Comparing coronary artery cross-sectional area among asymptomatic South Asian, White, and Black participants: the MASALA and CARDIA studies

BACKGROUND

South Asian individuals have high risk of atherosclerotic cardiovascular disease (ASCVD). Some investigators suggest smaller coronary artery size may be partially responsible.

METHODS

We compared the left anterior descending (LAD) artery cross-sectional area (CSA) (lumen and arterial wall) among South Asians in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study with White and Black participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study, adjusting for BMI, height, and other ASCVD risk factors. We used thin-slice non-contrast cardiac computed tomography to measure LAD CSA. We used linear regression models to determine whether race/ethnicity was associated with LAD CSA after adjusting for demographic factors, BMI, height, coronary artery calcium (CAC), and traditional cardiovascular risk factors.

RESULTS

Our sample included 3,353 participants: 513 self-identified as South Asian (44.4% women), 1286 as Black (59.6% women), and 1554 as White (53.5% women). After adjusting for age, BMI, height, there was no difference in LAD CSA between South Asian men and women compared to White men and women, respectively. After full adjustment for CVD risk factors, LAD CSA values were: South Asian women (19.9 mm2, 95% CI [18.8 - 20.9]) and men (22.3 mm2, 95% CI [21.4 - 23.2]; White women (20.0 mm2, 95% CI [19.4-20.5]) and men (23.6 mm2, 95% CI [23.0-24.2]); and Black women (21.6 mm2, 95% CI [21.0 - 22.2]) and men (26.0 mm2, 95% CI [25.3 - 26.7]). Height, BMI, hypertension, CAC, and age were positively associated with LAD CSA; current and former cigarette use were inversely associated.

CONCLUSIONS

South Asian men and women have similar LAD CSA to White men and women, and smaller LAD CSA compared to Black men and women, respectively, after accounting for differences in body size. Future studies should determine whether LAD CSA is associated with future ASCVD events.

Type 2 Diabetes Modifies the Association of CAD Genomic Risk Variants With Subclinical Atherosclerosis

BACKGROUND

Individuals with type 2 diabetes (T2D) have an increased risk of coronary artery disease (CAD), but questions remain about the underlying pathology. Identifying which CAD loci are modified by T2D in the development of subclinical atherosclerosis (coronary artery calcification [CAC], carotid intima-media thickness, or carotid plaque) may improve our understanding of the mechanisms leading to the increased CAD in T2D.

METHODS

We compared the common and rare variant associations of known CAD loci from the literature on CAC, carotid intima-media thickness, and carotid plaque in up to 29 670 participants, including up to 24 157 normoglycemic controls and 5513 T2D cases leveraging whole-genome sequencing data from the Trans-Omics for Precision Medicine program. We included first-order T2D interaction terms in each model to determine whether CAD loci were modified by T2D. The genetic main and interaction effects were assessed using a joint test to determine whether a CAD variant, or gene-based rare variant set, was associated with the respective subclinical atherosclerosis measures and then further determined whether these loci had a significant interaction test.

RESULTS

Using a Bonferroni-corrected significance threshold of P<1.6×10-4, we identified 3 genes (ATP1B1, ARVCF, and LIPG) associated with CAC and 2 genes (ABCG8 and EIF2B2) associated with carotid intima-media thickness and carotid plaque, respectively, through gene-based rare variant set analysis. Both ATP1B1 and ARVCF also had significantly different associations for CAC in T2D cases versus controls. No significant interaction tests were identified through the candidate single-variant analysis.

CONCLUSIONS

These results highlight T2D as an important modifier of rare variant associations in CAD loci with CAC.

Long-term aspartame and saccharin intakes are related to greater volumes of visceral, intermuscular, and subcutaneous adipose tissue: the CARDIA study

BACKGROUND

Artificial sweetener (ArtSw) intakes have been previously associated with higher BMI in observational studies and may promote visceral and skeletal muscle adipose tissue (AT) accumulation. This study aimed to determine whether habitual, long-term ArtSw or diet beverage intakes are related to greater AT depot volumes and anthropometry-related outcomes.

METHODS

A validated diet history questionnaire was administered at baseline, year 7, and year 20 examinations in 3088 men and women enrolled in the Coronary Artery Risk Development in Young Adults cohort (CARDIA), mean age of 25.2 years and mean BMI of 24.5 kg/m2 at baseline. Volumes of visceral (VAT), intermuscular (IMAT), and subcutaneous adipose tissue (SAT) were assessed by computed tomography at year 25. Linear regression evaluated associations of aspartame, saccharin, sucralose, total ArtSw, and diet beverage intakes with AT volumes, anthropometric measures, and 25-year change in anthropometry. Cox regression estimated associations of ArtSw with obesity incidence. Adjustments were made for demographic and lifestyle factors, total energy intake, and the 2015 healthy eating index.

RESULTS

Total ArtSw, aspartame, saccharin, and diet beverage intakes were positively associated with VAT, SAT, and IMAT volumes (all ptrend ≤ 0.001), but no associations were observed for sucralose intake (all ptrend > 0.05). In addition, total ArtSw, saccharin, aspartame, and diet beverage intakes were associated with greater body mass index, body weight, waist circumference, and their increases over a 25-year period. Except for saccharin (ptrend = 0.13), ArtSw, including diet soda, was associated with greater risks of incident obesity over a median 17.5-year follow-up (all ptrend < 0.05).

CONCLUSIONS

Results suggest that long-term intakes of aspartame, saccharin, or diet soda may increase AT deposition and risk of incident obesity independent of diet quality or caloric intake. Coupled with previous evidence, alternatives to national recommendations to replace added sugar with ArtSw should be considered since both may have health consequences.

Mitral annular calcification as a predictor of stroke in the multiethnic study of atherosclerosis

BACKGROUND

Mitral annular calcification (MAC) is associated with an increased risk for cardiovascular morbidity and mortality. This study provides recent data on the association between cardiac computed tomography (CT) derived MAC and 15 years of stroke risk in a racially diverse cohort.

METHODS

All multiethnic studies of atherosclerosis participants ( n  = 6814) who completed a cardiac CT at baseline were included in this analysis. MAC score was calculated from cardiac CT using the Agatston and volume score methods. Multivariable Cox proportional hazard regression models were used to compute hazard ratios for the association between MAC and stroke after adjusting for traditional cardiovascular risk factors, inflammatory markers, coronary artery calcium score, atrial fibrillation, and left atrial size.

RESULTS

Overall, 9% of participants (644/6814) had MAC at baseline. Over a surveillance period of 15 years, 304 strokes occurred, and 79% were ischemic strokes. After adjusting for age, sex, race/ethnicity, SBP, diabetes, smoking, fibrinogen, IL-6, high-sensitivity C-reactive protein, and coronary artery calcium score, baseline MAC was associated with increased risk for all strokes [hazard ratio 1.68; 95% confidence interval (CI) 1.22-2.30: P  = 0.0013]. When atrial fibrillation/flutter and left atrial size were included in the final multivariable model, MAC remained a predictor of all strokes (hazard ratio 1.93; 95% CI 1.22-3.05: P  < 0.0051) and ischemic stroke (hazard ratio 2.03; 95% CI 1.24-3.31: P  < 0.0046).

CONCLUSION

MAC is an independent predictor of long-term stroke risk in a racially diverse population beyond conventional cardiovascular risk factors and atrial fibrillation.

