Nutritional Avocado Intervention Improves Physical Activity Measures in Hispanic/Latino Families: A Cluster RCT

Introduction

Nutrition and physical activity are key components for the prevention of cardiovascular disease. There remains a paucity of trial data on the effect of specific nutritional interventions on physical activity and sedentary time. One question is how a common nutrient-dense food such as avocado may impact physical activity and sedentary time in Hispanic/Latino families, a group that reports the lowest levels of physical activity.

Design

This is a 6-month clustered RCT.

Setting/participants

Seventy-two families (235 individuals) who identified as Hispanic/Latino were enrolled through the San Ysidro Health Center (San Diego, CA) between April 2017 and June 2018.

Intervention

After a 2-week run-in period, 35 families were randomized to the intervention arm (14 avocados/family/week), and 37 families were assigned to the control arm (3 avocados/family/week).

Main outcome measures

Linear mixed-effects models were used to assess changes in physical activity (MET minutes per week) between the groups during the 6-month trial. Secondary outcomes included sedentary time (minutes/week), BMI, and systolic and diastolic blood pressures.

Results

An adherence goal of >80% was achieved for both arms. Total mean physical activity increased by 2,197 MET minutes per week more in the intervention group (p<0.01) than in the control group, driven by between-group differences in moderate (p<0.01) versus vigorous (p=0.06) physical activity. After accounting for longitudinal repeated measures per participant and nested family effects, total adult physical activity remained significantly higher in the intervention than in the control group (+1,163 MET minutes per week on average per participant), with a significant intervention interaction term (p<0.01). There were no significant changes in sedentary time, BMI, or blood pressure.

Conclusions

Higher allocation of avocados was associated with significantly higher physical activity and no adverse changes in BMI or blood pressure, suggesting that this nutritional intervention may have beneficial pleiotropic effects.Trial registration: This study is registered at www.clinicaltrials.gov as NCT02903433.

The association between arterial compliance, as assessed by PTC1 and PTC2 from radial artery waveforms, and age, sex, and race/ethnicity

BACKGROUND

There is limited literature on differences in arterial compliance, as assessed from arterial pressure waveforms, with age, sex, and race/ethnicity. PTC1 and PTC2 are indices of arterial compliance, which are derived from a Windkessel model of the waveform, relatively easy to obtain, and associated with cardiovascular disease.

METHOD

PTC1 and PTC2 were computed from radial artery waveforms from participants of the Multi-Ethnic Study of Atherosclerosis at baseline and again 10 years later. We evaluated the association of PTC1, PTC2, and 10-year change in PTC1 and PTC2 with age, sex, and race/ethnicity.

RESULTS

Among 6245 participants in 2000-2002 (mean ± SD of age was 62 ± 10 years; 52% female; 38% White, 12% Chinese, 27% Black, and 23% Hispanic/Latino), means ± SDs for PTC1 and PTC2 were 394 ± 334 and 94 ± 46 ms. After adjustment for cardiovascular disease risk factors, mean PTC2 was 1.1 ms (95% confidence interval: 1.0, 1.2) lower (arterial stiffness was greater) per year older age, was 22 ms (19, 24) lower for females, and varied by race/ethnicity ( P  < 0.001; e.g., 5 ms lower for Blacks compared with Whites), although the differences were smaller at older ages ( P  < 0.001 for age-sex, P  < 0.001 for age-race/ethnicity interactions). Among 3701 participants with repeat measurements in 2010-2012, arteries had stiffened (mean ± SD 10-year decrease in PTC2: 13 ± 46 ms) consistent with cross-sectional age-trend and tended to stiffen less for females and Blacks consistent with cross-sectional age-interactions.

CONCLUSION

Differences in arterial compliance by age, sex, and race/ethnicity lend support to identify and act on societal factors that may drive health disparities.

Abstract P667: Association of Number of Calcified Coronary Arteries and Cardiovascular Outcomes Stratified by Calcification Volume: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background: Coronary artery calcium (CAC) is a risk factor for atherosclerotic cardiovascular disease (ASCVD). Data suggests number of vessels with CAC independently improves risk prediction but impact by CAC volume remains unknown.

Methods: Using data from 3256 MESA participants with CAC>0 and clinical follow-up, we evaluated the association between number of arteries with CAC and risk for coronary heart disease (CHD), myocardial infarction (MI), and CVD events stratified by CAC volume (above/below median) using multivariable-adjusted Cox proportional hazards models.

Results: Mean age was 63.3 years (SD 9.5) with 1363 (41.9%) women. There were 1079 (33%) with single-vessel, 822 (25%) with 2-vessel, and 1355 (42%) with 3-4 vessel CAC. Median CAC volume was 84.7 [IQR 24.5, 267.2] mm 3 . CAC in 3-4 vessels was independently associated with higher CHD risk ( Figure ) compared to 1-vessel (HR 2.01, 95% CI 1.1-3.6; p=0.018) and 2-vessels (HR 1.69, 95% CI 1.0-2.8; p=0.04) for lower CAC volumes, with similar findings for MI and CVD outcomes ( Table ).

Conclusions: Number of arteries with CAC independently increases risk for ASCVD events only for those with lower CAC volumes.

Abstract P139: Association Of Thoracic Aorta Calcification And Aortic Arch Stiffness: The Multi-ethnic Study Of Atherosclerosis

Background: Arterial stiffness (AS) is a robust risk factor for HTN and CVD. It remains unclear how thoracic aortic calcification (TAC) presence, volume, and density relate to AS in the aortic arch. Improved understanding of central AS may provide insight to future mechanistic approaches to prevent and control CVD.

Methods: We evaluated 1,385 participants from MESA Exam 5 with TAC data throughout the thoracic aorta via Chest CT and pulse wave velocity (PWV) as a measure of AS across the aortic arch via MRI. We used linear regression models to assess cross-sectional associations of TAC presence, volume, and density with aortic arch PWV with adjustment for 1) age, sex, and race; and 2) age, sex, race, BMI, diabetes, estimated glomerular filtration rate, HTN-medication use, SBP, DBP, total cholesterol/high-density lipoprotein ratio, smoking status, CAC volume, CAC density, education, physical activity, and sedentary behavior.

Results: Participants were a mean age of 69 years (SD 9) [717 (52%) female; 509 (37%) White, 359 (26%) Black, 285 (21%) Hispanic/Latino, and 232 (17%) Chinese]. Calcification was present in 1,263 (91%) and 1,228 (89%) participants in the entire thoracic aorta and aortic arch, respectively, compared to 848 (61%) and 138 (10%) in the descending and ascending aorta segments. Calcium volume in the entire thoracic aorta and aortic arch were highly correlated (r=0.94) with respective means of 866 (SD 1,724) and 564 (1,014) mm 3 . Mean PWV across the aortic arch was 9 m/sec (SD 4). After full adjustment, the presence of aortic arch calcification, compared to no aortic arch calcification, was associated with a 0.76 m/sec higher mean PWV (95% CI: 0.34 - 1.18; p<0.01), while a 1,000 mm 3 increment in aortic arch calcium volume was associated with 0.36 m/sec higher mean PWV (95% CI: 0.08-0.64; p=0.01). Results were similar when calcification in the entire thoracic aorta was the primary predictor variable. Conversely, there were no significant associations between mean or maximum calcium density measures and aortic arch PWV.

Conclusion: TAC is highly prevalent in the thoracic aorta, especially the aortic arch. Calcification presence and higher calcification volume in the thoracic aorta, as well as the aortic arch itself, are associated with greater aortic arch AS.

Effects of Different Allotments of Avocados on the Nutritional Status of Families: A Cluster Randomized Controlled Trial

Avocados are a nutrient-dense plant-food, but limited trial-derived evidence exists about the effects of avocado intake on family nutritional status. We investigated the impact of two levels of avocado allotment, plus a standard nutrition education intervention on the nutritional status of Hispanic/Latino families. Seventy-two families consisting of at least three members of ≥5 years of age and residing in the same home, free of severe chronic disease, not on specific diets, and self-identified of Hispanic heritage, were randomized to one of two levels of avocado allotment (low = 3/week/family or high = 14/week/family) for 6 months plus 12 bi-weekly nutrition education sessions. The primary outcomes included change in a family’s total energy and macro- and micronutrient intakes. Primary analysis was intention-to-treat with unpaired, two-sided t-tests to assess mean changes between groups at 6 months. At 6 months, the high avocado allotment group had a significant reduction in energy intake, carbohydrate, animal and vegetable protein, saturated and polyunsaturated fat, calcium, magnesium, sodium, potassium, iron, and vitamin D intakes (all p < 0.05). A high allotment of avocados significantly reduced self-reported energy intake by 29% kcal/family/day, compared to a 3% kcal/family/day reduction in families who received a low allotment. Culturally-appropriate plant-food interventions may alter the nutritional status of at-risk families.

