Associations of recreational and non-recreational physical activity with coronary artery calcium density vs. volume and cardiovascular disease events: the Multi-Ethnic Study of Atherosclerosis.

AIMS: The benefits of physical activity (PA) on cardiovascular disease (CVD) are well known. However, studies suggest PA is associated with coronary artery calcium (CAC), a subclinical marker of CVD. In this study, we evaluated the associations of self-reported recreational and non-recreational PA with CAC composition and incident CVD events. Prior studies suggest high CAC density may be protective for CVD events. METHODS AND RESULTS: We evaluated 3393 participants of the Multi-Ethnic Study of Atherosclerosis with prevalent CAC. After adjusting for demographics, the highest quintile of recreational PA was associated with 0.07 (95% confidence interval 0.01-0.13) units greater CAC density but was not associated with CAC volume. In contrast, the highest quintile of non-recreational PA was associated with 0.08 (0.02-0.14) units lower CAC density and a trend toward 0.13 (-0.01 to 0.27) log-units higher CAC volume. There were 520 CVD events over a 13.7-year median follow-up. Recreational PA was associated with lower CVD risk (hazard ratio 0.88, 0.79-0.98, per standard deviation), with an effect size that was not changed with adjustment for CAC composition or across levels of prevalent CAC. CONCLUSION: Recreational PA may be associated with a higher density but not a higher volume of CAC. Non-recreational PA may be associated with lower CAC density, suggesting these forms of PA may not have equivalent associations with this subclinical marker of CVD. While PA may affect the composition of CAC, the associations of PA with CVD risk appear to be independent of CAC.

Thoracic Aorta Calcification and Noncardiovascular Disease-Related Mortality.

Objective- Arterial calcification is highly correlated with underlying atherosclerosis. Arterial calcification of the thoracic aorta is evident in many older individuals at high susceptibility to aging-related diseases and non-cardiovascular disease (CVD)-related mortality. In this study, we evaluated the association of thoracic aorta calcification (TAC) with non-CVD morbidity and mortality. Approach and Results- We analyzed data from participants in the Multi-Ethnic Study of Atherosclerosis, a prospective cohort study of subclinical atherosclerosis, in which participants underwent cardiac computed tomography at baseline and were followed longitudinally for incident CVD events and non-CVD events. Using modified proportional hazards models accounting for the competing risk of CVD death and controlling for demographics, CVD risk factors, coronary artery calcium, and CVD events, we evaluated whether TAC was independently associated with non-CVD morbidity and mortality. Among 6765 participants (mean age, 62 years), 704 non-CVD deaths occurred for a median follow-up of 12.2 years. Compared with no TAC, the highest tertile of TAC volume was associated with a higher risk of non-CVD mortality (hazard ratio, 1.56; 95% confidence interval, 1.23-1.97), as well as several non-CVD diagnoses, including hip fracture (2.14; 1.03-4.46), chronic obstructive pulmonary disease (2.06; 1.29-3.29), and pneumonia (1.79; 1.30-2.45), with magnitudes of association that were larger than for those of coronary artery calcium. Conclusions- TAC is associated with non-CVD morbidity and non-CVD mortality, potentially through a pathway that is unrelated to atherosclerosis. TAC may be a general marker of biological aging and an indicator of increased risk of non-CVD and death.

Progression of calcium density in the ascending thoracic aorta is inversely associated with incident cardiovascular disease events.