Association of Abdominal Aorta Calcium and Coronary Artery Calcium with Incident Cardiovascular and Coronary Heart Disease Events in Black and White Middle-Aged People: The Coronary Artery Risk Development in Young Adults Study

Background Assessing coronary artery calcium (CAC) is among AHA/ACC prevention guidelines for people at least 40 years old at intermediate risk for coronary heart disease (CHD). To study enhanced risk stratification, we investigated the predictive value of abdominal aorta calcium (AAC) relative to CAC for cardiovascular disease (CVD) and CHD events in Black and White early middle-aged participants, initially free of overt CVD. Methods and Results In the CARDIA (Coronary Artery Risk Development in Young Adults) study, a multi-center, community-based, longitudinal cohort study of CVD risk, the CAC and AAC scores were assessed in 3011 participants in 2010-2011 with follow-up until 2019 for incident CVD and CHD events. Distributions and predictions, overall and by race, were computed. During the 8-year follow-up, 106 incident CVD events (55 were CHD) occurred. AAC scores tended to be much higher than CAC scores. AAC scores were higher in Black women than in White women. CAC predicted CVD with HR 1.77 (1.52-2.06) and similarly for AAC, while only CAC predicted CHD. After adjustment for risk factors and calcium in the other arterial bed, the association of CAC with CVD was independent of risk factors and AAC, while the association of AAC with CVD was greatly attenuated. However, AAC predicted incident CVD when CAC was 0. Prediction did not vary by race. Conclusions AAC predicted CVD nearly as strongly as CAC and could be especially useful as a diagnostic tool when it is an incidental finding or when no CAC is found.

Abstract 071: Ten-year Change In Tv Viewing Is Associated With Concurrent Change In Pericardial Adipose Tissue In Middle-aged Adults: The Coronary Artery Risk Development In Young Adults (CARDIA) Study

Introduction: Pericardial adipose tissue (PAT), an ectopic adipose depot surrounding the coronary arteries, is a pathogenic risk factor for cardiometabolic disease; however, the association of sedentary behavior with PAT is poorly understood. We examined the longitudinal association of 10-year change in TV viewing with concurrent change in PAT.

Hypothesis: Increased h/day of TV viewing over 10 years are associated with larger mean increases in PAT during the same 10-year period.

Methods: Middle-aged adults (N=1659, mean age=40.4, 912 females, 733 blacks) from the Coronary Artery Risk Development in Young Adults (CARDIA) Study at the exam years 15 (2000-2001) and 25 (2010-2011) were included. Both TV viewing (h/day) and the volume of PAT (mL) were measured at Years 15 and 25 using the CARDIA physical activity questionnaire and computed tomography, respectively. Covariates measured at year 15 included PAT, sociodemographic factors, cardiovascular disease risk factors, diet quality, TV viewing, moderate-to-vigorous intensity physical activity (MVPA), inflammatory cytokines, and waist circumference. Multivariable linear regression was used to estimate 10-year change in PAT across increasing tertiles (≤ -1, > -1 to < 1, ≥ 1 h/day) of 10-year changes in TV viewing.

Results: On average, TV viewing and PAT increased between the two exam years by 0.2 h/day (8.7% increase, mean: 2.3 → 2.5 h/day) and 11.8 mL (25.9% increase, mean: 45.6 → 57.4 mL), respectively (all p < 0.01). In the fully adjusted model including MVPA and other major confounders, the highest tertile of 10-year change in TV viewing was associated with greater change in PAT (β = 2.97 mL, p < 0.01) when compared with the lowest tertile (see Figure 1 ), while mean PAT change was intermediate in the middle tertile.

Conclusions: A greater 10-year increase in TV viewing is associated with a greater concurrent increase in PAT, independent of MVPA and other important confounders. Reducing TV viewing time may be associated with less PAT accumulation with age.

Prediction of Type II Diabetes Onset with Computed Tomography and Electronic Medical Records

Type II diabetes mellitus (T2DM) is a significant public health concern with multiple known risk factors (e.g., body mass index (BMI), body fat distribution, glucose levels). Improved prediction or prognosis would enable earlier intervention before possibly irreversible damage has occurred. Meanwhile, abdominal computed tomography (CT) is a relatively common imaging technique. Herein, we explore secondary use of the CT imaging data to refine the risk profile of future diagnosis of T2DM. In this work, we delineate quantitative information and imaging slices of patient history to predict onset T2DM retrieved from ICD-9 codes at least one year in the future. Furthermore, we investigate the role of five different types of electronic medical records (EMR), specifically 1) demographics; 2) pancreas volume; 3) visceral/subcutaneous fat volumes in L2 region of interest; 4) abdominal body fat distribution and 5) glucose lab tests in prediction. Next, we build a deep neural network to predict onset T2DM with pancreas imaging slices. Finally, motivated by multi-modal machine learning, we construct a merged framework to combine CT imaging slices with EMR information to refine the prediction. We empirically demonstrate our proposed joint analysis involving images and EMR leads to 4.25% and 6.93% AUC increase in predicting T2DM compared with only using images or EMR. In this study, we used case-control dataset of 997 subjects with CT scans and contextual EMR scores. To the best of our knowledge, this is the first work to show the ability to prognose T2DM using the patients' contextual and imaging history. We believe this study has promising potential for heterogeneous data analysis and multi-modal medical applications.

Added sugar intake is associated with pericardial adipose tissue volume

AIM

The purpose of this study was to determine the relationships of pericardial adipose tissue and visceral adipose tissue volume with added sugar and sugar-sweetened beverage intakes. We hypothesized that both added sugar and sugar-sweetened beverages were positively associated with pericardial adipose tissue and visceral adipose tissue volumes in black and white men and women enrolled in the prospective Coronary Artery Risk Development in Young Adults study.

METHODS AND RESULTS

Dietary intake was assessed by diet history at baseline, year 7 and year 20 examinations in 3070 participants aged 18-30 and generally healthy at baseline. After 25 years follow-up, participants underwent a computed tomography scan of chest and abdomen; the computed tomography scans were read, and pericardial adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue volumes were calculated. Quintiles were created for the average of baseline, year 7 and year 20 added sugar and for the average of sugar-sweetened beverages. General linear regression analysis evaluated the associations of pericardial adipose tissue and visceral adipose tissue volumes across quintiles of added sugar and across quintiles of sugar-sweetened beverage intakes adjusted for potential confounding factors. In a multivariable model, pericardial adipose tissue volume was higher across increasing quintiles of added sugar and sugar-sweetened beverage intakes (p_trend = 0.001 and p_trend < 0.001, respectively). A similar relation was observed for visceral adipose tissue (p_trend < 0.001 for both added sugar and sugar-sweetened beverages).

CONCLUSIONS

Long-term intakes of added sugar and sugar-sweetened beverages were associated with higher pericardial adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue volumes. Because these ectopic fat depots are associated with greater risk of disease incidence, these findings support limiting intakes of added sugar and sugar-sweetened beverages.

The effect of weight loss on the progression of meniscal extrusion and size in knee osteoarthritis: a post-hoc analysis of the Intensive Diet and Exercise for Arthritis (IDEA) trial

OBJECTIVE

Weight loss has beneficial effects on clinical outcomes in knee osteoarthritis (OA), but the mechanism is still unclear. Since meniscus extrusion is associated with knee pain, this study assessed whether weight loss by diet and/or exercise is associated with less progression in meniscus extrusion measures over time.