The association between indices of blood pressure waveforms (PTC1 and PTC2) and incident heart failure

OBJECTIVES

The radial artery pulse waveform is a continuous measure of pressure throughout the cardiac cycle, and thus can provide more information than just systolic and diastolic blood pressures. New indices based on a Windkessel model of the waveform, PTC1 and PTC2, are related to arterial compliance and add information for prediction of incident cardiovascular disease (coronary heart disease, stroke, myocardial infarction) but their association with heart failure is unknown.

METHODS

Among 6229 adults (mean age 62 years) from four race/ethnic groups who were initially free of clinical cardiovascular disease and heart failure in 2000-2002, we evaluated the associations of baseline PTC1 and PTC2 with incident heart failure.

RESULTS

Mean ± standard deviation PTC1 and PTC2 were 394 ± 334 and 94 ± 46 ms, respectively. During a median of 15.7 years follow-up, there were 357 heart failure events (148 with reduced, 150 with preserved, and 59 with unknown ejection fraction). After adjustment for traditional risk factors, the hazard ratio for heart failure per 1 standard deviation higher PTC2 was 0.73 (95% confidence interval: 0.63--0.85). Higher PTC2 was also significantly associated with lower risk of heart failure with reduced ejection fraction (hazard ratio = 0.67; 95% confidence interval: 0.56--0.80). There was no evidence of a significant association between PTC2 and heart failure with preserved ejection fraction or between PTC1 and heart failure.

CONCLUSION

The PTC2 measure of the radial artery pulse waveform may represent a novel phenotype related to heart failure, especially heart failure with reduced ejection fraction.

Associations of Perirenal Fat Thickness with Renal and Systemic Calcified Atherosclerosis

BACKGROUND

We investigated associations between perirenal fat thickness and atherosclerotic calcification in six different vascular beds.

METHODS

Using a community-based cohort (n=3,919), perirenal fat thickness was estimated from computed tomography scans. It was classified as Q1 (the lowest quartile) to Q4 (the highest quartile) in each sex. Calcification in the carotid arteries, coronary arteries, thoracic aorta, abdominal aorta, iliac arteries, and renal arteries was evaluated.

RESULTS

Perirenal fat thickness was associated with older age (P<0.01) and a higher prevalence of obesity, hypertension, and dyslipidemia (P<0.01 for all). Perirenal fat thickness was independently associated with renal arterial calcification even after adjustment for age, sex, body mass index, hypertension, dyslipidemia, smoking history, and family history of heart diseases in first-degree relatives (odds ratio [OR] per quartile of perirenal fat thickness, 1.25; 95% confidence interval [CI], 1.09 to 1.44). Compared to Q1, the odds of renal arterial calcification in Q4 was about two times higher (OR, 2.05; 95% CI, 1.29 to 3.25). After adjustment for renal arterial calcification and atherosclerotic risk factors, the only other vascular bed where perirenal fat thickness showed a significant association with calcification was the abdominal aorta (OR, 1.11; 95% CI, 1.00 to 1.23; P=0.045).

CONCLUSION

Perirenal fat thickness was independently associated with vascular calcification in the renal artery and abdominal aorta.

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.

Predictors of Change in the Ankle Brachial Index with Exercise

OBJECTIVE

A 20% or greater decrease in the ankle brachial index (ABI) with exercise is suggestive of peripheral artery disease (PAD), and could identify patients with an increased mortality risk. The predictors of a change in the ABI with exercise have received little attention.

METHODS

This was a cross-sectional analysis. Two hundred and sixty five participants of the San Diego Population Study with a resting ABI between 0.90 and 1.10 performed 50 heel raises and immediately had their ABIs measured again. The relationship between the change in the ABI with exercise and multiple potential risk prediction variables were examined using linear regression. In addition, the categorical percent change in the ABI with exercise was analysed by multinomial logistic regression.

RESULTS

The mean age of participants was 71.8 years, and 80.4% were female. At rest, the average ABI was 1.04 (SD 0.04) before and 0.94 (SD 0.13) after exercise; a mean decrease of 9.5%. In analyses of ABI change as a continuous variable, higher age, any smoking history, and a diagnosis of chronic obstructive pulmonary disease (COPD) were associated with a significant decrease in the ABI with exercise (p = .01, .04, and .03, respectively). Categorical analyses of the risk factors associated with a 20% or greater ABI decrease with exercise confirmed these results. Congestive heart failure was associated with an increased ABI with exercise (p = .04) in continuous ABI change analyses only.

CONCLUSIONS

Older age, a positive history of smoking, and a history of COPD were independently and significantly associated with a greater ABI decrease with exercise. These risk variables may help identify persons with subclinical PAD.

Peripheral Artery Disease and Aortic Disease

We reviewed published MESA (Multi-Ethnic Study of Atherosclerosis) study articles concerning peripheral arterial disease, subclavian stenosis (SS), abdominal aortic calcium (AAC), and thoracic artery calcium (TAC). Important findings include, compared to non-Hispanic whites, lower ankle-brachial index (ABI) and more SS in African Americans, and higher ABI and less SS in Hispanic and Chinese Americans. Abnormal ABI and brachial pressure differences were associated with other subclinical cardiovascular disease (CVD) measures. Both very high and low ABI independently predicted increased CVD events. Looking at aortic measures, TAC and AAC were significantly associated with other subclinical CVD measures. Comparisons of AAC with coronary artery calcium (CAC) showed that both were less common in ethnic minority groups. However, although CAC was much more common in men than in women in multivariable analysis, this was not true of AAC. Also, when AAC and CAC were adjusted for each other in multivariable analysis, there was a stronger association for AAC than for CAC with CVD and total mortality.

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 β=0.44 (95% CI 0.31 to 0.58) ln-units) but a lower CAC density score (β=-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 (β=-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 (β= 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.

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.

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.

A genetic risk score comprising known venous thromboembolism loci is associated with chronic venous disease in a multi-ethnic cohort

BACKGROUND

Chronic venous disease is common and shares some risk factors with venous thromboembolism (VTE). Several genetic loci have been discovered and well-replicated for VTE in European descent populations. We examined associations of a genetic risk score (GRS), comprising known VTE loci, with chronic venous disease.

METHODS

The San Diego Population Study (SDPS) is a multi-ethnic cohort that evaluated 2404 men and women aged 29-91 from 1994 to 1998 for chronic venous disease. The current study includes 1447 participants genotyped for 33 variants in 22 established VTE risk loci. Using these variants, unweighted and weighted GRS were constructed. Logistic regression was used to examine associations with venous disease.

RESULTS

In non-Hispanic whites, African-Americans, Hispanics, and Asians, each standard deviation increment higher of the unweighted 33-SNP GRS was associated with a 1.45-fold (95% CI (1.26, 1.67)), 1.74-fold (1.18, 2.55), a 1.80-fold (1.30, 2.51), and 1.88-fold (1.30, 2.73) greater odds, respectively, for moderate plus severe disease. The difference in c-statistics was significant between a known venous risk factor model and a model adding the 33-SNP GRS for whites (p=0.008), African-Americans (0.03), and Hispanics (p=0.04), with marginal significance in Asians (p=0.06).

CONCLUSIONS

GRS comprising variants primarily from VTE findings in European descent populations were associated with chronic venous disease across all race/ethnic groups, and contributed significantly to prediction, indicating some level of generalizability to other race/ethnic groups. Future work should focus on more in depth examination of racial/ethnic group genetic architecture in relation to chronic venous disease.

