pressure (DC, P=0.02; P=0.04) predicted increasing stiffening in women. CONCLUSIONS: Longitudinal changes in carotid artery stiffness are associated with systolic blood pressure and antihypertensive therapy in both sexes; however, race/ethnicity (in men) and level of education (in women) may have different contributions between the sexes.

Asthma predicts cardiovascular disease events: the multi-ethnic study of atherosclerosis.

OBJECTIVES: To identify and characterize an association between persistent asthma and cardiovascular disease (CVD) risk in the Multi-Ethnic Study of Atherosclerosis (MESA). APPROACH AND RESULTS: MESA is a longitudinal prospective study of an ethnically diverse cohort of individuals free of known CVD at its inception. The presence and severity of asthma were assessed in the MESA at examination 1. Persistent asthma was defined as asthmatics using controller medications (inhaled corticosteroids, leukotriene inhibitors, and oral corticosteroids) and intermittent asthma as asthmatics not using controller medications. Participants were followed up for a mean (SD) of 9.1 (2.8) years for development of incident CVD (coronary death, myocardial infarction, angina, stroke, and CVD death). Multivariable Cox regression models were used to assess associations of asthma and CVD. The 6792 participants were 62.2 (SD, 10.2) years old: 47% men (28% black, 22% Hispanic, and 12% Chinese). Persistent asthmatics (n=156), compared with intermittent (n=511) and nonasthmatics (n=6125), respectively, had higher C-reactive protein (1.2 [1.2] versus 0.9 [1.2] versus 0.6 [1.2] mg/L) and fibrinogen (379 [88] versus 356 [80] versus 345 [73] mg/dL) levels. Persistent asthmatics had the lowest unadjusted CVD-free survival rate of 84.1%, 95% confidence interval (78.9%-90.3%) compared with intermittent asthmatics 91.1% (88.5%-93.8%) and nonasthmatics 90.2% (89.4%-91%). Persistent asthmatics had greater risk of CVD events than nonasthmatics (hazard ratio [95% confidence interval], 1.6 [1.01-2.5]; P=0.040]), even after adjustment for age, sex, race, CVD risk factors, and antihypertensive and lipid medication use. CONCLUSIONS: In this large multiethnic cohort, persistent asthmatics had a higher CVD event rate than nonasthmatics.

Relationships between sleep apnea, cardiovascular disease risk factors, and aortic pulse wave velocity over 18 years: the Wisconsin Sleep Cohort.

PURPOSE: The purpose of this study is to determine if apnea-hypopnea index (AHI) severity predicts future aortic pulse wave velocity (PWV) in the Wisconsin Sleep Cohort. METHODS: Applanation tonometry was used to derive carotid-to-femoral PWV a mean of 18 years (standard deviation 4) after overnight polysomnography. Multivariable regression models were created to describe prospective associations between baseline AHI and future PWV. RESULTS: The 618 adults were mean 65 (7) years old (55 % male) with a mean body mass index of 31 (7) kg/m(2) at the tonometry visit. Mean baseline AHI was 4.6 (9.7) events/h. In multiple linear regression models adjusted for age (ß = 0.13/year, standard error [SE] = 0.01, p < 0.001) and sex, higher log10AHI (ß = 0.43/events/h, SE = 0.18, p = 0.02) was associated with PWV. After adjustment for waist circumference (ß = 0.01/cm, SE = 0.01, p = 0.05) and height, the association between baseline log10AHI and future PWV was not statistically significant (p = 0.11), although the association with age persisted unchanged. Addition of covariates such as smoking status (current smoker ß = 0.66, SE = 0.22, p = 0.002), diabetes mellitus status (ß = 2.89, SE = 0.59, p < 0.001), and systolic blood pressure (BP, ß = 0.03/mmHg, SE = 0.01, p < 0.001) did not change the association. AHI did not interact with age or smoking status to predict PWV. A secondary analysis of nocturnal oxygen saturation parameters in 517 participants, 9 (2) years prior also did not show any significant relationships with future PWV. CONCLUSIONS: The prospective association between AHI and PWV is confounded by body size and influenced by smoking, diabetes mellitus, and BP. Weight management, BP control, and smoking cessation may help prevent arterial stiffening associated with obstructive sleep apnea.