DESIGN

The Intensive Diet and Exercise for Arthritis trial (IDEA) was a prospective, single-blind, randomized-controlled trial including overweight and obese older adults with knee pain and radiographic OA. Participants were randomized to 18-month interventions: exercise only, diet only or diet + exercise. In a random subsample of 105 participants, MRIs were obtained at baseline and follow-up. The medial and lateral menisci were segmented and quantitative position and size measures were obtained, along with semiquantitative extrusion measures. Linear and log-binomial regression were used to examine the association between change in weight and change in meniscus measures. Between-group differences were analyzed using an analysis of covariance.

RESULTS

Weight loss was associated with less progression over time of medial meniscus extrusion as measured by the maximum (β: -24.59 μm, 95%CI: -41.86, -7.33) and mean (β: -19.08 μm, 95%CI: -36.47, -1.70) extrusion distances. No relationships with weight loss were observed for lateral meniscus position, medial or lateral meniscus size or semiquantitative measures. Change in meniscus position and size did not differ significantly between groups.

CONCLUSIONS

Weight loss was associated with beneficial modifications of medial meniscus extrusion over 18 months. This may be one of the mechanisms by which weight loss translates into a clinical benefit.

CLINICAL TRIAL REGISTRATION

NCT00381290.

Pulmonary Artery Acceleration Time in Young Adulthood and Cardiovascular Outcomes Later in Life: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

Lower pulmonary artery acceleration time (PAcT) is correlated with higher pulmonary artery pressure. The aim of this study was to test the hypothesis that PAcT measured in young adulthood would be associated with future cardiovascular outcomes.

METHODS

In the Coronary Artery Risk Development in Young Adults year 5 examination (1990-1991), PAcT was measured as the time interval from onset to peak flow velocity at the pulmonary valve annulus on Doppler echocardiography. The primary outcome was a composite of fatal or nonfatal cardiovascular disease events: myocardial infarction, non-myocardial infarction acute coronary syndrome, coronary revascularization, congestive heart failure, stroke, transient ischemic attack, carotid artery disease, and peripheral arterial disease.

RESULTS

PAcT was obtained in 4,171 participants (mean age, 30 ± 4 years, 55% women, 51% white). PAcT groups obtained using linear spline methodology were as follows: group I, PAcT ≥ 196 msec (n = 122); group II, PAcT < 196 and ≥115 msec (n = 3,195); and group III, PAcT < 115 msec (n = 854). During follow-up (median, 24.9 years), the primary outcome occurred in 216 participants (5.2%); 66 of 854 (7.7%) of those with PAcT < 115 msec, 149 of 3,195 (4.7%) of those with intermediate PAcT level, and one of 122 (0.8%) of those with PAcT ≥ 196 msec. In a fully adjusted model, the lowest and intermediate PAcT groups had hazard ratios of 8.3 (95% CI, 1.1-62.1; P = .04) and 6.8 (95% CI, 0.9-50.5; P = .06), respectively, in comparison with the highest PAcT group.

CONCLUSIONS

PAcT is useful for better identifying young adults at higher risk for cardiovascular events, who may benefit from a strict control of modifiable cardiovascular risk factors.

Longer lactation duration is associated with decreased prevalence of non-alcoholic fatty liver disease in women

BACKGROUND & AIMS

Lactation lowers blood glucose and triglycerides, and increases insulin sensitivity. We hypothesized that a longer duration of lactation would be associated with lower prevalence of non-alcoholic fatty liver disease (NAFLD), which is the leading cause of chronic liver disease in the United States.

METHODS

Participants from the Coronary Artery Risk Development in Young Adults cohort study who delivered ≥ 1 child post-baseline (Y0: 1985-1986), and underwent CT quantification of hepatic steatosis 25 years following cohort entry (Y25: 2010-2011) were included (n = 844). The duration of lactation was summed for all post-baseline births, and NAFLD at Y25 was assessed by central review of CT images and defined by liver attenuation ≤ 40 Hounsfield Units after exclusion of other causes of hepatic steatosis. Unadjusted and multivariable logistic regression analyses were performed using an a priori set of confounding variables; age, race, education, and baseline body mass index.

RESULTS

Of 844 women who delivered after baseline (48% black, 52% white, mean age 49 years at Y25 exam), 32% reported lactation duration of 0 to 1 month, 25% reported >1 to 6 months, 43% reported more than 6 months, while 54 (6%) had NAFLD. Longer lactation duration was inversely associated with NAFLD in unadjusted logistic regression. For women who reported >6 months lactation compared to those reporting 0-1 month, the odds ratio for NAFLD was 0.48 (95% CI 0.25-0.94; p = 0.03) and the association remained after adjustment for confounders (adjusted odds ratio 0.46; 95% CI 0.22-0.97; p = 0.04).

CONCLUSIONS

A longer duration of lactation, particularly greater than 6 months, is associated with lower odds of NAFLD in mid-life and may represent a modifiable risk factor for NAFLD.

LAY SUMMARY

A longer duration of breastfeeding has been associated with multiple potential health benefits for the mother including reduction in heart disease, diabetes and certain cancers. In this study we found that breastfeeding for longer than 6 months was associated with a lower risk of non-alcoholic fatty liver disease in mid-life.

Police and social workers in a community outreach program

Families who might not apply to a social service agency are interviewed in their homes at a time when denial of the problem is virtually impossible

Associations of osteoprotegerin with coronary artery calcification among women with systemic lupus erythematosus and healthy controls

Objective We tested the hypothesis that higher circulating levels of osteoprotegerin (OPG) are related to higher levels of coronary artery calcification (CAC) among women with systemic lupus erythematosus (SLE) compared with healthy controls (HCs). Methods Among 611 women in two age- and race-matched SLE case-control studies, OPG was assayed in stored blood samples (HEARTS: plasma, n cases/controls = 122/124, and SOLVABLE: serum, n cases/controls = 185/180) and CAC was measured by electron beam computed tomography. Results In both studies, SLE patients had higher OPG and CAC levels than HCs. Higher OPG was associated with high CAC (>100 vs.100) among SLE, and with any CAC (>0 vs. 0) among HCs. Multivariable-adjusted OR (95% CI) for OPG tertile 3 vs. 1 was 3.58 (1.19, 10.76), p trend = 0.01 for SLE, and 2.28 (1.06, 4.89), p trend = 0.04 for HCs. Associations were attenuated when age-adjusted, but remained significant for HC women aged ≥ 40 and SLE women aged ≥ 50. ROC analyses identified 4.60 pmol/l as the optimal OPG cutpoint for predicting high CAC (>100) among SLE patients with sensitivity = 0.74 and specificity = 0.61, overall, but 0.92 and 0.52, respectively, for SLE patients aged ≥ 50. Conclusion Our cross-sectional results suggest that higher OPG levels are related to higher CAC levels among women with SLE vs. healthy controls.

Rapid decline in lung function is temporally associated with greater metabolically active adiposity in a longitudinal study of healthy adults

RATIONALE

Adiposity is associated with low lung function, but the longitudinal relationship between lung function and adiposity is inadequately studied.

OBJECTIVE

To examine the bidirectional longitudinal associations between rapid decline in lung function and adiposity phenotypes in healthy adults.