Aims: Little is known regarding the risk of atherosclerotic cardiovascular disease (ASCVD) conferred by changes in the volume and density of ascending thoracic aorta calcium (ATAC) over time. We evaluated changes in ATAC volume and density scores and incident ASCVD events. Methods and results: The Multi-Ethnic Study of Atherosclerosis is a prospective cohort study of individuals without baseline clinical ASCVD. Ascending thoracic aorta calcium was measured from baseline and follow-up (mean interval 2.4 years) cardiac computed tomography (CT). Cox proportional hazard regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) per standard deviation for events after the follow-up exam adjusted for ASCVD risk factors, baseline ATAC and coronary artery calcium (CAC) volume and density, and changes in CAC volume and density. Among 5887 participants, 296 (5.0%) had detectable ATAC at baseline, follow-up, or both exams. A total of 403 events occurred over 9.5 years. An increase in ATAC volume was associated with coronary heart disease (CHD) (HR 1.90, 95% CI 1.14-3.16), ASCVD (HR 1.93, 95% CI 1.26-2.94), and ischaemic stroke (HR 2.14, CI 1.21-3.78). An increase in ATAC density was inversely associated with CHD (HR 0.29, 95% CI 0.14-0.60) and ASCVD (HR 0.42, 95% CI 0.23-0.76), but not stroke (HR 0.61, CI 0.23-1.61). Conclusion: Ascending thoracic aorta calcium is uncommon on serial cardiac CT. However, changes in ATAC volume and density are both associated with incident ASCVD events, but in opposite directions. Serial assessments in those with baseline ATAC may provide insight into an individual's trajectory of ASCVD risk.

The evolving view of coronary artery calcium and cardiovascular disease risk.

Calcification of the coronary artery is a complex pathophysiologic process that is intimately associated with atherosclerosis. Extensive investigation has demonstrated the value of identifying and quantifying coronary artery calcium (CAC) in atherosclerotic cardiovascular disease (CVD) prognostication. However, over the last several years, an increasing body of evidence has suggested that CAC has underappreciated aspects that modulate, and at times attenuate, future CVD risk. The most commonly used measure of CAC, the Agatston unit, effectively models both higher density and higher area of CAC as risk factors for future CVD events. Recent findings from the Multi-Ethnic Study of Atherosclerosis (MESA) have challenged this assumption, demonstrating that higher density of CAC is protective for coronary heart disease and CVD events. Statins may be associated with an increase in CAC, an unexpected finding given their clear benefits in the prevention and treatment of CVD. Studies utilizing intracoronary ultrasound and coronary computed tomography angiography have demonstrated that calcified atherosclerotic plaque-as compared with noncalcified or sparsely calcified plaque-is associated with fewer CVD events. These studies lend support to the often-asserted (but as yet unvalidated) view that calcification may play a role in plaque stabilization. Furthermore, vascular calcification, though a surrogate for atherosclerotic plaque burden, may also possess identifiable aspects that can refine CVD risk assessment.

Association of cardiovascular disease risk factors with coronary artery calcium volume versus density.

OBJECTIVES: Recently, the density score of coronary artery calcium (CAC) has been shown to be associated with a lower risk of cardiovascular disease (CVD) events at any level of CAC volume. Whether risk factors for CAC volume and CAC density are similar or distinct is unknown. We sought to evaluate the associations of CVD risk factors with CAC volume and CAC density scores. METHODS: Baseline measurements from 6814 participants free of clinical CVD were collected for the Multi-Ethnic Study of Atherosclerosis. Participants with detectable CAC (n=3398) were evaluated for this study. Multivariable linear regression models were used to evaluate independent associations of CVD risk factors with CAC volume and CAC density scores. RESULTS: Whereas most CVD risk factors were associated with higher CAC volume scores, many risk factors were associated with lower CAC density scores. For example, diabetes was associated with a higher natural logarithm (ln) transformed CAC volume score (standardised ß=0.44 (95% CI 0.31 to 0.58) ln-units) but a lower CAC density score (ß=-0.07 (-0.12 to -0.02) density units). Chinese, African-American and Hispanic race/ethnicity were each associated with lower ln CAC volume scores (ß=-0.62 (-0.83to -0.41), -0.52 (-0.64 to -0.39) and -0.40 (-0.55 to -0.26) ln-units, respectively) and higher CAC density scores (ß= 0.41 (0.34 to 0.47), 0.18 (0.12 to 0.23) and 0.21 (0.15 to 0.26) density units, respectively) relative to non-Hispanic White. CONCLUSIONS: In a cohort free of clinical CVD, CVD risk factors are differentially associated with CAC volume and density scores, with many CVD risk factors inversely associated with the CAC density score after controlling for the CAC volume score. These findings suggest complex associations between CVD risk factors and these components of CAC.