Global and regional burden of aortic dissection and aneurysms: mortality trends in 21 world regions, 1990 to 2010

A comprehensive and systematic assessment of the global burden of aortic aneurysms (AA) has been lacking. Therefore, we estimated AA regional deaths and years of life lost (YLL) in 21 regions worldwide for 1990 and 2010. We used the GBD (Global Burden of Disease) 2010 study causes of death database and the cause of death ensemble modeling approach to assess levels and trends of AA deaths by age, sex, and GBD region. The global AA death rate per 100,000 population was 2.49 (95% CI: 1.78 to 3.27) in 1990 and 2.78 (95% CI: 2.04 to 3.62) in 2010. In 1990 and 2010, the highest mean death rates were in Australasia and Western Europe: 8.82 (95% CI: 6.96 to 10.79) and 7.69 (95% CI: 6.11 to 9.57) in 1990 and 8.38 (95% CI: 6.48 to 10.86) and 7.68 (95% CI: 6.13 to 9.54) in 2010. YLL rates by GBD region mirrored the mortality rate pattern. Overall, men had higher AA death rates than women: 2.86 (95% CI: 1.90 to 4.22) versus 2.12 (95% CI: 1.33 to 3.00) in 1990 and 3.40 (95% CI: 2.26 to 5.01) versus 2.15 (95% CI: 1.44 to 2.89) in 2010. The relative change in median death rate was +0.22 (95% CI: 0.10 to 0.33) in developed nations versus +0.71 (95% CI: 0.28 to 1.40) in developing nations. The smallest relative changes in median death rate were noted in North America high income, Central Europe, Western Europe, and Australasia, with estimates of +0.07 (95% CI: -0.26 to 0.37), +0.08 (95% CI: -0.02 to 0.23), +0.09 (95% CI: -0.02 to 0.21), and +0.22 (95% CI: -0.08 to 0.46), respectively. The largest increases were in Asia Pacific high income, Southeast Asia, Latin America tropical, Oceania, South Asia, and Central Sub-Saharan Africa. Women rather than men drove the increase in the Asia Pacific high-income region: the relative change in median rates was +2.92 (95% CI: 0.6 to 4.35) versus +1.05 (95% CI: 0.61 to 2.42). In contrast to high-income regions, the observed pattern in developing regions suggests increasing AA burden, which portends future health system challenges in these regions.

Abdominal aortic calcium, coronary artery calcium, and cardiovascular morbidity and mortality in the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To evaluate the predictive value of abdominal aortic calcium (AAC) for incident cardiovascular disease (CVD) independent of coronary artery calcium (CAC).

APPROACH AND RESULTS

We evaluated the association of AAC with CVD in 1974 men and women aged 45 to 84 years randomly selected from the Multi-Ethnic Study of Atherosclerosis participants who had complete AAC and CAC data from computed tomographic scans. AAC and CAC were each divided into following 3 percentile categories: 0 to 50th, 51st to 75th, and 76th to 100th. During a mean of 5.5 years of follow-up, there were 50 hard coronary heart disease events, 83 hard CVD events, 30 fatal CVD events, and 105 total deaths. In multivariable-adjusted Cox models including both AAC and CAC, comparing the fourth quartile with the ≤ 50th percentile, AAC and CAC were each significantly and independently predictive of hard coronary heart disease and hard CVD, with hazard ratios ranging from 2.4 to 4.4. For CVD mortality, the hazard ratio was highly significant for the fourth quartile of AAC, 5.9 (P=0.01), whereas the association for the fourth quartile of CAC (hazard ratio, 2.1) was not significant. For total mortality, the fourth quartile hazard ratio for AAC was 2.7 (P=0.001), and for CAC, it was 1.9, P=0.04. Area under the receiver operating characteristic curve analyses showed improvement for both AAC and CAC separately, although improvement was greater with CAC for hard coronary heart disease and hard CVD, and greater with AAC for CVD mortality and total mortality. Sensitivity analyses defining AAC and CAC as continuous variables mirrored these results.

CONCLUSIONS

AAC and CAC predicted hard coronary heart disease and hard CVD events independent of one another. Only AAC was independently related to CVD mortality, and AAC showed a stronger association than CAC with total mortality.

Risk marker associations with venous thrombotic events: a cross-sectional analysis

OBJECTIVE

To examine the interrelations among, and risk marker associations for, superficial and deep venous events-superficial venous thrombosis (SVT), deep venous thrombosis (DVT) and pulmonary embolism (PE).

DESIGN

Cross-sectional analysis.

SETTING

San Diego, California, USA.

PARTICIPANTS

2404 men and women aged 40-79 years from four ethnic groups: non-Hispanic White, Hispanic, African-American and Asian. The study sample was drawn from current and former staff and employees of the University of California, San Diego and their spouses/significant others.

OUTCOME MEASURES

Superficial and deep venous events, specifically SVT, DVT, PE and combined deep venous events (DVE) comprising DVT and PE.

RESULTS

Significant correlates on multivariable analysis were, for SVT: female sex, ethnicity (African-American=protective), lower educational attainment, immobility and family history of varicose veins. For DVT and DVE, significant correlates included: heavy smoking, immobility and family history of DVEs (borderline for DVE). For PE, significant predictors included immobility and, in contrast to DVT, blood pressure (BP, systolic or diastolic). In women, oestrogen use duration for hormone replacement therapy, in all and among oestrogen users, predicted PE and DVE, respectively.

CONCLUSIONS

These findings fortify evidence for known risk correlates/predictors for venous disease, such as family history, hormone use and immobility. New risk associations are shown. Striking among these is an association of PE, but not DVT, to elevated BP: we conjecture PE may serve as cause rather than consequence. Future studies should evaluate the temporal direction of this association. Oxidative stress and cell energy compromise are proposed to explain and predict many risk factors, operating through cell-death mediated triggering of coagulation activation.

Ankle-brachial index, toe-brachial index, and cardiovascular mortality in persons with and without diabetes mellitus

BACKGROUND

The prognostic utility of the ankle-brachial index (ABI) may be hampered in persons with diabetes due to peripheral arterial stiffening in the ankles. Stiffening of toe arteries occurs infrequently in diabetes. We aimed to determine the nature of the relationship of the toe-brachial index (TBI) and ABI with cardiovascular disease (CVD) mortality and to determine whether the associations are modified in individuals with diabetes.

METHODS

Individuals with clinically suspected atherosclerotic peripheral arterial disease who underwent ABI and TBI measurements in a vascular laboratory were monitored longitudinally for CVD mortality.

RESULTS

Among 469 participants (89% men), the mean age was 68 ± 9 years, and 36% had diabetes. The mean ABI was 0.83 ± 0.28 and the mean TBI was 0.60 ± 0.24. During median 7.0 years of follow-up, there were 158 CVD deaths. The association of the ABI categories with CVD deaths differed in diabetic vs nondiabetic participants (P = .002 for interaction). In contrast, the association of the TBI categories with CVD deaths was similar, irrespective of diabetes status (P = .17 for interaction). Among diabetic patients, a U-shaped relationship was observed between ABI categories and CVD death: those with low (<0.90) and high (>1.30) ABIs were both at higher risk than those with normal ABIs (range, 0.90-1.30). In nondiabetic patients, association of ABI categories with CVD death was linear, such that those with an ABI >1.30 were at the lowest risk, whereas those with an ABI <0.90 were at higher risk. In contrast, the association of TBI categories with CVD death was linear irrespective of diabetes status. High TBI categories consistently predicted low risk, whereas risk was higher with progressively lower TBI categories.

CONCLUSIONS

Among diabetic individuals with clinically suspected peripheral arterial disease, those with low and high ABIs are both at higher risk of CVD death. In contrast, a linear relationship was observed between TBI categories and CVD death irrespective of diabetes status. These findings suggest that stiffened ankle arteries may limit the predictive value of the ABI in individuals with diabetes, a limitation that may be overcome by measurement of the TBI.

Calcium density of coronary artery plaque and risk of incident cardiovascular events

IMPORTANCE

Coronary artery calcium (CAC), measured by computed tomography (CT), has strong predictive value for incident cardiovascular disease (CVD) events. The standard CAC score is the Agatston, which is weighted upward for greater calcium density. However, some data suggest increased plaque calcium density may be protective for CVD.

OBJECTIVE

To determine the independent associations of CAC volume and CAC density with incident CVD events.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, prospective observational MESA study (Multi-Ethnic Study of Atherosclerosis), conducted at 6 US field centers of 3398 men and women from 4 race/ethnicity groups; non-Hispanic white, African American, Hispanic, and Chinese. Participants were aged 45-84 years, free of known CVD at baseline, had CAC greater than 0 on their baseline CT, and were followed up through October 2010.