METHODS

This secondary analysis used a 25-year longitudinal dataset from the Coronary Artery Risk Development in Young Adults (CARDIA) study that enrolled 5115 participants.

MEASUREMENTS

In the first analysis, metabolic syndrome at or before CARDIA year (Y) 10 (Y10) was the predictor, and subsequent rapid decline in forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1) between Y10 and Y20 was the outcome. In the second analysis, rapid decline was the predictor, and incident metabolic syndrome at Y20 and/or Y25 was the outcome. In the third analysis, rapid decline was the predictor, and subsequent CT-assessed regional fat depots at Y25 were the outcome.

RESULTS

Metabolic syndrome at or before Y10 is temporally associated with rapid decline in FVC between Y10 and Y20 (adjusted p=0.04), but this association was explained by body mass index (BMI) at Y10. Rapid decline in FVC or FEV1 is temporally associated with greater incident metabolic syndrome at Y20 and/or Y25 (adjusted OR 2.10 (1.69, 2.61); p<0.001, and 1.56 (1.26, 1.94); p<0.001, respectively) and greater CT-assessed intrathoracic visceral adiposity at Y25 (adjusted standardised β 0.09; p<0.001 for both analyses). These associations were not explained by BMI levels prior to the outcome measurement.

CONCLUSIONS

Healthy adults with rapid decline in lung function are at risk for developing metabolic syndrome and for disproportionate accumulation of intrathoracic visceral fat. Metabolic abnormalities may be an early extrapulmonary manifestation of lung impairment that may be preventable by improving lung health.

Community participation for individuals with spinal cord injury living in Queensland, Australia

STUDY DESIGN

Sequential mixed method design.

OBJECTIVES

Determine factors associated with community participation for individuals with spinal cord injury (SCI).

SETTING

Queensland, Australia.

METHODS

Phase I consisted of a quantitative telephone survey of 270 people who had sustained a SCI within the past 50 years. To verify and interpret survey findings, Phase II involved a qualitative investigation. One focus group, one dyadic and one in-depth interview were conducted with a separate sample of eight people who had sustained a SCI within the past 50 years.

RESULTS

In Phase I, employment, paid or unpaid, was the strongest independent factor associated with community participation, whereas time since injury, completeness of injury, secondary conditions and functional independence were also independently associated. In Phase II, participants expressed that survey findings were consistent with their lived experiences. They explained that overall, they needed a strong reason to participate so that benefits outweigh the effort required to participate. Once out in the community, they recognised that other opportunities for participation arise.

CONCLUSION

Rehabilitation services need to support individuals with SCI to find meaningful employment and to engage in activities that provide them with a strong reason to participate.

Gestational Diabetes Mellitus Is Strongly Associated With Non-Alcoholic Fatty Liver Disease

OBJECTIVES

Insulin resistance is central to the development of non-alcoholic fatty liver disease (NAFLD), and gestational diabetes mellitus (GDM) is an early marker of insulin resistance. We hypothesized that a history of GDM would identify women at higher risk of NAFLD in middle age.

METHODS

Women from the multicenter Coronary Artery Risk Development in Young Adults (CARDIA) cohort study who delivered ≥1 birth, were free of diabetes prior to pregnancy(ies), and underwent CT quantification of hepatic steatosis 25 years following cohort entry (Y25: 2010-2011) were included (n=1,115). History of GDM by self-report, validated in a subsample by review of antenatal glucose testing, and metabolic risk factors were assessed prospectively. NAFLD was defined by liver attenuation (LA)≤40 Hounsfield Units on CT scan after exclusion of other causes of hepatic steatosis.

RESULTS

Of 1,115 women meeting selection criteria (57% black, 43% white, median age 25 years at baseline), 124 (11%) reported a history of GDM and 75 (7%) met the CT definition for NAFLD at year 25. The crude risk of NAFLD at the 25-year visit was significantly higher in women with GDM compared to those without (14 vs. 5.8%, OR: 2.56, 95% CI: 1.44-4.55, P<0.01). History of GDM remained associated with NAFLD (OR: 2.29, 95% CI: 1.23-4.27, P=0.01) after adjustment for covariates in multivariable logistic regression. Addition of incident diabetes mellitus (DM) into the final model attenuated the association between GDM and NAFLD (OR: 1.48, 95% CI: 0.73-3.02, P=0.28).

CONCLUSION

GDM is a risk marker for NAFLD and represents an opportunity to identify women at risk for NAFLD at a young age and may be mediated by the development of incident DM.

Higher pericardial adiposity is associated with prevalent diabetes: The Coronary Artery Risk Development in Young Adults study

BACKGROUND AND AIMS

Pericardial adipose tissue (PAT) is located on both sides of the pericardium. We tested whether PAT was associated with prevalent diabetes at the year 25 exam of the Coronary Artery Risk Development in Young Adults (CARDIA) study.

METHODS AND RESULTS

The CARDIA Year 25 exam (2010-2011) included complete data for all covariates on 3107 participants. Prevalent diabetes (n = 436) was defined as high fasting (≥126 mg/dl) or 2-h postload glucose (≥200 mg/dl) or HbA1c (≥6.5%) or use of diabetes medications. Volume of PAT was measured from computed tomographic scans. Logistic regression was performed to examine the relationship between quartiles of PAT and diabetes. In regression models adjusted for field center, sex, race, age, systolic blood pressure, total cholesterol, log triglycerides, and treatment with blood pressure and cholesterol lowering medication, PAT volume in the 4th quartile was significantly associated with diabetes status after adjustment for BMI (OR 2.57, 95% CI 1.66, 3.98) or visceral adipose tissue (OR 2.08, 95% CI 1.32, 3.29). PAT volume in the 2nd and 3rd quartiles was not significantly associated with diabetes status relative to the first quartile.

CONCLUSIONS

Metabolically active pericardial adipose tissue is associated with prevalent diabetes only at higher volumes independent of overall obesity.

Association of volumetric bone mineral density with abdominal aortic calcification in African ancestry men

SUMMARY

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors.

INTRODUCTION

The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence.

METHODS

Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia.

RESULTS

Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P < 0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45-0.92).

CONCLUSIONS

Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification.

Longitudinal association between serum urate and subclinical atherosclerosis: the Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

The aim of the present study was to determine whether serum urate (sUA) concentration is positively associated with subclinical atherosclerosis, independent of body mass index (BMI), amongst generally healthy adults.

DESIGN AND SETTING

The CARDIA study followed 5115 Black and White individuals aged 18-30 years in 1985-1986 (year 0). Subclinical atherosclerosis comprised coronary artery calcified plaque (CAC; years 15, 20 and 25), and maximum common carotid intima-media thickness (IMT; year 20). sUA (years 0, 10, 15 and 20) was modelled as gender-specific quartiles that were pooled. Discrete-time hazard regressions and generalized linear regressions were used for analyses.

RESULTS

Mean sUA concentration was lower in women than in men and increased with age. Adjusting for demographic and lifestyle factors, the highest versus lowest quartile of sUA at year 0 was associated with a 44% [95% confidence interval (CI) 20%, 73%] greater risk of CAC progression from years 15 to 25 (Ptrend  < 0.001), which was attenuated by adjustment for BMI at year 0 (Ptrend  = 0.45). A stronger association was found between sUA at year 15 and CAC progression at year 20 or 25 (hazard ratio 2.07, 95% CI 1.66, 2.58 for the highest versus lowest sUA quartile Ptrend  < 0.001), which was attenuated, but remained significant with additional adjustment for BMI at year 15 (Ptrend  = 0.01). A greater increment in sUA concentration from year 0 to year 15, independent of change in BMI, was related to a higher risk of CAC progression (Ptrend  < 0.001). Similar associations were found between sUA and IMT, but only in men.