Density of calcium in the ascending thoracic aorta and risk of incident cardiovascular disease events.

BACKGROUND AND AIMS: The volume and density of coronary artery calcium (CAC) both independently predict cardiovascular disease (CVD) beyond standard risk factors, with CAC density inversely associated with incident CVD after accounting for CAC volume. We tested the hypothesis that ascending thoracic aorta calcium (ATAC) volume and density predict incident CVD events independently of CAC. METHODS: The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective cohort study of participants without clinical CVD at baseline. ATAC and CAC were measured from baseline cardiac computed tomography (CT). Cox regression models were used to estimate the associations of ATAC volume and density with incident coronary heart disease (CHD) events and CVD events, after adjustment for standard CVD risk factors and CAC volume and density. RESULTS: Among 6811 participants, 234 (3.4%) had prevalent ATAC and 3395 (49.8%) had prevalent CAC. Over 10.3 years, 355 CHD and 562 CVD events occurred. One-standard deviation higher ATAC density was associated with a lower risk of CHD (HR 0.48 [95% CI 0.29-0.79], p<0.01) and CVD (HR 0.56 [0.37-0.84], p<0.01) after full adjustment. ATAC volume was not associated with outcomes after full adjustment. CONCLUSIONS: ATAC was uncommon in a cohort free of clinical CVD at baseline. However, ATAC density was inversely associated with incident CHD and CVD after adjustment for CVD risk factors and CAC volume and density.

Coronary Artery Calcium Volume and Density: Potential Interactions and Overall Predictive Value: The Multi-Ethnic Study of Atherosclerosis.

OBJECTIVES: This study sought to determine the possibility of interactions between coronary artery calcium (CAC) volume or CAC density with each other, and with age, sex, ethnicity, the new atherosclerotic cardiovascular disease (ASCVD) risk score, diabetes status, and renal function by estimated glomerular filtration rate, and, using differing CAC scores, to determine the improvement over the ASCVD risk score in risk prediction and reclassification. BACKGROUND: In MESA (Multi-Ethnic Study of Atherosclerosis), CAC volume was positively and CAC density inversely associated with cardiovascular disease (CVD) events. METHODS: A total of 3,398 MESA participants free of clinical CVD but with prevalent CAC at baseline were followed for incident CVD events. RESULTS: During a median 11.0 years of follow-up, there were 390 CVD events, 264 of which were coronary heart disease (CHD). With each SD increase of ln CAC volume (1.62), risk of CHD increased 73% (p < 0.001) and risk of CVD increased 61% (p < 0.001). Conversely, each SD increase of CAC density (0.69) was associated with 28% lower risk of CHD (p < 0.001) and 25% lower risk of CVD (p < 0.001). CAC density was inversely associated with risk at all levels of CAC volume (i.e., no interaction was present). In multivariable Cox models, significant interactions were present for CAC volume with age and ASCVD risk score for both CHD and CVD, and CAC density with ASCVD risk score for CVD. Hazard ratios were generally stronger in the lower risk groups. Receiver-operating characteristic area under the curve and Net Reclassification Index analyses showed better prediction by CAC volume than by Agatston, and the addition of CAC density to CAC volume further significantly improved prediction. CONCLUSIONS: The inverse association between CAC density and incident CHD and CVD events is robust across strata of other CVD risk factors. Added to the ASCVD risk score, CAC volume and density provided the strongest prediction for CHD and CVD events, and the highest correct reclassification.