MAIN OUTCOMES AND MEASURES

Incident coronary heart disease (CHD) and all CVD events

RESULTS

During a median of 7.6 years of follow-up, there were 175 CHD events and an additional 90 other CVD events for a total of 265 CVD events. With both lnCAC volume and CAC density scores in the same multivariable model, the lnCAC volume score showed an independent association with incident CHD, with a hazard ratio (HR) of 1.81 (95% CI, 1.47-2.23) per standard deviation (SD = 1.6) increase, absolute risk increase 6.1 per 1000 person-years, and for CVD an HR of 1.68 (95% CI, 1.42-1.98) per SD increase, absolute risk increase 7.9 per 1000 person-years. Conversely, the CAC density score showed an independent inverse association, with an HR of 0.73 (95% CI, 0.58-0.91) per SD (SD = 0.7) increase for CHD, absolute risk decrease 5.5 per 1000 person-years, and an HR of 0.71 (95% CI, 0.60-0.85) per SD increase for CVD, absolute risk decrease 8.2 per 1000 person years. Area under the receiver operating characteristic curve analyses showed significantly improved risk prediction with the addition of the density score to a model containing the volume score for both CHD and CVD. In the intermediate CVD risk group, the area under the curve for CVD increased from 0.53 (95% CI, 0.48-0.59) to 0.59 (95% CI, 0.54-0.64), P = .02.

CONCLUSIONS AND RELEVANCE

CAC volume was positively and independently associated with CHD and CVD risk. At any level of CAC volume, CAC density was inversely and significantly associated with CHD and CVD risk. The role of CAC density should be considered when evaluating current CAC scoring systems.

Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and analysis

BACKGROUND

Lower extremity peripheral artery disease is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. This study provides the first comparison of the prevalence of peripheral artery disease between high-income countries (HIC) and low-income or middle-income countries (LMIC), establishes the primary risk factors for peripheral artery disease in these settings, and estimates the number of people living with peripheral artery disease regionally and globally.

METHODS

We did a systematic review of the literature on the prevalence of peripheral artery disease in which we searched for community-based studies since 1997 that defined peripheral artery disease as an ankle brachial index (ABI) lower than or equal to 0·90. We used epidemiological modelling to define age-specific and sex-specific prevalence rates in HIC and in LMIC and combined them with UN population numbers for 2000 and 2010 to estimate the global prevalence of peripheral artery disease. Within a subset of studies, we did meta-analyses of odds ratios (ORs) associated with 15 putative risk factors for peripheral artery disease to estimate their effect size in HIC and LMIC. We then used the risk factors to predict peripheral artery disease numbers in eight WHO regions (three HIC and five LMIC).

FINDINGS

34 studies satisfied the inclusion criteria, 22 from HIC and 12 from LMIC, including 112,027 participants, of which 9347 had peripheral artery disease. Sex-specific prevalence rates increased with age and were broadly similar in HIC and LMIC and in men and women. The prevalence in HIC at age 45-49 years was 5·28% (95% CI 3·38-8·17%) in women and 5·41% (3·41-8·49%) in men, and at age 85-89 years, it was 18·38% (11·16-28·76%) in women and 18·83% (12·03-28·25%) in men. Prevalence in men was lower in LMIC than in HIC (2·89% [2·04-4·07%] at 45-49 years and 14·94% [9·58-22·56%] at 85-89 years). In LMIC, rates were higher in women than in men, especially at younger ages (6·31% [4·86-8·15%] of women aged 45-49 years). Smoking was an important risk factor in both HIC and LMIC, with meta-OR for current smoking of 2·72 (95% CI 2·39-3·09) in HIC and 1·42 (1·25-1·62) in LMIC, followed by diabetes (1·88 [1·66-2·14] vs 1·47 [1·29-1·68]), hypertension (1·55 [1·42-1·71] vs 1·36 [1·24-1·50]), and hypercholesterolaemia (1·19 [1·07-1·33] vs 1·14 [1·03-1·25]). Globally, 202 million people were living with peripheral artery disease in 2010, 69·7% of them in LMIC, including 54·8 million in southeast Asia and 45·9 million in the western Pacific Region. During the preceding decade the number of individuals with peripheral artery disease increased by 28·7% in LMIC and 13·1% in HIC.

INTERPRETATION

In the 21st century, peripheral artery disease has become a global problem. Governments, non-governmental organisations, and the private sector in LMIC need to address the social and economic consequences, and assess the best strategies for optimum treatment and prevention of this disease.

FUNDING

Peripheral Arterial Disease Research Coalition (Europe).

Family history of peripheral artery disease is associated with prevalence and severity of peripheral artery disease: the San Diego population study

OBJECTIVES

The purpose of this study was to determine the association of family history of peripheral artery disease (PAD) with PAD prevalence and severity.

BACKGROUND

PAD is a significant public health problem. Shared genetic and environmental factors may play an important role in the development of PAD. However, family history of PAD has not been investigated adequately.

METHODS

The San Diego Population Study enrolled 2,404 ethnically diverse men and women 29 to 91 years of age who attended a baseline visit from 1994 through 1998 to assess PAD and venous disease. Ankle brachial index measurement was performed at the baseline clinic examination, and family history of PAD was obtained via questionnaire. Family history of PAD was defined primarily as having any first-degree relative with PAD. Prevalent PAD was defined as ankle brachial index ≤ 0.90, and severe prevalent PAD was defined as ankle brachial index ≤ 0.70, with both definitions also including any previous leg revascularization. Logistic regression was used to evaluate the association of family history of PAD with prevalent PAD.

RESULTS

The mean age was 59 ± 11 years, 66% were women, and 58% were Caucasian, with 42% representing other racial or ethnic groups. Prevalence of PAD was 3.6%, and severe prevalent PAD was 1.9%. In fully adjusted models, family history of PAD was associated with a 1.83-fold higher odds of PAD (95% confidence interval: 1.03 to 3.26, p = 0.04), an association that was stronger for severe prevalent PAD (odds ratio: 2.42, 95% confidence interval: 1.13 to 5.23, p = 0.02).

CONCLUSIONS

Family history of PAD is independently strongly associated with PAD prevalence and severity. This indicates a role for genetic factors or other shared environmental factors, or both, contributing to PAD.

Statin-associated muscle-related adverse effects: a case series of 354 patients

STUDY OBJECTIVE

To characterize the properties and natural history of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin)-associated muscle-related adverse effects (MAEs).

DESIGN

Patient-targeted postmarketing adverse-effect surveillance approach coupling survey design with an open-ended narrative.

SETTING

University-affiliated health care system.

SUBJECTS

Three hundred fifty-four patients (age range 34-86 yrs) who self-reported muscle-related problems associated with statin therapy.

MEASUREMENTS AND MAIN RESULTS

Patients with perceived statin-associated MAEs completed a survey assessing statin drugs and dosages; characteristics of the MAEs; time course of onset, resolution, or recurrence; and impact on quality of life (QOL). Cases were assessed for putative drug adverse-effect causality by using the Naranjo adverse drug reaction probability scale criteria and were evaluated for inclusion in groups for which mortality benefit with statins has been shown. Patients reported muscle pain (93%), fatigue (88%), and weakness (85%). Three hundred patients (85%) met literature criteria for probable or definite drug adverse-effect causality. Ninety-four percent of atorvastatin usages (240/255) generated MAEs versus 61% of lovastatin usages (38/62, p<0.0001). Higher potency statins reproduced MAEs in 100% of 39 rechallenges versus 73% (29/40) with lower potency rechallenges (p<0.01). Time course of onset after statin initiation varied (median 14 wks); some MAEs occurred after long-term symptom-free use. Recurrence with rechallenge had a significantly shorter latency to onset (median 2 wks). The MAEs adversely affected all assessed functional and QOL domains. Most patients with probable or definite MAEs were in categories for which available randomized controlled trial evidence shows no trend to all-cause mortality benefit with statin therapy.

CONCLUSION

This study complements available information on the properties and natural history of statin-associated MAEs, affirming dose dependence and strong QOL impact. The data indicating a dose-dependent relationship between MAE risk and recurrence suggest lower potency statins or discontinuation may bear consideration for ameliorating symptoms.

Adipokines are associated with lower extremity venous disease: the San Diego population study

BACKGROUND

Obesity is a risk factor for venous disease. We tested the associations between adipokines and the presence and severity of venous disease.