CONCLUSION

sUA may be an early biomarker for subclinical atherosclerosis in young adults; starting in early middle age, sUA predicts subclinical atherosclerosis independently of BMI.

Insight into the sharing of medical images: physician, other health care providers, and staff experience in a variety of medical settings

BACKGROUND

Scant knowledge exists describing health care providers' and staffs' experiences sharing imaging studies. Additional research is needed to determine the extent to which imaging studies are shared in diverse health care settings, and the extent to which provider or practice characteristics are associated with barriers to viewing external imaging studies on portable media.

OBJECTIVE

This analysis uses qualitative data to 1) examine how providers and their staff accessed outside medical imaging studies, 2) examine whether use or the desire to use imaging studies conducted at outside facilities varied by provider specialty or location (urban, suburban, and small town) and 3) delineate difficulties experienced by providers or staff as they attempted to view and use imaging studies available on portable media.

METHODS

Semi-structured interviews were conducted with 85 health care providers and medical facility staff from urban, suburban, and small town medical practices in North Carolina and Virginia. The interviews were audio recorded, transcribed, then systematically analyzed using ATLAS.ti.

RESULTS

Physicians at family and pediatric medicine practices rely primarily on written reports for medical studies other than X-rays; and thus do not report difficulties accessing outside imaging studies. Subspecialists in urban, suburban, and small towns view imaging studies through internal communication systems, internet portals, or portable media. Many subspecialists and their staff report experiencing difficulty and time delays in accessing and using imaging studies on portable media.

CONCLUSION

Subspecialists have distinct needs for viewing imaging studies that are not shared by typical primary care providers. As development and implementation of technical strategies to share medical records continue, this variation in need and use should be noted. The sharing and viewing of medical imaging studies on portable media is often inefficient and fails to meet the needs of many subspeciality physicians, and can lead to repeated imaging studies.

Subclinical atherosclerosis, airflow obstruction and emphysema: the MESA Lung Study

Airflow obstruction is an independent risk factor for cardiovascular events in the general population. The affected vascular bed and contribution of emphysema to cardiovascular risk are unclear. We examined whether an obstructive pattern of spirometry and quantitatively defined emphysema were associated with subclinical atherosclerosis in the carotid, peripheral and coronary circulations. The Multi-Ethnic Study of Atherosclerosis recruited participants aged 45-84 yrs without clinical cardiovascular disease. Spirometry, carotid intima-media thickness (IMT), ankle-brachial index (ABI) and coronary artery calcium (CAC) were measured using standard protocols. Percentage of emphysema-like lung was measured in the lung windows of cardiac computed tomography scans among 3,642 participants. Multiple linear regression was used to adjust for cardiac risk factors, including C-reactive protein. Decrements in forced expiratory volume in 1 s (FEV(1)) and FEV(1)/forced vital capacity ratio were associated with greater internal carotid IMT, particularly among smokers (p=0.03 and p<0.001, respectively) whereas percentage emphysema was associated with reduced ABI regardless of smoking history (p=0.004). CAC was associated with neither lung function (prevalence ratio for the presence of CAC in severe airflow obstruction 0.99, 95% CI 0.91-1.07) nor percentage emphysema. An obstructive pattern of spirometry and emphysema were associated distinctly and independently with subclinical atherosclerosis in the carotid arteries and peripheral circulation, respectively, and were not independently related to CAC.

Association of PNPLA3 SNP rs738409 with liver density in African Americans with type 2 diabetes mellitus

AIM

Non-alcoholic fatty liver disease (NAFLD) is commonly diagnosed in patients with obesity and type 2 diabetes mellitus (T2DM), and has been associated with the single nucleotide polymorphism (SNP) rs738409 in the PNPLA3 gene. This association remains to be investigated in African Americans with T2DM, a group at lower risk for hepatic steatosis relative to European Americans with T2DM.

METHODS

We examined 422 African Americans with T2DM (40.3% male; age: 56.4±9.6 years; Body Mass Index: 35.2±8.2 kg/m(2)), all with measures of liver density reflecting hepatic fat content on abdominal computed tomography, and blood glucose and lipid profiles. Associations between rs738409 and phenotypes of interest were determined using SOLAR, assuming an additive model of inheritance with covariates age, sex, BMI and use of lipid-lowering medications.

RESULTS

Mean±SD liver density was 55.4±10.2 Hounsfield Units. SNP rs738409 in PNPLA3 was significantly associated with liver density (P=0.0075) and hepatic steatosis (P=0.0350), but not with blood glucose, HbA(1c), total cholesterol, triglycerides, high-density or low-density lipoprotein levels or liver function tests (P=0.15-0.96).

CONCLUSION

These findings provide evidence that the PNPLA3 SNP rs738409 contributes to risk for increased liver fat content in African Americans with T2DM, an effect that appears to be independent from serum lipids. Although African Americans are less susceptible to fatty liver than European Americans, PNPLA3 appears to be a risk locus for hepatic steatosis in diabetic African Americans.

Pericardial fat is associated with carotid stiffness in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Arterial stiffness is a prominent feature of vascular aging and a risk factor for cardiovascular disease (CVD). Fat around the heart and blood vessels (i.e. pericardial fat, Pfat) may contribute to arterial stiffness via a local paracrine effect of adipose tissue on the surrounding vasculature. Thus, we determined the association between Pfat and carotid stiffness in 5770 participants (mean age 62 years, 53% female, 25% African American, 24% Hispanic, and 13% Chinese) from the Multi-Ethnic Study of Atherosclerosis.

METHODS AND RESULTS

Pfat was measured by computed tomography, and ultrasonography of the common carotid artery was used to calculate the distensibility coefficient (DC) and Young's modulus (YM). Lower DC and higher YM values indicate stiffer arteries. Pfat quartile was highly associated with demographic, behavioral, anthropometric, hemodynamic, metabolic, and disease variables in both men and women. After adjusting for height, clinical site, CVD risk factors, and medications, a 1 standard deviation (41.91 cm(3)) increment in Pfat was associated with a 0.00007±0.00002 1/mm Hg lower DC (p=0.0002) in men and a 48.1±15.1 mm Hg/mm higher YM in women (p=0.002). Additional adjustment for C-reactive protein, coronary artery calcification, and carotid intima-media thickness had only modest effects. More importantly, adjusting for body mass index and waist circumference did not significantly change the overall results.

CONCLUSION

Higher Pfat is associated with higher carotid stiffness, independent of traditional CVD risk factors and obesity.