Femoral Artery Atherosclerosis Is Associated With Physical Function Across the Spectrum of the Ankle-Brachial Index: The San Diego Population Study.

BACKGROUND: The ankle-brachial index (ABI) is inadequate to detect early-stage atherosclerotic disease, when interventions to prevent functional decline may be the most effective. We determined associations of femoral artery atherosclerosis with physical functioning, across the spectrum of the ABI, and within the normal ABI range. METHODS AND RESULTS: In 2007-2011, 1103 multiethnic men and women participated in the San Diego Population Study, and completed all components of the summary performance score. Using Doppler ultrasound, superficial and common femoral intima media thickness and plaques were ascertained. Logistic regression was used to assess associations of femoral atherosclerosis with the summary performance score and its individual components. Models were adjusted for demographics, lifestyle factors, comorbidities, lipids, and kidney function. In adjusted models, among participants with a normal-range ABI (1.00-1.30), the highest tertile of superficial intima media thickness was associated with lower odds of a perfect summary performance score of 12 (odds ratio=0.56 [0.36, 0.87], P=0.009), and lower odds of a 4-m walk score of 4 (0.34 [0.16, 0.73], P=0.006) and chair rise score of 4 (0.56 [0.34, 0.94], P=0.03). Plaque presence (0.53 [0.29, 0.99], P=0.04) and greater total plaque burden (0.61 [0.43, 0.87], P=0.006) were associated with worse 4-m walk performance in the normal-range ABI group. Higher superficial intima media thickness was associated with lower summary performance score in all individuals (P=0.02). CONCLUSIONS: Findings suggest that use of femoral artery atherosclerosis measures may be effective in individuals with a normal-range ABI, especially, for example, those with diabetes mellitus or a family history of peripheral artery disease, when detection can lead to earlier intervention to prevent functional declines and improve quality of life.

Race/ethnic and sex disparities in the non-alcoholic fatty liver disease-abdominal aortic calcification association: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: This study investigated the associations of non-alcoholic fatty liver disease (NAFLD) and abdominal aortic calcification (AAC) volume and density, and whether these relationships vary by race/ethnicity and/or sex, information that are limited in current literature. METHODS: We studied 1004 adults from the Multi-Ethnic Study of Atherosclerosis to assess the relationship between NAFLD (liver-to-spleen ratio <1) and the following measures of AAC: presence (volume score >0, using Poisson regression); change in volume score (increasing vs. no change, using Poisson regression); and morphology (volume and density score, where volume score >0, using linear regression); and interaction by race/ethnicity and sex. RESULTS: Among Blacks, those with NAFLD had greater prevalence for AAC compared to Whites regardless of sex (Prevalence Ratio [PR] = 1.41, CI = 1.15-1.74, p-interaction = 0.02). Concurrent interaction by race/ethnicity and sex was found comparing Chinese and Blacks to Whites (p-interaction = 0.017 and 0.042, respectively) in the association between NAFLD and the prevalence of increasing AAC. Among women, this relationship was inverse among Chinese (PR = 0.59, CI = 0.28-1.27), and positive among Whites (PR = 1.34, CI = 1.02-1.76). This finding was reversed evaluating the men counterpart. Black men also had a positive association (PR = 1.86, CI = 1.29-2.70), which differed from the inverse relationship among White men, and was greater compared to Black women (PR = 1.45, CI = 1.09-1.94). NAFLD was unrelated to AAC morphology. CONCLUSIONS: NAFLD was related to the presence of AAC, however, limited to Blacks. Significant concurrent interaction by race/ethnicity (Chinese and Blacks vs. Whites) and sex was found in the relationship between NAFLD and increasing AAC. These findings suggest disparities in the pathophysiologic pathways in which atherosclerosis develops.

Greater Volume but not Higher Density of Abdominal Aortic Calcium Is Associated With Increased Cardiovascular Disease Risk: MESA (Multi-Ethnic Study of Atherosclerosis).