Minimal nocturnal oxygen saturation predicts future subclinical carotid atherosclerosis: the Wisconsin sleep cohort.

Previous data on the associations between nocturnal oxygen saturation parameters and carotid atherosclerosis are conflicting. We examined the prospective associations of nocturnal oxygen saturation (SaO2 ) and cardiovascular disease (CVD) risk factors with carotid intima-media thickness (IMT) and plaques. We used data on 689 Wisconsin sleep cohort participants who had baseline overnight polysomnography followed by carotid ultrasonography a mean (SD) of 7.8 (2.5) years later. Far wall common carotid IMT was measured using B-mode ultrasound. Bilateral common, bifurcation and internal carotid artery segments were evaluated for plaque score. Participants (8) were aged 56 years (55% male); 32% had hypertension and mean body mass index (BMI) was 31 (7) kg m(2). Mean and minimum nocturnal SaO2 were 95% (2) and 86% (7), respectively. Mean percentage sleep time with SaO2 < 90% was 2% (8). Both mean (odds ratio [OR]: 0.60 lower plaque count per 5% higher mean SaO2, 95% confidence interval [CI]: 0.38-0.96, P = 0.033) and minimum SaO2 (OR: 0.88 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.80-0.97, P = 0.013) predicted carotid plaque score after adjusting for age, sex and BMI. Minimum SaO2 predicted future plaque score after adding adjustment for traditional CVD risk factors (OR: 0.90 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.81-0.99, P = 0.038). Mean SaO2 was not associated with carotid IMT after CVD risk factor adjustment. We conclude that minimum nocturnal SaO2 is an independent predictor of future carotid plaque burden. Other nocturnal SaO2 parameters are not associated with future carotid IMT or plaques after adjusting for traditional CVD risk factors.

Obstructive sleep apnea is associated with future subclinical carotid artery disease: thirteen-year follow-up from the Wisconsin sleep cohort.

OBJECTIVE: To determine the longitudinal associations between obstructive sleep apnea, carotid artery intima-media thickness (IMT), and plaque. APPROACH AND RESULTS: This is a population-based, prospective cohort study conducted from July, 1989, to November, 2012, on 790 randomly selected Wisconsin residents who completed a mean of 3.5 (range, 1-6) polysomnograms during the study period. Obstructive sleep apnea was characterized by the apnea-hypopnea index (AHI, events/h). Common carotid artery IMT and plaque were assessed by B-mode ultrasound. The mean (SD) time from the first polysomnograms to carotid ultrasound was 13.5 (3.6) years. Multivariable regression models were created to estimate the independent associations of baseline and cumulative obstructive sleep apnea exposure with subsequent carotid IMT and plaque. At baseline, the mean age of participants was 47.6 (7.7) years (55% men, 97% white). AHI was 4.4 (9.0) events/h (range, 0-97); 7% had AHI >15 events/h. Carotid IMT was 0.755 (0.161) mm; 63% had plaque. Adjusting for age, sex, body mass index, systolic blood pressure, smoking, and use of lipid-lowering, antihypertensive, and antidiabetic medications, baseline AHI independently predicted future carotid IMT (ß=0.027 mm/unit log10[AHI+1]; P=0.049), plaque presence (odds ratio, 1.55 [95% confidence intervals, 1.02-2.35]; P=0.041) and plaque score (odds ratio, 1.30 [1.05-1.61]; P=0.018). In cumulative risk factor-adjusted models, AHI independently predicted future carotid plaque presence (P=0.012) and score (P=0.039), but not IMT (P=0.608). CONCLUSIONS: Prevalent obstructive sleep apnea is independently associated with increased carotid IMT and plaque more than a decade later, indicating increased future cardiovascular disease risk.