Regional fat changes following weight reduction from laparoscopic Roux-en-Y gastric bypass surgery

Fat accumulation in muscle (intermuscular, IM) and viscera plays a role in obesity comorbidities. This study examined the impact of Roux-en-Y gastric bypass (RYGB) surgery in morbid obesity on changes in regional fat and muscle depots, and these body composition markers were correlated with physical function. Women (n = 18) were assessed prior to (baseline) and 12 months following RYGB for regional body composition and physical function. Weight loss from baseline to 12 months was 33.7 (s.e.m. = 1.7)%; total body fat decreased from 86.8 (s.e.m. = 5.8) to 45.8 (s.e.m. = 3.9) kg during follow-up. Differential changes in regional body fat were apparent with a volume loss of 58.4% in visceral fat, 19.8% in abdomen IM fat and 50.7% in thigh IM fat. At baseline, abdomen IM fat volume was related to physical function. There was less loss of abdomen IM fat volume than other depots following surgery; furthermore its relationship with physical function is a novel finding.

Prospective association of serum androgens and sex hormone-binding globulin with subclinical cardiovascular disease in young adult women: the "Coronary Artery Risk Development in Young Adults" women's study

CONTEXT

The role of endogenous androgens and SHBG in the development of cardiovascular disease in young adult women is unclear.

OBJECTIVE

Our objective was to study the prospective association of serum androgens and SHBG with subclinical coronary and carotid disease among young to middle-aged women.

DESIGN AND SETTING

This was an ancillary study to the Coronary Artery Risk Development in Young Adults (CARDIA) study, a population-based multicenter cohort study with 20 yr of follow-up.

PARTICIPANTS

Participants included 1629 women with measurements of serum testosterone and SHBG from yr 2, 10, or 16 and subclinical disease assessment at yr 20 (ages 37-52 yr).

MAIN OUTCOME MEASURES

Coronary artery calcified plaques (CAC) and carotid artery intima-media thickness (IMT) were assessed at yr 20. The IMT measure incorporated the common carotid arteries, bifurcations, and internal carotid arteries.

RESULTS

SHBG (mean of yr 2, 10, and 16) was inversely associated with the presence of CAC (multivariable adjusted odds ratio for women with SHBG levels above the median = 0.59; 95% confidence interval = 0.40-0.87; P = 0.008). SHBG was also inversely associated with the highest quartile of carotid-IMT (odds ratio for women with SHBG levels in the highest quartile = 0.56; 95% confidence interval = 0.37-0.84; P for linear trend across quartiles = 0.005). No associations were observed for total or free testosterone with either CAC or IMT.

CONCLUSION

SHBG levels were inversely associated with subclinical cardiovascular disease in young to middle-aged women. The extent to which low SHBG is a risk marker or has its own independent effects on atherosclerosis is yet to be determined.

Genetic epidemiology of subclinical cardiovascular disease in the diabetes heart study

A genome-wide linkage scan of 357 European American (EA) and 72 African American (AA) pedigrees multiplex for type 2 diabetes mellitus (T2DM) was performed with multipoint nonparametric QTL linkage analysis. Four subclinical measures of cardiovascular disease (CVD): coronary artery (CCP), carotid artery (CarCP), and abdominal aortic calcified plaque (AACP) and carotid artery intima-media thickness (IMT) were mapped. Analyses were adjusted for age, gender, body mass index, and (if appropriate) ethnicity and diabetes status. Evidence for linkage was observed in EA T2DM subjects to CarCP near 16p13 (LOD=4.39 at 8.4 cM; P = 0.00001). When all EA subjects were included, the LOD score was 2.52, suggesting an amplification of the linkage by diabetes. Linkage analysis of a principal components measure of vascular calcium (LOD = 3.85 at 9.3 cM on 16p in EA T2DM subjects) and bivariate analysis of CarCP X IMT (LOD = 3.77 at 9.3 cM on 16p in EA T2DM subjects) were consistent with this linkage. In addition, evidence for linkage was observed with CCP near D15S1515 (LOD = 2.34) in EAs. Additional loci on chromosomes 1, 2, 7, 10, 13, and 21 had LODs > 2.0. The identification of trait-determining polymorphisms underlying these linkages will help delineate risk factors for CVD in T2DM and the general population.

QTL-specific genotype-by-smoking interaction and burden of calcified coronary atherosclerosis: the NHLBI Family Heart Study

BACKGROUND

Calcified coronary plaque (CCP) is a complex trait influenced by both genes and environment, and plausibly an interaction between the two. Because the familial aggregation of CCP has been demonstrated and smoking is a significant, independent predictor of CCP, we assessed the evidence for genotype-by-smoking interaction and conducted linkage analysis of quantitative Agatston CCP scores in participants of the NHLBI Family Heart Study (FHS).

METHODS

During standardized clinical exams smoking habits were ascertained and CCP was quantified with cardiac computed tomography (CT). Among 4387 relationship pairs from 2128 Caucasian examinees variance component analysis was implemented in SOLAR to examine: (1) additive genotype-by-smoking status interaction using a variance component approach; (2) linkage analysis in the full sample and among smoking subsets defined by individual smoking exposure; (3) QTL-specific genotype-by-smoking interaction in the regions that appeared to differentiate between smoking strata.

RESULTS

The prevalence of CCP (and median Agatston score) was 75% (184.6) in men and 48% (51.0) in women. We detected four genome-wide significant logarithm of odds (LOD) scores in samples stratified by individual smoking exposure: chromosome 4 at 122cM (nearest marker D4S2297; robust adjusted LOD=3.1; q=0.053), chromosome 6 at 99cM (nearest marker D6S1056; robust adjusted LOD=3.3; q=0.053), chromosome 11 at 19cM (nearest marker D11S199; robust adjusted LOD=4.0; q=0.02) and chromosome 13 at 77cM (nearest marker D13S892; robust adjusted LOD=3.1; q=0.053). Additive and QTL-specific genotype-by-smoking interaction was detected on chromosomes 4, 6, 11 and 13; all P<0.05. Three of the four QTLs identified in this report have been previously linked to atherosclerosis and harbor interesting candidate genes.

CONCLUSIONS

These findings demonstrate the importance of considering complex interactions in the search for genes that influence the pathogenesis of CCP.

Type 2 diabetes is not independently associated with spinal trabecular volumetric bone mineral density measured by QCT in the Diabetes Heart Study

The purpose of this study was to investigate the association between type 2 diabetes mellitus (DM2) and trabecular volumetric bone mineral density (vBMD) of the thoracic and lumbar spine measured by quantitative computed tomography (QCT) in 483 female (410 with DM2) and 398 male (365 with DM2) adults (age 36-86 years, BMI 16-58, 88% with DM2) in the Diabetes Heart Study. After accounting for familial correlation using generalized estimating equations (GEE), lumbar spine vBMD was positively associated with BMI (r = 0.24, P < 0.0001) and inversely associated with age (r = -0.51, P < 0.0001). In women, age-adjusted thoracic spinal vBMD (mg/ml, mean +/- SE) was higher in diabetics (147.6 +/- 2.3) compared to unaffected individuals (138.6 +/- 3.4) (P = 0.02), with age-adjusted lumbar spinal vBMD showing a similar but non-significant trend (132.9 +/- 2.1 in diabetics vs. 127.2 +/- 3.6 in unaffected individuals, P = 0.15). In contrast, in men, age-adjusted lumbar and thoracic vBMD were not different between diabetics and unaffected controls (lumbar vBMD = 125.0 +/- 1.8 in diabetics and 125.8 +/- 5.6 in unaffected individuals, P = 0.89; thoracic vBMD = 137.4 +/- 2.1 in diabetics vs. 134.2 +/- 5.5 in controls, P = 0.56). After multivariate analysis adjusting for age, sex, race, BMI, physical activity, dietary intake, smoking, and alcohol use, interaction between diabetes status and trabecular vBMD of the spine was no longer observed. In women only, age-adjusted areal BMD (determined by dual X-ray absorptiometry (DXA)) of the spine and hip were significantly higher in diabetics than non-diabetic (all P < 0.05), although the differences disappeared after additional adjustment for BMI. These data suggest that areal BMD measured by DXA and trabecular volumetric BMD measured by QCT are not associated with type 2 diabetes independently from BMI.