BACKGROUND: Abdominal aortic calcium (AAC) and coronary artery calcium (CAC) independently and similarly predict cardiovascular disease (CVD) events. The standard AAC and CAC score, the Agatston method, upweights for greater calcium density, thereby modeling higher calcium density as a CVD hazard. METHODS AND RESULTS: Computed tomography scans were used to measure AAC and CAC volume and density in a multiethnic cohort of community-dwelling individuals, and Cox proportional hazard was used to determine their independent association with incident coronary heart disease (CHD, defined as myocardial infarction, resuscitated cardiac arrest, or CHD death), cardiovascular disease (CVD, defined as CHD plus stroke and stroke death), and all-cause mortality. In 997 participants with Agatston AAC and CAC scores >0, the mean age was 66±9 years, and 58% were men. During an average follow-up of 9 years, there were 77 CHD, 118 CVD, and 169 all-cause mortality events. In mutually adjusted models, additionally adjusted for CVD risk factors, an increase in ln(AAC volume) per standard deviation was significantly associated with increased all-cause mortality (hazard ratio=1.20; 95% confidence interval, 1.08-1.33; P<0.01) and an increased ln(CAC volume) per standard deviation was significantly associated with CHD (hazard ratio=1.17; 95% confidence interval, 1.04-1.59; P=0.02) and CVD (hazard ratio=1.20; 95% confidence interval, 1.05-1.36; P<0.01). In contrast, both AAC and CAC density were not significantly associated with CVD events. CONCLUSIONS: The Agatston method of upweighting calcium scores for greater density may be inappropriate for CVD risk prediction in both the abdominal aorta and coronary arteries.

Associations of cardiovascular disease risk factors with abdominal aortic calcium volume and density: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND AND AIMS: Abdominal aortic calcium (AAC) predicts future cardiovascular disease (CVD) events and all-cause mortality independent of CVD risk factors. The standard AAC score, the Agatston, up-weights for greater calcium density, and thus models higher calcium density as associated with increased CVD risk. We determined associations of CVD risk factors with AAC volume and density (separately). METHODS: In a multi-ethnic cohort of community living adults, we used abdominal computed tomography scans to measure AAC volume and density. Multivariable linear regression was used to determine the period cross-sectional independent associations of CVD risk factors with AAC volume and AAC density in participants with prevalent AAC. RESULTS: Among 1413 participants with non-zero AAC scores, the mean age was 65 ± 9 years, 52% were men, 44% were European-, 24% were Hispanic-, 18% were African-, and 14% were Chinese Americans (EA, HA, AA, and CA respectively). Median (interquartile range, IQR) for AAC volume was 628 mm3 (157-1939 mm3), and mean AAC density was 3.0 ± 0.6. Compared to EA, each of HA, AA, and CA had lower natural log (ln) AAC volume, but higher AAC density. After adjustments for AAC density, older age, ever smoking history, higher systolic blood pressure, elevated total cholesterol, reduced HDL cholesterol, statin and anti-hypertensive medication use, family history of myocardial infarction, and alcohol consumption were significantly associated with higher ln(AAC volume). In contrast, after adjustments for ln(AAC volume), older age, ever smoking history, higher BMI, and lower HDL cholesterol were significantly associated with lower AAC density. CONCLUSIONS: Several CVD risk factors were associated with higher AAC volume, but lower AAC density. Future studies should investigate the impact of calcium density of aortic plaques in CVD.

Ankle-brachial index predicts change over time in functional status in the San Diego Population Study.