25-hydroxyvitamin D and parathyroid hormone levels do not predict changes in carotid arterial stiffness: the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE: To evaluate the impact of vitamin D and parathyroid hormone (PTH) on longitudinal changes in arterial stiffness. APPROACH AND RESULTS: Distensibility coefficient and Young's elastic modulus of the right common carotid artery were evaluated at baseline and after a mean (SD) of 9.4 (0.5) years in 2580 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Cross-sectional and longitudinal associations were evaluated using multivariable linear regression and analysis of covariance. At baseline, participants were 60.1 (9.4) years old (54% female; 26% black, 20% Hispanic, 14% Chinese). Mean annualized 25(OH)D was <20 ng/dL in 816 participants, and PTH was >65 pg/dL in 285 participants. In cross-sectional analyses, low 25(OH)D (<20 ng/mL) was not associated with stiffer arteries after adjustment for cardiovascular disease risk factors (P>0.4). PTH >65 pg/mL was associated with stiffer arteries after adjustment for cardiovascular disease risk factors, other than systolic blood pressure (distensibility coefficient: ß=-2.4×10(-4) mm Hg(-1), P=0.003; Young's elastic modulus: ß=166 mm Hg, P=0.01); however, after adjustment for systolic blood pressure, these associations no longer were statistically significant. Longitudinal arterial stiffening was associated with older age (P<0.0001), higher systolic blood pressure (P<0.008), and use of antihypertensive medications (P<0.006), but not with 25(OH)D or PTH (both P>0.1). CONCLUSIONS: Carotid arterial stiffness is not associated with low 25(OH)D concentrations. Cross-sectional associations between arterial stiffness and high PTH were attenuated by systolic blood pressure. After nearly a decade of follow-up, neither baseline PTH nor 25(OH)D concentrations were associated with progression of carotid arterial stiffness.

Cardiorespiratory Fitness Attenuates the Influence of Amyloid on Cognition.

The aim of this study was to examine cross-sectionally whether higher cardiorespiratory fitness (CRF) might favorably modify amyloid-ß (Aß)-related decrements in cognition in a cohort of late-middle-aged adults at risk for Alzheimer's disease (AD). Sixty-nine enrollees in the Wisconsin Registry for Alzheimer's Prevention participated in this study. They completed a comprehensive neuropsychological exam, underwent 11C Pittsburgh Compound B (PiB)-PET imaging, and performed a graded treadmill exercise test to volitional exhaustion. Peak oxygen consumption (VO2peak) during the exercise test was used as the index of CRF. Forty-five participants also underwent lumbar puncture for collection of cerebrospinal fluid (CSF) samples, from which Aß42 was immunoassayed. Covariate-adjusted regression analyses were used to test whether the association between Aß and cognition was modified by CRF. There were significant VO2peak*PiB-PET interactions for Immediate Memory (p=.041) and Verbal Learning & Memory (p=.025). There were also significant VO2peak*CSF Aß42 interactions for Immediate Memory (p<.001) and Verbal Learning & Memory (p<.001). Specifically, in the context of high Aß burden, that is, increased PiB-PET binding or reduced CSF Aß42, individuals with higher CRF exhibited significantly better cognition compared with individuals with lower CRF. In a late-middle-aged, at-risk cohort, higher CRF is associated with a diminution of Aß-related effects on cognition. These findings suggest that exercise might play an important role in the prevention of AD.

Occupational characteristics and the progression of carotid artery intima-media thickness and plaque over 9†years: the Multi-Ethnic Study of Atherosclerosis (MESA).

OBJECTIVES: The role of occupation in the development of cardiovascular disease (CVD) remains a topic of research because few studies have examined longitudinal associations, and because occupation can be an indicator of socioeconomic position (SEP) and a proxy for hazard exposure. This study examines associations of occupational category as an SEP marker and selected occupational exposures with progression of the subclinical carotid artery disease. METHODS: A community-based, multiethnic sample (n=3109, mean age=60.2) provided subclinical CVD measures at least twice at three data collection points (mean follow-up=9.4 years). After accounting for demographic characteristics, SEP, and traditional CVD risk factors, we modelled common carotid intima-media thickness, carotid plaque scores, and carotid plaque shadowing as a function of occupational category, physical hazard exposure, physical activity on the job, interpersonal stress, job control and job demands. These job characteristics were derived from the Occupational Resource Network (O*NET). Random coefficient models were used to account for repeated measures and time-varying covariates. RESULTS: There were a few statistically significant associations at baseline. After all covariates were included in the model, men in management, office/sales, service and blue-collar jobs had 28-44% higher plaque scores than professionals at baseline (p=0.001). Physically hazardous jobs were positively associated with plaque scores among women (p=0.014). However, there were no significant longitudinal associations between any of the occupational characteristics and any of the subclinical CVD measures. CONCLUSIONS: There was little evidence that the occupational characteristics examined in this study accelerated the progression of subclinical CVD.