METHODS

Participants for this analysis were drawn from a cohort of 2408 employees and retirees of a university in San Diego who were examined for venous disease using duplex ultrasonography. From this cohort, a case-control study sample of all 352 subjects with venous disease and 352 age-, sex- and race-matched subjects without venous disease were included in this analysis. All subjects completed health history questionnaires, had a physical examination with anthropometric measurements and had venous blood analyzed for adipokines.

RESULTS

After adjustment for age, sex and race, those with venous disease had significantly higher levels of body mass index (BMI), leptin and interleukin-6. Levels of resistin and tumor necrosis factor-alpha were also higher but of borderline significance (0.05 < P < 0.10). Compared with the lowest tertile and with adjustment for age, sex, race and BMI, the 2nd and 3rd tertiles of resistin (odds ratios, 1.9 and 1.7, respectively), leptin (1.7 and 1.7) and tumor necrosis factor-alpha (1.4 and 1.7) were associated with increasing severity of venous disease. Conversely, a 5 kg m⁻² increment in BMI was associated with a higher odds ratio (1.5) for venous disease, which was independent of the adipokines included in this study.

CONCLUSIONS

Both obesity and adipokines are significantly associated with venous disease. These associations appear to be independent of each other, suggesting potentially different pathways to venous disease.

Risk factors for peripheral venous disease resemble those for venous thrombosis: the San Diego Population Study

BACKGROUND

Clinically silent deep vein thrombosis (DVT) is common and may cause chronic venous disease that resembles post-thrombotic syndrome.

OBJECTIVE

We evaluated whether peripheral venous disease in a general population shares risk factors with DVT.

METHODS

In an established cohort of 2404 men and women, the San Diego Population Study, peripheral venous disease was evaluated using physical examination, symptom assessment and venous ultrasound. We performed a case-control study including 308 cases in four hierarchical groups by severity and 346 controls without venous abnormalities, frequency matched to cases by 10-year age group, race and gender. Cases and controls had no prior history of venous thrombosis. Hemostatic risk factors were measured in cases and controls.

RESULTS

Accounting for age, obesity and family history of leg ulcer, odds ratios (ORs) of venous disease for elevated factor VIII, von Willebrand factor (VWF), D-dimer and for factor V Leiden were 1.4 (95% CI 0.9-2.1), 1.5 (CI 1.0-2.3), 1.7 (CI 1.1-2.8) and 1.1 (CI 0.5-2.4), respectively. These associations were larger for the two most severe case groups; ORs 2.0 (CI 1.0-3.8), 1.7 (CI 0.9-3.3), 2.7 (CI 1.2-6.1) and 2.3 (CI 0.8-7.1). Each hemostatic factor was also associated with severity of venous disease, for example elevated D-dimer was associated with a 2.2-fold increased odds of being in one higher severity case group. Prothrombin 20210A was not associated with venous disease.

CONCLUSIONS

DVT risk factors are associated with presence and severity of peripheral venous disease. Results support a hypothesis that peripheral venous disease may sometimes be post-thrombotic syndrome as a result of a previous unrecognized DVT.

Biomarkers in peripheral arterial disease patients and near- and longer-term mortality

BACKGROUND

Whether novel biomarkers improve risk prediction of mortality beyond standard cardiovascular disease (CVD) risk markers in peripheral arterial disease (PAD) patients, and whether any such prediction differs with length of follow-up, remains controversial. Our objective was to determine in patients with PAD whether novel biomarkers improve prediction of CVD mortality and total mortality.

METHODS

A cohort of 397 patients who were referred to a vascular lab had PAD diagnosed by noninvasive testing. Fifty-eight percent also had coronary or cerebrovascular disease at baseline. Predictors of total, CVD, and non-CVD mortality were assessed with Cox proportional hazards models, and the incremental value of predictors was evaluated with both the C-statistic and the integrated discrimination improvement (IDI) index.

RESULTS

Total mortality was 11% at 2-year follow-up and 65% at an average of 6.6-year of follow-up (maximum, 11.4 years). At 2 years, hs-CRP was a strong and significant predictor of mortality, with a hazard ratio (HR) of 1.56 per standard deviation (P = .006). However, at full follow up, standard CVD risk markers were significant (age, gender, ankle-brachial index, other CVD, and hypertension), but hs-CRP no longer showed a significant relationship (HR 1.12; P = .11). None of the other biomarkers studied showed a significant independent association with mortality. Hs-CRP improved the C-statistic and the IDI beyond standard risk markers at 2 years, but not at full follow-up.

CONCLUSIONS

hs-CRP was a strong predictor of short-term mortality in this cohort of PAD patients, while standard risk markers were better at predicting longer-term mortality.

The association between elevated ankle systolic pressures and peripheral occlusive arterial disease in diabetic and nondiabetic subjects

OBJECTIVE

The presence of a high ankle-brachial index (ABI) is related to stiff ankle arteries due to medial calcification. Recently, this condition has attracted new interest after reports of a worse cardiovascular prognosis, similar to a low ABI. We sought to compare risk factors contributing to a low (< or =0.90) and high (> or =1.40) ABI. Additionally, we hypothesized that in instances of high ABI, occlusive PAD may coexist.

METHOD

This cross-sectional study was conducted at vascular laboratories in a university medical center. The subjects were 510 ambulatory patients (37% had diabetes) previously examined at our vascular laboratories and who responded positively to our invitation. We collected data on smoking, diabetes, hypertension, dyslipidemia, and cardiovascular disease history. The noninvasive assessment of lower limb arteries consisted of the measurement of ABI, toe-brachial index (TBI), and posterior tibial artery peak flow velocity (Pk-PT). A TBI >0.7 and a Pk-PT >10 cm/s were considered normal.

RESULTS

High- and low-ABI were detected, respectively, in 2.1% and 57.8% of limbs. For a low ABI, age (odds ratio [OR], 1.29/10 y), pack-years (OR, 1.08/10 units), and hypertension (OR, 1.90) were independent significant (P < .001) factors. A strong association was found between diabetes and high ABI (OR, 16.0; P < .001). When ABI ranges were compared with TBI and Pk-PT results, those with ABI < or =0.90 and ABI > or =1.40 presented similar patterns of abnormalities. Pk-PT or TBI, or both, was abnormal in more than 80% of cases in both ABI < or =0.90 and > or =1.40 groups. The ABI vs TBI relationship appeared linear in nondiabetic patients, but had an inverted J-shape in diabetic patients, suggesting high ABI masked leg ischemia.

CONCLUSIONS

Diabetes is the dominant risk factor for a high (> or =1.40) ABI. Occlusive PAD is highly prevalent in subjects with high ABI, and these subjects should be considered as PAD-equivalent.

The association between lipoprotein-associated phospholipase A2 and cardiovascular disease and total mortality in vascular medicine patients

INTRODUCTION

In some community-based studies, lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has been shown to be independently predictive of future fatal and nonfatal cardiovascular disease (CVD) events. We tested the hypothesis that Lp-PLA(2) is independently predictive of mortality in high-risk patients from a vascular laboratory.

METHODS

Between 1990 and 1994, patients seen in the previous 10 years for noninvasive lower extremity arterial testing were invited to return for a vascular examination of the lower extremities. By medical record review, we identified 2265 eligible patients; of these, 508 returned for interviews, blood collection, and arterial examination and represent those who had survived, could be located, and were willing to participate. The 508 subjects were followed up for an average of 6.7 years until the end of the study period on December 31, 2001. Vital status was ascertained by multiple searches of the Social Security Death Index. The primary outcomes for this study were time to any, CVD, and coronary heart disease (CHD) mortality.

RESULTS

The mean age was 68.2 years, 88% were men, 87% were non-Hispanic white, 39.1% were diagnosed with peripheral arterial disease only, 9.2% with other CVD only, and 28.5% with both peripheral arterial disease and other CVD. During the entire follow-up period, 299 (59.7%) patients died, 167 from CVD, of which 88 deaths were due to coronary heart disease. With adjustment for CVD risk factors and baseline peripheral arterial disease and other CVD, an increment of one standard deviation in Lp-PLA(2) activity was associated with a 40% higher risk for CHD mortality at 5 years of follow-up (P = .04). Additional adjustment for triglycerides, high-density lipoprotein, and low-density lipoprotein cholesterol reduced this association to nonsignificance (hazard risk, 1.12).