BACKGROUND: Peripheral artery disease (PAD) affects millions of people, both in the U.S. and worldwide. Even when asymptomatic, PAD and the ankle-brachial index (ABI), the major clinical diagnostic criterion for PAD, are associated with decreased functional status and quality of life, as well as mobility impairment. Whether the ABI or change in the ABI predicts decline in functional status over time has not been previously assessed in a population-based setting. METHODS: Participants were 812 non-Hispanic white, African American, Hispanic, and Asian men and women from the San Diego Population Study (SDPS) who attended a baseline examination (1994-1998), and follow-up clinic examination approximately 11 years later. The Medical Outcomes Study 36-Item Short Form (SF-36) was obtained at both the baseline and follow-up examinations, and the summary performance score (SPS) at the follow-up examination. Associations of the baseline ABI and clinically relevant change in the ABI (<-0.15 vs ≥-0.15) with change in SF-36 scores over time were assessed using growth curve models, a type of mixed model that accounts for within participant correlation of measurements over time, and using linear regression for SPS. Models were adjusted for baseline age, sex, race/ethnicity, body mass index, ever smoking, physical activity, hypertension, diabetes, and dyslipidemia. RESULTS: Mean ± standard deviation (SD) for the baseline ABI was 1.11 ± 0.10, and 50.8 ± 9.0 for the baseline Physical Component Score (PCS), 50.1 ± 9.5 for the baseline Mental Component Score (MCS), and 11.2 ± 1.9 for the SPS at the follow-up examination. In fully adjusted models, each SD lower of the baseline ABI was significantly associated with an average decrease over time of 0.6 (95% confidence interval [CI], -1.1 to -0.1; P = .02) units on SF-36 PCS. Each SD lower of the baseline ABI was also significantly associated with an average decrease over time of 1.2 units (95% CI, -2.3 to -0.2; P = .02) on the SF-36 physical functioning subscale, and a decrease of 1.3 units (95% CI, -2.3 to -0.3; P = .01) on the SF-36 energy/vitality subscale in fully adjusted models. Baseline ABI was not significantly associated with change in the SF-36 MCS over time, or the SPS at the follow-up examination. Change in the ABI was not associated with SF-36 PCS, MCS, or the SPS. CONCLUSIONS: In this multiethnic population of healthy middle-aged community-living men and women, we showed that participants with a lower baseline ABI had declines in functional status over 11 years. Findings suggest that small differences in the ABI, even within the normal range, may identify subclinical lower extremity PAD, which in turn may help to identify individuals at risk for declining functional status with age.

Sex and ethnic differences in the associations between lipoprotein(a) and peripheral arterial disease in the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE: Higher lipoprotein(a) [Lp(a)] has been linked with peripheral arterial disease (PAD). Also, elevated Lp(a) serum levels have been observed in women and African Americans (AAs). It remains uncertain if sex and ethnicity modify the association between Lp(a) and PAD. METHODS: Lp(a) mass concentration was measured with a latex-enhanced turbidimetric immunoassay, from blood collected at baseline clinic visits after a 12-hour fast, in a multiethnic cohort. Also at baseline, the ankle-brachial index was measured. PAD was defined as an ankle-brachial index <1.0. Multivariable logistic regression was used to determine sex and ethnic differences in associations of log-transformed Lp(a) and the presence of PAD. RESULTS: In 4618 participants, the mean age was 62 ± 10 years; Lp(a) mean was 30 ± 32 mg/dL and median (interquartile range) was 18 (8-40 mg/dL); 48% were male; 36% were European American, 29% were AA, 23% were Hispanic American (HA), and 12% were Chinese American; and 11% had PAD. Across all ethnic groups, serum Lp(a) was higher among women compared with men and highest among AAs compared with other ethnicities. After adjustments for traditional cardiovascular disease risk factors (age, sex, ethnicity, hypertension, diabetes, smoking, total cholesterol, and high-density lipoprotein cholesterol) as well as interleukin-6, fibrinogen, D-dimer, and homocysteine levels, one log unit increase in Lp(a) was associated with greater odds for PAD (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.01-1.25). In fully adjusted models, significant gender(∗)ln[Lp(a)] and ethnicity(∗)ln[Lp(a)] interactions were observed (P = .08 for both). The association between higher Lp(a) and PAD was strongest in HA men (OR, 1.73; 95% CI, 1.07-2.80) and HA women (OR, 1.49; 95% CI, 1.07-2.08). Nonsignificant associations were observed for European American, AA, and Chinese American men and women. CONCLUSIONS: We observed a significant and independent association between elevated Lp(a) and PAD only among HA women and men, despite higher serum Lp(a) levels among AAs. Future studies are needed to determine the role that lowering of Lp(a) may have on the burden of PAD in HAs.