Longitudinal effects of a decade of aging on carotid artery stiffness: the multiethnic study of atherosclerosis.

BACKGROUND AND PURPOSE: Arterial stiffening is associated with hypertension, stroke, and cognitive decline; however, the effects of aging and cardiovascular disease risk factors on carotid artery stiffening have not been assessed prospectively in a large multiethnic longitudinal study. METHODS: Distensibility coefficient and the Young's elastic modulus (YEM) of the right common carotid artery were calculated at baseline and after a mean of 9.4 (standard deviation [SD], 0.5) years in 2650 participants. Effects of age and cardiovascular disease risk factors were evaluated by multivariable mixed regression and ANCOVA models. RESULTS: At baseline, participants were 59.9 (SD, 9.4) years old (53% women; 25% black, 22% Hispanic, 14% Chinese). YEM increased from 1581 (SD, 927) to 1749 (SD, 1306) mm Hg (P<0.0001), and distensibility coefficient decreased from 3.1 (SD, 1.3) to 2.7 (SD, 1.1)×10(-3) mm Hg(-1) (P<0.001), indicating progressive arterial stiffening. YEM increased more among participants who were aged>75 years old at baseline (P<0.0001). In multivariable analyses, older age and less education independently predicted worsening YEM and distensibility coefficient. Stopping antihypertensive medication during the study period predicted more severe worsening of YEM (ß=360.2 mm Hg; P=0.008). Starting antihypertensive medication after examination 1 was predictive of improvements in distensibility coefficient (ß=1.1×10(-4) mm Hg(-1); P=0.024). CONCLUSIONS: Arterial stiffening accelerates with advanced age. Older individuals experience greater increases in YEM than do younger adults, even after considering the effects of traditional risk factors. Treating hypertension may slow the progressive decline in carotid artery distensibility observed with aging and improve cerebrovascular health.

Predictors of carotid thickness and plaque progression during a decade: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND PURPOSE: Carotid artery intima-media thickness (IMT) and plaque are noninvasive markers of subclinical arterial injury that predict incident cardiovascular disease. We evaluated predictors of longitudinal changes in IMT and new plaque during a decade in a longitudinal multiethnic cohort. METHODS: Carotid IMT and plaque were evaluated in Multi-Ethnic Study of Atherosclerosis (MESA) participants at exams 1 and 5, a mean (standard deviation) of 9.4 (0.5) years later. Far wall carotid IMT was measured in both common and internal carotid arteries. A plaque score was calculated from all carotid segments. Mixed-effects longitudinal and multivariate regression models evaluated associations of baseline risk factors and time-updated medication use with IMT progression and plaque formation. RESULTS: The 3441 MESA participants were aged 60.3 (9.4) years (53% women; 26% blacks, 22% Hispanic, 13% Chinese); 1620 (47%) had carotid plaque. Mean common carotid artery IMT progression was 11.8 (12.8) µm/year, and 1923 (56%) subjects developed new plaque. IMT progressed more slowly in Chinese (ß=-2.89; P=0.001) and Hispanic participants (ß=-1.81; P=0.02), and with higher baseline high-density lipoprotein cholesterol (per 5 mg/dL; ß=-0.22; P=0.03), antihypertensive use (ß=-2.06; P=0.0004), and time on antihypertensive medications (years; ß=-0.29; P<0.0001). Traditional risk factors were associated with new plaque formation, with strong associations for cigarette use (odds ratio, 2.31; P<0.0001) and protection by black ethnicity (odds ratio, 0.68; P<0.0001). CONCLUSIONS: In a large, multiethnic cohort with a decade of follow-up, ethnicity was a strong, independent predictor of carotid IMT and plaque progression. Antihypertensive medication use was associated with less subclinical disease progression.