CONCLUSION

In a vascular laboratory patient population, higher levels of LpPLA(2) mass and activity were not significantly associated with total, CVD, or CHD mortality at 5 years of follow-up and after adjustment for traditional CVD risk factors and the presence of PAD and other CVD at baseline. An apparent elevated risk of CHD death associated with elevated Lp-PLA2 was largely explained by associated elevations in lipids and lipoproteins.

Risk factors for chronic venous disease: the San Diego Population Study

BACKGROUND

The etiology of chronic venous disease in the lower limbs is unclear, and very limited data are available on potential risk factors from representative population studies.

METHODS

Participants in the San Diego Population Study, a free-living adult population randomly selected from age, sex, and ethnic strata, were systematically assessed for risk factors for venous disease. Categorization of normal, moderate, and severe disease was determined hierarchically through clinical examination and ultrasonography imaging by trained vascular technologists, who also performed anthropometric measures. An interviewer administered a questionnaire and an examination assessed potential risk factors for venous disease suggested by previous reports.

RESULTS

In multivariable models, moderate venous disease was independently related to age, a family history of venous disease, previous hernia surgery, and normotension in both sexes. In men, current walking, the absence of cardiovascular disease, and not moving after sitting were also predictive. Additional predictors in women were weight, number of births, oophorectomy, flat feet, and not sitting. For severe disease, age, family history of venous disease, waist circumference, and flat feet were predictive in both sexes. In men, occupation as a laborer, cigarette smoking, and normotension were also independently associated with severe venous disease. Additional significant and independent predictors in women were hours standing, history of leg injury, number of births, and cardiovascular disease, but African American ethnicity was protective. Multiple other postulated risk factors for venous disease were not significant in multivariable analysis in this population.

CONCLUSIONS

Although some risk factors for venous disease such as age, family history of venous disease, and findings suggestive of ligamentous laxity (hernia surgery, flat feet) are immutable, others can be modified, such as weight, physical activity, and cigarette smoking. Overall, these data provide modest support for the potential of behavioral risk-factor modification to prevent chronic venous disease.

Ethnic-specific prevalence of peripheral arterial disease in the United States

BACKGROUND

Individuals diagnosed with peripheral arterial disease (PAD) are at increased risk for future functional limitations as well as cardiovascular morbidity and mortality. The aim of this study was to estimate the age-, gender-, and ethnic-specific burden of PAD in the United States for the year 2000.

METHODS

Data were collected from seven community-based studies that assessed subjects for the presence of PAD using the ankle-brachial index (ABI). Using standardized weighting criteria, age-, gender-, and ethnic-specific prevalence rates were computed and then multiplied by the corresponding 2000 Census population totals to estimate the burden of PAD in the United States for that year. Evidence-based adjustments for studies which did not consider possible subclavian stenosis, prior revascularization for PAD, or both were employed.

RESULTS

In 2000, it is conservatively estimated that at least 6.8 million (5.8%) individuals aged 40 years or older had PAD based on an ABI of less than 0.9 or previous revascularization for PAD, and that that there are an additional 1.7 million Americans with PAD but "normal" ABIs. Including this group gives a total of 8.5 million (7.2%) individuals with PAD.

CONCLUSIONS

Roughly one in 16 individuals residing in the United States in 2000 who were aged 40 years and older had PAD. Clinicians are encouraged to screen for the presence of PAD using the ABI.

The vital prognosis of subclavian stenosis

OBJECTIVES

This study sought to assess the prognosis of subclavian stenosis (SS) as a potential marker of total and cardiovascular disease (CVD) mortality.

BACKGROUND

Subclavian stenosis, diagnosed by a brachial systolic pressure difference (BSPD) > or =15 mm Hg, is associated with an increased prevalence of CVD risk factors. However, the association between SS and mortality is unknown. We hypothesized that a BSPD > or =15 mm Hg would predict an increased risk of CVD events.

METHODS

We analyzed baseline and longitudinal data from 3 cohorts. Two were recruited from noninvasive vascular laboratories, and the third was a community-dwelling cohort. Multivariate survival models were used to test for an independent association of SS with total and CVD mortality.

RESULTS

Baseline and follow-up data (mean 9.8 years) were complete in 1,778 participants. Subclavian stenosis was found in 157 (8.8%) subjects. Adjusted for age, gender, ethnicity, and cohort of origin, the presence of SS was significantly associated with increased total and CVD mortality (respectively, hazard ratio [HR] 1.42, p < 0.005; and HR 1.50, p = 0.05). This association persisted after adjustments for CVD risk factors (smoking pack-years, hypertension, diabetes, total/high-density lipoprotein cholesterol ratio, and body mass index) as well as lipid-lowering and antiplatelet therapies (HR 1.40, p < 0.01; and HR 1.57, p < 0.05 for total and CVD mortality, respectively). When any history of CVD or an ankle-brachial index <0.90 were added to the model, SS remained an independent predictor for total mortality (HR 1.34, p = 0.02), with a similar trend for CVD mortality (HR 1.43, p = 0.09).

CONCLUSIONS

The presence of SS, easily diagnosed by comparing systolic pressures in the left and right arm, predicts total and CVD mortality independent of both CVD risk factors and existent CVD at baseline.

Risk factors for progression of peripheral arterial disease in large and small vessels

BACKGROUND

Data on the natural history of peripheral arterial disease (PAD) are scarce and are focused primarily on clinical symptoms. Using noninvasive tests, we assessed the role of traditional and novel risk factors on PAD progression. We hypothesized that the risk factors for large-vessel PAD (LV-PAD) progression might differ from small-vessel PAD (SV-PAD).

METHODS AND RESULTS

Between 1990 and 1994, patients seen during the prior 10 years in our vascular laboratories were invited for a new vascular examination. The first assessment provided baseline data, with follow-up data obtained at this study. The highest decile of decline was considered major progression, which was a -0.30 ankle brachial index decrease for LV-PAD and a -0.27 toe brachial index decrease for SV-PAD progression. In addition to traditional risk factors, the roles of high-sensitivity C-reactive protein, serum amyloid-A, lipoprotein(a), and homocysteine were assessed. Over the average follow-up interval of 4.6+/-2.5 years, the 403 patients showed a significant ankle brachial index and toe brachial index deterioration. In multivariable analysis, current smoking, ratio of total to HDL cholesterol, lipoprotein(a), and high-sensitivity C-reactive protein were related to LV-PAD progression, whereas only diabetes was associated with SV-PAD progression.

CONCLUSIONS

Risk factors contribute differentially to the progression of LV-PAD and SV-PAD. Cigarette smoking, lipids, and inflammation contribute to LV-PAD progression, whereas diabetes was the only significant predictor of SV-PAD progression.

Ethnicity and peripheral arterial disease: the San Diego Population Study

BACKGROUND

Previous studies have indicated higher rates of peripheral arterial disease (PAD) in blacks than in non-Hispanic whites (NHWs), with limited information available for Hispanics and Asians. The reason for the PAD excess in blacks is unclear.

METHODS AND RESULTS

Ethnic-specific PAD prevalence rates were determined in a randomly selected defined population that included 4 ethnic groups; NHWs, blacks, Hispanics, and Asians. A total of 2343 participants aged 29 to 91 years were evaluated. There were 104 cases of PAD (4.4%). In weighted logistic models with NHWs as the reference group and containing demographic factors only, blacks had a higher PAD prevalence than NHWs (OR=2.30, P<0.024), whereas PAD rates in Hispanics and Asians, although somewhat lower, were not significantly different from NHWs. Blacks had significantly more diabetes and hypertension than NHWs and a significantly higher body mass index. Inclusion of these variables and other PAD risk factors in the model did not change the effect size for black ethnicity (OR=2.34, P=0.048). A model containing interaction terms for black ethnicity and each of the other risk factors revealed no significant interaction terms, which indicates no evidence that blacks were more "susceptible" than NHWs to cardiovascular disease risk factors.

CONCLUSIONS

Black ethnicity was a strong and independent risk factor for PAD, which was not explained by higher levels of diabetes, hypertension, and body mass index. There was no evidence of a greater susceptibility of blacks to cardiovascular disease risk factors as a reason for their higher PAD prevalence. Thus, the excess risk of PAD in blacks remains unexplained and requires further study.

Exertional leg pain in patients with and without peripheral arterial disease

BACKGROUND

Although exertional leg pain is a hallmark of peripheral arterial disease (PAD) and can occur in persons without PAD, symptom variation has received inadequate attention.