Association of genes of lipid metabolism with measures of subclinical cardiovascular disease in the Diabetes Heart Study

BACKGROUND

Dyslipidaemia is a well known risk factor for cardiovascular disease (CVD). Lipid metabolism is affected by a range of genes and proteins. This study investigated whether some of these genes are associated with measures of subclinical CVD.

METHODS

Polymorphisms of paraoxonase 1 and 2, cholesteryl ester transfer protein, hepatic lipase, and lipoprotein lipase were tested for associations with measures of subclinical CVD including carotid intima-media thickness measured by B-mode ultrasound and carotid and coronary arterial calcification measured by computed tomography. Analysis was performed in 620 European American participants in the Diabetes Heart Study, 83% of whom had type 2 diabetes mellitus. Associations of genotypes with subclinical CVD were tested by computing a series of generalised estimating equations.

RESULTS

The Q192R variant of paraoxonase 1 and rs285 of lipoprotein lipase were associated with carotid artery calcium (p values = 0.002 and 0.005, respectively). Paraoxonase 2 S311C was associated with coronary artery calcium (p value = 0.037).

CONCLUSIONS

There is evidence for modest, but significant, association of multiple single nucleotide polymorphisms in lipid genes with measures of subclinical CVD.

Hormone replacement therapy is associated with increased C-reactive protein in women with Type 2 diabetes in the Diabetes Heart Study

AIMS

Increased levels of inflammatory biomarkers, especially C-reactive protein (CRP), are associated with increased risk for cardiovascular disease (CVD) events, such as myocardial infarction, stroke, peripheral vascular disease, and sudden cardiac death. Medical interventions that increase CRP levels, such as hormone replacement therapy (HRT) in post-menopausal women, are under increasing scrutiny. The effect of HRT on CRP levels in women with Type 2 diabetes (T2DM) is not well documented, and conflicting conclusions have been reported. The aim of this study was to determine the influence of HRT on women with diabetes in a large cross-sectional study.

METHODS

Three hundred and twenty-seven post-menopausal women with T2DM from the Diabetes Heart Study participated. Current use of HRT was determined and serum CRP levels were measured using a high-sensitivity ELISA kit. Generalized estimating equation methods were used to assess the relationship of multiple clinical and lifestyle (e.g. smoking) measures on CRP levels including differences between women taking HRT (HRT+) and not taking HRT (HRT-).

RESULTS

Overall serum CRP levels were strongly associated with body mass index (P < 0.0001) and age (P < 0.0001). Of the women, 243 were not using HRT and 84 were using HRT. HRT+ and HRT- women did not differ significantly in measures of clinical traits, with the exception of higher mean low-density lipoprotein cholesterol in HRT- women (P = 0.004). In all models tested, HRT+ women had significantly higher circulating CRP levels, with P-values ranging from 0.0045 to 0.010.

CONCLUSIONS

In this study of serum CRP concentration as a function of HRT in women with Type 2 diabetes, there was consistent evidence for increased circulating CRP levels in women receiving oestrogen-containing HRT. Whether HRT-induced increases in CRP can account for the adverse cardiovascular effects of HRT remains to be established; however, based on these data, there is little reason to believe that diabetic women would be spared from such an effect.

Association analysis of genes in the renin-angiotensin system with subclinical cardiovascular disease in families with Type 2 diabetes mellitus: the Diabetes Heart Study

AIMS

Cardiovascular disease (CVD) is a major complication of Type 2 diabetes mellitus. The renin-angiotensin system (RAS) and nitric oxide production are both important regulators of vascular function and blood pressure. Genes encoding proteins involved in these pathways are candidates for a contribution to CVD in diabetic patients. We have investigated variants of the angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin type 1 receptor (AT1R) and endothelial nitric oxide synthase (NOS3) genes for association with subclinical measures of CVD in families with Type 2 diabetes mellitus (T2DM).

METHODS

Atherosclerosis was measured by carotid intima-media thickness and calcification of the carotid and coronary arteries in 620 European Americans and 117 African Americans in the Diabetes Heart Study. Because of the role of these systems in blood pressure regulation, blood pressure was also investigated.

RESULTS

Compelling evidence of association was not detected with any of the SNPs with any outcome measures after adjustments for covariates despite sufficient power to detect relatively small differences in traits for specific genotype combinations.

CONCLUSIONS

Genetic variation of the RAS and NOS3 genes do not appear to strongly influence subclinical cardiovascular disease or blood pressure in this diabetic population.

The impact of ethnicity and sex on subclinical cardiovascular disease: the Diabetes Heart Study

AIMS/HYPOTHESIS

African-Americans with type 2 diabetes and access to adequate healthcare are at lower risk of clinical coronary artery disease than are white diabetic patients. We evaluated whether ethnic differences in subclinical cardiovascular disease, coronary and carotid artery calcified plaque and carotid artery intima-medial thickness (IMT) were present in members of The Diabetes Heart Study families.

SUBJECTS AND METHODS

In a bi-racial cohort of 1,180 individuals from families enriched for members with type 2 diabetes, we calculated coronary and carotid artery calcified plaque using fast-gated helical computed tomography, and measured carotid artery IMT and clinical risk factor profiles. Generalised estimating equations were used to test for an association between measures of subclinical cardiovascular disease and ethnicity and sex.

RESULTS

After adjustment for age, ethnicity and kidney function, African-Americans had significantly lower amounts of coronary artery calcified plaque (mean+/-SE) (866+/-158 vs 1,915+/-135, respectively; p=0.0466) and carotid artery calcified plaque (179+/-51 vs 355+/-27, respectively; p=0.0240) relative to whites, despite having increased carotid IMT (0.71+/-0.01 vs 0.67+/-0.004 cm, respectively; p=0.0007), and higher blood pressure, albuminuria and HbA1c. Sex-specific analyses revealed that African-American men had significantly lower coronary and carotid artery calcified atheroma than white men. In women, ethnic differences in calcified carotid artery plaque, but not coronary artery plaque, were observed.

CONCLUSIONS/INTERPRETATION

In families enriched for members with type 2 diabetes, African-American men had markedly lower levels of coronary and carotid artery calcified plaque than white men, despite increased carotid artery IMT and conventional risk factors. These findings suggest that susceptibility to subclinical cardiovascular disease differs markedly according to ethnicity and sex.