Lower Aorto-Iliac Bifurcation Position and Incident Cardiovascular Disease: A Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: With increasing age, a downward shift of the aorto-iliac bifurcation relative to the lumbar spine occurs. A lower bifurcation position is an independent marker for adverse vascular aging and is associated with increased burden of cardiovascular disease (CVD) risk factors; however, the associations between lower bifurcation position and CVD events remain unknown. METHODS: Abdominal computed tomography scans were used to measure the aorto-iliac bifurcation distance (AIBD, distance from the aorto-iliac bifurcation to the L5/S1 disc space). Cox proportional hazard analysis was used to determine the independent hazard of a lower bifurcation position (smaller AIBD) for incident coronary heart disease (CHD, defined as myocardial infarction, resuscitated cardiac arrest, or sudden cardiac death), CVD (CHD plus stroke or stroke death), and all-cause mortality (ACM). RESULTS: In the 1,711 study participants (51% male), the mean AIBD was 26 ± 15 mm. After a median follow-up of 10 years, 63 (3.7%) developed CHD, 100 (5.8%) developed CVD, and 129 (7.5%) were deceased. Compared to the 4th quartile of AIBD (highest bifurcation position), participants in the 1st quartile (lowest bifurcation position) had increased risk for CHD (hazard ratio (HR) = 1.5, 95% confidence interval (CI): 0.8-3.0, P = 0.2), CVD (HR = 1.8, 95% CI: 0.9-2.7, P = 0.1), and ACM (HR = 2.2, 95% CI: 1.3-3.6, P = 0.01). After adjustments for CVD risk factors, the HR for ACM was no longer significant. CONCLUSION: Despite being an independent marker for adverse vascular changes in the aorta, a lower aorto-iliac bifurcation position was not independently associated with future CVD events. The opposing effects of atherosclerosis and stiffness in the aorta may, in part, explain our null findings.

Associations of body composition measures and C2, a marker for small artery elasticity: The MESA.

OBJECTIVE: Lower C2, a continuous blood pressure waveform characteristic asserted to represent small artery elasticity, predicts future cardiovascular disease events. It is hypothesized that the paradoxical positive association between body mass index (BMI) and C2 may reflect muscle instead of excess fat. METHODS: In a multi-ethnic, community-living cohort of 1,960 participants, computed tomography scans of the abdomen were used to measure visceral adipose tissue (VAT) and total abdominal muscle tissue (TAMT), and applanation tonometry of the radial arteries was used to assess C2. The period cross-sectional associations between BMI, TAMT, and VAT with C2 were ascertained. RESULTS: The mean age was 62 ± 9 years and 51% were male. After adjustments for age, gender, ethnicity, pack years smoking cigarettes, diabetes, hypertension, and total and HDL cholesterol, higher BMI (standardized beta = 0.09, P-value < 0.01) and more TAMT (standardized beta = 0.12, P-value < 0.01) were significantly associated with higher C2. In contrast, more VAT (standardized beta = -0.09, P-value < 0.01) was associated with lower C2. CONCLUSIONS: In multivariable analysis, VAT, in contrast to TAMT and BMI, was associated with less compliant small arteries. Visceral fat may be a better marker for detrimental excess body fat than BMI.

In vivo breath-hold (1) H MRS simultaneous estimation of liver proton density fat fraction, and T1 and T2 of water and fat, with a multi-TR, multi-TE sequence.