METHODS AND RESULTS

Three cohort studies were combined for cross-sectional analysis. The San Diego Claudication Questionnaire assessed exertional leg pain. PAD was defined as ankle brachial index (ABI) < or =0.90 or history of lower-extremity revascularization. Of 3658 subjects, 3629 were analyzed after exclusions. Of these, 24.1% had PAD in 1 or both legs. There was a stepwise decrease in average ABI, from no pain to pain on exertion and rest, noncalf pain, atypical calf pain, and classic claudication (P=0.002). When stratified by PAD, this trend was no longer significant. Legs with ABIs >0.90 and revascularization had pain distributions intermediate between that of normal legs (ABI, 1.00 to 1.39) and legs with ABIs < or =0.90. Compared with normal legs, legs with low-normal (0.91 to 0.99) and high-normal (> or =1.40) ABIs had higher pain rates, suggesting borderline disease and vascular stiffness, respectively. Multivariable logistic regression models showed that ABI was a strong correlate of pain category throughout the ABI range. Independently of ABI, age, male sex, diabetes, smoking history, high body mass index, myocardial infarction, and previous revascularization were all significant correlates of exertional leg pain.

CONCLUSIONS

No category of exertional leg pain was sufficiently sensitive or specific for routine PAD diagnosis. Legs with low-normal and high-normal ABIs appeared to have ischemic leg pain; thus, a "normal ABI" is likely to range from 1.00 to 1.39. In addition to ABI, several risk variables were independent correlates of exertional leg pain.

Relationships between symptoms and venous disease: the San Diego population study

BACKGROUND

The associations between symptoms and venous disease of the lower extremities are poorly characterized.

METHODS

We conducted a cross-sectional study to evaluate relationships between symptoms associated with venous disease and prevalent disease in 2408 men and women aged 29 to 91 years who were employees, retirees, or spouses at a large state university. Index participants were randomly selected within strata by age, sex, and ethnicity. A structured interview assessed the prevalence of aching, itching, heaviness, tired legs, cramping, swelling, and nighttime restless legs. A comprehensive standardized examination determined the prevalence of visible disease (normal, telangiectasias, varicose veins, and trophic changes) and functional disease (normal, superficial, and deep disease). We related symptoms to disease with attention to modification by sex, ethnicity, and age.

RESULTS

Aching, itching, heaviness, tired legs, cramping, and swelling were related to both superficial and deep functional disease. The same symptoms were related to varicose veins and trophic changes. Swelling and heaviness were related to telangiectatic disease. Except for restless legs and trophic changes, the prevalence of symptoms across each category was greater in women than men. Aching was the most common symptom but was relatively nonspecific. Swelling was the most specific marker for prevalent visible and functional disease. Heaviness and itching also helped to distinguish prevalent disease.

CONCLUSIONS

Venous symptoms were more prevalent in study participants with both visible and functional disease and in women. Swelling was the most specific predictor; heaviness, itching, and aching also helped to distinguish cases.

Subclavian Artery Stenosis: Prevalence, Risk Factors, and Association With Cardiovascular Diseases

OBJECTIVES

The objective was to assess the prevalence of subclavian artery stenosis (SS) in four cohorts (two free-living and two clinical populations) and determine both risk factors for this condition and the association with other cardiovascular conditions.

BACKGROUND

The prevalence of SS in the general population is unknown, and its association with risk factors and other cardiovascular diseases is not well-established.

METHODS

A total of 4,223 subjects (2,975 from two free-living cohorts and 1,248 from two clinical cohorts) were included in this cross-sectional analysis. Subclavian artery stenosis was defined as > or =15 mm Hg interarm pressure difference.

RESULTS

The prevalence of SS was 1.9% in the free-living cohorts and 7.1% in the clinical cohorts; SS was significantly (p < 0.05) associated with past smoking (odds ratio [OR] = 1.80), current smoking (OR = 2.61), and higher levels of systolic blood pressure (OR = 1.90 per 20 mm Hg). Higher levels of high-density lipoprotein (HDL) cholesterol were inversely and significantly associated with SS (OR = 0.87 per 10 mg/dl). In regression analyses relating SS to other cardiovascular diseases, the only significant finding was with peripheral arterial disease (PAD) (OR = 5.11, p < 0.001).

CONCLUSIONS

Significant SS is present in approximately 2% of the free-living population and 7% of the clinical population. Additionally, SS is correlated with current and past smoking histories, systolic blood pressure, HDL levels (inversely), and the presence of PAD. These findings suggest that bilateral brachial blood pressure measurements should routinely be performed in patients with an elevated risk profile, both to screen for SS, and to avoid missing a hypertension or PAD diagnosis because of unilateral pressure measurement in an obstructed arm.

Chronic venous disease in an ethnically diverse population: the San Diego Population Study

In a 1994-1998 cross-sectional study of a multiethnic sample of 2,211 men and women in San Diego, California, the authors estimated prevalence of the major manifestations of chronic venous disease: spider veins, varicose veins, trophic changes, and edema by visual inspection; superficial and deep functional disease (reflux or obstruction) by duplex ultrasonography; and venous thrombotic events based on history. Venous disease increased with age, and, compared with Hispanics, African Americans, and Asians, non-Hispanic Whites had more disease. Spider veins, varicose veins, superficial functional disease, and superficial thrombotic events were more common in women than men (odds ratio (OR) = 5.4, OR = 2.2, OR = 1.9, and OR = 1.9, respectively; p < 0.05), but trophic changes and deep functional disease were less common in women (OR = 0.7 for both; p < 0.05). Visible (varicose veins or trophic changes) and functional (superficial or deep) disease were closely linked; 92.0% of legs were concordant and 8.0% discordant. For legs evidencing both trophic changes and deep functional disease, the age-adjusted prevalences of edema, superficial events, and deep events were 48.2%, 11.3%, and 24.6%, respectively, compared with 1.7%, 0.6%, and 1.3% for legs visibly and functionally normal. However, visible disease did not invariably predict functional disease, or vice versa, and venous thrombotic events occurred in the absence of either.

Quality of life in patients with chronic venous disease: San Diego population study

BACKGROUND

Chronic venous disease in the lower extremities may have a substantial effect on functioning and quality of life. We report quality of life data for an ethnically diverse population that had been systematically evaluated for venous disease.

SUBJECTS

Current and retired employees from a large public university were randomly selected within strata of age, sex, and ethnicity. The sample included 2404 men and women ages 40 to 79 years.

MEASURES

Quality of life was measured with the Medical Outcomes Study 36-Item Short Form (SF-36). Venous disease of the lower extremities was evaluated with two methods. Visual inspection was used to place participants into four categories: normal, telangiectasias and spider veins, varicose veins, and trophic changes. Duplex ultrasound scanning was used to place participants into three categories: normal, superficial venous disease, and deep vein disease.

RESULTS

There were significant associations between quality of life and venous disease severity as assessed with both visual and ultrasound methods. These differences were observed for both men and women for functional scales of the SF-36. The relationships were significant, and were graded with degree of disease severity. Differences categories were not statistically significant for the mental health scales of the SF-36.

CONCLUSION

Chronic venous disease in the lower extremities has a substantial effect on physical health aspects of quality of life but not on mental health components.

Quantified duplex augmentation in healthy subjects and patients with venous disease: San Diego population study

OBJECTIVE

This study was undertaken to determine the quantitative augmentation response in several veins examined in a cohort assembled to permit comparisons by sex, age, and ethnicity, under normal conditions and in the presence of obstruction, with and without trophic changes.

METHOD

The common femoral vein, superficial femoral vein, sapheno-femoral junction, popliteal vein, sapheno-popliteal junction, and posterior tibial vein were studied with duplex ultrasonographic scanning. Augmentation response was elicited with use of an automated cuff inflator. Mean level of each response was analyzed according to patient sex, age, and ethnicity, each adjusted for the other two. Normal values were compared with those obtained from legs with venous obstructive disease, with or without signs of trophic changes.

RESULTS

Decreased augmentation response was noted only in the sapheno-femoral junction and sapheno-popliteal junction, and was smaller in women. Augmentation response was slightly increased in the oldest age group (>70 years) in the common femoral vein, superficial femoral vein, popliteal vein, and posterior tibial vein. The highest augmentation response was found in Asian subjects, in the common and superficial femoral veins and the sapheno-femoral and sapheno-popliteal junctions; and the smallest augmentation response was found in African American subjects, in these same veins and junctions. Differences in vein diameters may explain these findings, ie, smaller diameters in Asians and larger diameters in African Americans. Most important, compared with normal values, augmentation response was decreased in legs with venous obstructive disease only when trophic changes were present.

CONCLUSION

Like quantification of reflux, quantitative evaluation of the augmentation response may help in diagnosis of venous obstructive disease when trophic changes are present.

The correlation between the severity of peripheral arterial disease and carotid occlusive disease

Peripheral arterial disease (PAD) and carotid occlusive disease (COD) are both known to be specific manifestations of atherosclerosis. Because they both have a common cause, it is reasonable to hypothesize that they should correlate with each other to a certain extent, and previous studies have shown that there is a correlation between the prevalence of PAD and COD. The purpose of this study was to determine whether a correlation exists between the severity of PAD and the severity of COD by retrospectively looking at a group of 203 patients who underwent non-invasive testing for suspicion of PAD at the San Diego VA Hospital or UCSD Medical Center, and who also had a non-invasive duplex carotid scan. The severity of PAD was assessed by segmental blood pressure ratios (leg segment/arm ratio) in each leg taken at the toe, ankle, and below the knee, as well as the peak flow velocity of the posterior tibial artery. The severity of COD was assessed by duplex ultrasound scans of six distinct segments of the carotid artery system: the right and left common, internal, and external carotid arteries. Correlation analysis showed r=0.23 (p=0.001) when comparing a PAD aggregate standard score with the number of diseased carotid arteries (>50% stenosis), and r=0.23 (p=0.001) when comparing a PAD aggregate standard score with an average COD score. Because about 50% of the patients had undergone surgical intervention on their leg or carotid arteries, another correlation analysis restricted to patients with no surgical interventions (n = 97) was performed. The above correlations were slightly attenuated in this analysis, r=0.21 (p=0.043) and r=0.17 (p= 0.092), respectively. The results indicate that there is a modest but significant correlation between the severity of PAD and the severity of COD in a population with a high prevalence of both.

Quantitative and qualitative progression of peripheral arterial disease by non-invasive testing

There is little information on the progression of peripheral arterial disease (PAD) over time. A series of 508 patients with a prior examination for PAD were contacted and brought in for follow-up to evaluate the natural history of PAD. A total of 85 patients were excluded because they had interventions in both limbs prior to their return visit. Progression was assessed in the remaining 423 patients for a total of 755 limbs, both quantitatively and qualitatively using six categories of PAD severity. There was a modest overall categorical progression of disease: 228 limbs (30.2%) displayed categorical progression, while 172 limbs (22.8%) improved over a 4.6-year average follow-up. Through analysis of quantitative change, it was determined that more quantitative progression occurred than was evident from categorical progression. Two of the three non-invasive tests employed, the ankle/brachial index (ABI) and posterior tibial peak forward flow velocity (peak PT), showed statistically significant progression during follow-up: mean ABI change = -0.019, 95% confidence interval (CI)= -0.031 to -0.007; mean peak PT change = -2.32 cm/s, 95% CI = -3.20 to -1.44. The toe/brachial index (TBI) also suggested progression: mean change= -0.013, but the 95% CI included no change. Standard scores (sum of the Z-scores for ABI, peak PT and TBI) were calculated. The standard score progressed approximately 0.34 units (standard deviations), p-value <0.001, over 4.6 years; or about 0.07 standard deviations per year. There were independent and statistically significant (p<0.05) associations between the rate of PAD progression (standard score change) and age, diabetes, classic ('Rose') intermittent claudication, moderate to severe PAD in the same limb, moderate to severe PAD in the contralateral limb and future therapeutic intervention. There were independent and suggestive associations (0.05<p-value<0.15) between PAD progression and pain at rest, mild PAD in the same limb, and mild PAD in the contralateral limb. PAD progression was not associated with gender, atypical claudication, or amputation status. Thus, in this cohort of PAD patients, PAD on average progressed significantly over 4.6 years. This progression was independently related to age, diabetes and several markers of disease severity.

The generalized nature of atherosclerosis: how peripheral arterial disease may predict adverse events from coronary artery disease

Non-invasive measurements, especially segmental pressure ratios and flow measurements, are useful for gauging the severity of peripheral arterial disease (PAD). Although the incidence of PAD is similar for men and women, men are more likely to have severe disease, while women usually have more moderate or asymptomatic disease. Published reports confirm the clinical impression that patients with PAD are more likely to have both coronary artery disease and cerebrovascular disease than those without PAD. However, the degree of overlap is a function of the sensitivity of the diagnostic assessments for the three conditions. A San Diego population study found that the incidence of PAD may be underestimated, with many patients being asymptomatic. Based on blood flow measurements, the study found that 11.9% of the study population had large vessel PAD. Morbidity from both coronary heart disease and stroke was increased in people with PAD, who were 2.5 times more likely to present with morbidity from cardiovascular disease (CVD) than those who did not have PAD. Several studies have now confirmed the strong predictive value of PAD for subsequent CVD mortality and that the risk of CVD mortality increases with the severity of PAD.

The epidemiology of peripheral arterial disease: importance of identifying the population at risk

Data from the Framingham Study and other population studies indicate that intermittent claudication (IC) sharply increases in late middle age and is somewhat higher among men than women. Noninvasive testing in populations indicates that the true prevalence of peripheral arterial disease (PAD) is at least five times higher than would be expected based on the reported prevalence of IC. Peripheral arterial disease correlates most strongly with cigarette smoking and either diabetes or impaired glucose tolerance. Other risk factors for PAD include hypertension; low levels of high-density lipoprotein cholesterol; and high levels of triglycerides, apolipoprotein B, lipoprotein(a), homocysteine, fibrinogen and blood viscosity. Individuals with PAD are more likely to have coronary heart disease and cerebrovascular disease than those without PAD. Because of the high risk of both nonfatal and fatal cardiovascular disease (CVD) events in PAD patients, individuals with evidence of PAD should undergo both a careful examination of the entire cardiovascular system and aggressive modification of CVD risk factors.

The correlation between symptoms and non-invasive test results in patients referred for peripheral arterial disease testing

The WHO/Rose questionnaire has served as the epidemiologic and clinical standard in the assessment of leg pain in patients with peripheral arterial disease (PAD) for over three decades. However, the structure of this questionnaire does not allow assessment of leg-specific (i.e. right versus left) symptoms. We studied 508 patients aged 39-95 years (mean 68 years), initially referred for PAD non-invasive testing. A revised questionnaire, the San Diego Claudication Questionnaire, was administered which allowed determination of leg-specific symptoms and evaluated thigh and buttock as well as calf pain. Leg-specific symptoms were categorized into no pain, pain at rest, non-calf claudication, non-Rose calf claudication, and Rose claudication. At the same visit, the ankle brachial index, the toe brachial index, and peak posterior tibial flow velocity were measured by Doppler ultrasound and five categories of non-invasive results by type and severity of PAD were defined. Legs with previous intervention (Rx), surgery or angioplasty, were evaluated separately. Claudication was reported in 42% of no Rx legs and 50% of Rx legs; 40% of claudication was atypical (not Rose); 64% of no Rx and 81% of Rx legs had PAD by non-invasive testing, and 27% of affected legs had severe PAD. The correlation between the severity of symptoms and the severity of ipsilateral PAD in no Rx legs was r = -0.40, p < 0.001. In Rx legs, this correlation was somewhat less (r = 0.27, p < 0.001) due to more symptomatology at lesser degrees of PAD, suggesting reporting bias and/or more residual disease than evident from non-invasive testing. To our knowledge, these results provide the first comparison between a standardized assessment of leg pain and the severity of ipsilateral PAD by non-invasive testing.

Corpus callosum: region-specific effects of sex, early experience and age

In infancy, rats were provided handling stimulation and compared at 110 and 215 days of age with non-handled controls. Measurements were made of corpus callosum area, perimeter and length; and width measures were taken at 7 points along the longitudinal axis of the callosum. Callosal size was larger in males than in females, even when adjusted for the larger brain weight of the male. At 110 days handling stimulation increased callosal parameters and resulted in a more regular callosum in males, but this effect was no longer apparent by 215 days. Within the callosum, region-specific effects were found, suggesting that certain callosal fiber populations were involved. Handled males have previously been shown to be more lateralized than non-handled males; thus at least in this experimental system, increased callosal size and regularity is associated with greater hemispheric specialization.