PURPOSE: To examine the intra-examination repeatability of proton density fat fraction (PDFF) and T1 and T2 of liver water and fat as estimated by a novel multi-repetition time (TR)-echo time (TE) (1) H magnetic resonance spectroscopy (MRS)-stimulated echo acquisition mode (STEAM) sequence that acquires 32 spectra for a range of TRs and TEs in single breath-hold. MATERIALS AND METHODS: Sixty-seven subjects undergoing liver MRI examinations at 3T had three multi-TR-TE sequences acquired consecutively in a single session. This sequence was designed to allow accurate estimation of T1 and T2 of both water and fat, as well as PDFF, in a single breath-hold. A standard long-TR, multi-TE sequence was also acquired to allow comparison of estimated PDFF. Regression and interclass correlation (ICC) analyses were performed. RESULTS: There was strong agreement between PDFF estimated by the multi-TR-TE and long-TR, multi-TE sequences (slope 0.997; intercept -0.03; R = 0.997). The multi-TR-TE sequence had high repeatability for estimating PDFF (ICC = 0.999), water T2 (ICC = 0.920), water T1 (ICC = 0.845), and fat T2 (ICC = 0.760), and moderate repeatability for estimating fat T1 (ICC = 0.556). CONCLUSION: A novel multi-TR-TE sequence can estimate PDFF and water and fat T1 and T2 in a single breath-hold. Refinement may be needed to improve repeatability for fat T1 estimation.

Association of foot and ankle characteristics with progression of venous disease.

Although risk factors have been identified for the cross-sectional prevalence of venous disease, few studies have investigated risk factors for venous disease progression. Therefore, the aim of this study was to investigate the relationship between foot and ankle characteristics and the progression of venous disease. A total of 1025 participants from the San Diego Population Study were assessed at baseline and at follow-up 11 years later. Risk factors were assessed by questionnaire and physical measurements, while venous disease was determined by physical examination and Duplex ultrasound. Change in venous disease from baseline to 11-year follow-up was characterized as stable or progression. Those with venous disease progression were less likely to spend increased time lying per day, more likely to have a history of hypertension, lie supine for a surgical procedure greater than an hour, and report an occupation that was professional, technical, administrative, or management. Those with a normal arch reported the greatest degree of plantar flexion. In multivariable logistic regression, including adjustment for weight-bearing arch characteristics, greater dorsiflexion (per 5 degrees) was significantly associated with progression of venous disease (OR = 1.11, p = 0.01). A weight-bearing flat arch compared to a weight-bearing normal arch was of borderline significance as a protective factor against progression of venous disease with adjustment for dorsiflexion (OR = 0.56, p = 0.07). Our results indicate that the ability to have higher levels of dorsiflexion is a risk factor for the progression of venous disease, and suggest a role for connective tissue laxity in the pathogenesis of venous disease.

Associations of cardiovascular disease risk factors and calcified atherosclerosis with aortoiliac bifurcation position: the MultiEthnic Study of Atherosclerosis.

We investigated associations of cardiovascular disease (CVD) risk factors and calcified atherosclerosis with aortoiliac bifurcation position. The bifurcation position was determined by measuring the distance from the aortoiliac bifurcation to the L5-S1 disk space (or aortoiliac bifurcation distance [AIBD]), using computed tomography scans. The 1711 study participants (51% male) had a mean age of 62 ± 10 years and a mean AIBD of 26 ± 15 mm. In multivariable linear regression, older age, male gender, smoking, hypertension, larger aortic diameter, and smaller lumbar height were each independently associated with a smaller AIBD (more caudal bifurcation position). In contrast, diabetes, elevated triglycerides, and increased pulse pressure were independently associated with a larger AIBD (more cephalad bifurcation position). These findings suggest that age-related bifurcation descent is associated with CVD markers for aortic disease. Future studies should assess whether the bifurcation position is an independent prognosticator for CVD.