Heritability of spinal trabecular volumetric bone mineral density measured by QCT in the Diabetes Heart Study

The heritability of trabecular volumetric bone mineral density (BMD) determined by quantitative computed tomography (QCT) has not yet been reported. The purpose of this study was to investigate the heritability of BMD as determined by QCT and DXA in 124 women and 120 men (age 39-83 years, BMI 17-75, 84% type 2 diabetics) from 101 families (232 sibling pairs) in the Diabetes Heart Study. Volumetric BMD had a heritability (h2) estimate of 0.73 (SE = 0.15, P < 0.0001) at the lumbar spine and 0.71 (SE = 0.15, P < 0.0001) at the thoracic spine. Areal BMD heritability estimates were 0.56 for PA spine, 0.43 for total hip, 0.43 for femoral neck, 0.45 for distal radius, 0.42 for mid-radius, and 0.52 for whole body (all P < 0.01). After accounting for familial correlation using generalized estimating equations, volumetric BMD was inversely associated with age (r = -0.52, P < 0.0001) and duration of diabetes (r = -0.24, P < 0.01) and positively associated with body weight (r = 0.25, P < 0.01). In multivariate analysis, adjustment for age, sex, and race lowered the h2 estimates for volumetric BMD at the lumbar (h2 = 0.41, P < 0.01) and thoracic (h2 = 0.48, P < 0.001) spine, increased the h2 estimate for areal BMD at the mid radius (h2 = 0.58, P < 0.0001), and had little effect on the h2 estimate for areal BMD at other sites (h2 = 0.41-0.55, all P < 0.01). Additional adjustment for BMI, duration of diabetes, and physical activity had little effect on the h2 estimates for volumetric BMD or areal BMD except at the hip where they were lowered (h2 = 0.31-0.33, all P < 0.05). These data suggest that, like areal BMD, volumetric BMD is highly heritable and may be used in designing linkage studies to locate genes governing bone metabolism.

Adiponectin as a novel determinant of bone mineral density and visceral fat

Growing evidence suggests that positive associations between fat mass (FM) and bone mineral density (BMD) are mediated by not only biomechanical but also biochemical factors. Adiponectin is a novel adipocyte-derived hormone that regulates energy homeostasis and has anti-inflammatory and anti-atherogenic effects. Unlike other adipokines such as leptin, adiponectin levels decrease in obesity and type 2 diabetes. The purpose of our study was to investigate associations of serum adiponectin with BMD (DXA and QCT), FM (DXA and QCT), and serum leptin and soluble leptin receptor levels in 38 women and 42 men (age 39-81, BMI 17-55, 86% with type 2 diabetes). After adjusting for age, gender, race, smoking, and diabetes status, serum adiponectin was inversely associated with areal BMD (r = -0.20 to -0.3, all P < 0.01), volumetric BMD (r = -0.35 to -0.44, all P < 0.01), and visceral fat volume (r = -0.30, P < 0.01). These associations remained significant after adjusting for whole body fat mass. The associations of adiponectin with subcutaneous fat volume, whole body FM, and serum leptin level were not significant (all P > 0.1). These data suggest that adiponectin may play a role in the protective effects of visceral fat on BMD.

Coronary artery calcium quantification with retrospectively gated helical CT: protocols and techniques

Current generation Helical Computed Tomography, when coupled with cardiac gating can be used to measure coronary vascular calcium. In this article we review the development of retrospectively gated helical computed tomography on a single slice HCT system and its relation to electron beam CT. The impact of heart rate on selection of helical pitch for the creation of a diastolic image set is detailed, as well as, scanning and post-processing techniques are discussed. The development and initial experience of cardiac gating with multidetector CT systems is presented.

Familial aggregation of coronary artery calcium in families with type 2 diabetes

Type 2 diabetes is widely recognized as a major risk factor for atherosclerotic cardiovascular disease, including subclinical atherosclerosis as measured by noninvasive procedures. However, the role of genetic factors that contribute to various measures of subclinical atherosclerosis is largely unknown. We hypothesize that subclinical atherosclerosis, measured as coronary artery calcification (CAC), will be extensive in individuals with type 2 diabetes and that its presence depends on both genetic and environmental factors. The genetic factors should result in the familial aggregation of CAC. To determine the extent of familial aggregation of CAC in the presence of type 2 diabetes, we studied 122 individuals with type 2 diabetes (mean age 60 years) and 13 individuals without diabetes in 56 families. CAC was measured by fast-gated helical computed tomography. Other measured factors included blood pressure, body size, lipids, HbA1c, and self-reported medical history. To test for an association between CAC and these factors while accounting for the potential familial correlation of CAC, generalized estimating equations were used. CAC was detectable in 80% of individuals with diabetes (median score 84, range 0-5,776). Extent of CAC, adjusted for age, was positively associated with male sex (P = 0.0003), reduced HDL (P = 0.02), albumin-to-creatinine ratio (P = 0.008), and cigarette pack-years (P = 0.03). CAC was also positively associated with a history of angina, myocardial infarction, stroke, and vascular procedures (all P < 0.01). HbA1c and fasting glucose were positively, but nonsignificantly, associated with the extent of CAC (P = 0.14 and 0.08, respectively). CAC, adjusted for age, sex, race, and diabetes status, was heritable (h2 = 0.50; P = 0.009). In multivariate analysis with additional adjustment for HDL, BMI, hypertension, and smoking, h2 = 0.40 (P = 0.038). These results suggest that strong (independent) genetic factors as well as environmental factors contribute to the variance of CAC in individuals with type 2 diabetes. In these data, CAC seems heritable and may serve as an important feature in designing studies to map genes contributing to both atherosclerosis and type 2 diabetes.

Stereotactic localization of breast lesions: how it works and methods to improve accuracy

A computer simulation of stereotactic breast biopsy was developed that paralleled the geometric configuration of a currently available breast biopsy system. This model was developed to define and improve the targeting of breast lesions with stereotactic biopsy techniques. Lesions must be clearly identified and accurately targeted on both views for successful localization. Nonvisualization of a lesion may result from overlying tissue or from the geometric configuration of the imaging system. Familiarity with the geometric configuration of the biopsy unit, especially the location of the reference point and center of rotation, facilitates understanding of apparent changes in lesion position (parallax shift). Inaccuracy in lesion targeting on one or both views will manifest predominantly as an error in the calculated z value (depth). The magnitude and direction of this error are largely determined by the direction of the targeting error. Compensatory strategies include use of a long-throw core biopsy gun or directional vacuum-assisted biopsy device and additional sampling along the z axis and should be accompanied by critical evaluation of both pre- and postfire images. Understanding geometric considerations as well as how targeting accuracy affects accuracy in lesion localization should lead to greater success in sampling even challenging breast lesions at stereotactic biopsy.

Coronary calcium: the case for helical computed tomography

This article provides the rationale for using helical (aka spiral, conventional, and mechanical) computed tomography (CT) systems from measuring coronary calcium. The current state and active research concerning measuring coronary calcium with single- and multi-slice systems is reviewed. The components of image quality, which are important to cardiac imaging with CT, are discussed. Companion articles will review electron beam CT (EBCT) for measuring coronary calcium and perhaps most importantly the scientific data relating coronary calcium to coronary heart disease and atherosclerosis.

The length of time necessary to break even after converting to digital mammography

The cost differences between film-based mammography (FBM) and digital mammography (DM) were estimated after discussions with hospital personnel and industry representatives. Human resource costs were not included. The fixed cost of FBM per machine was estimated to be $50,000 and the variable cost $4.60 per examination. The fixed cost of DM per machine was estimated to be $102,000 and the variable cost $0.10 per examination. The total number of examinations required to break even was therefore 11,556. At a rate of 15 examinations per machine per day and with 251 working days per year, it would take 3.1 years to break even. In the first year after the break-even point had been attained, $16,943 would be saved for every 3765 examinations performed. Extrapolating to the USA as a whole, in which 23 million mammographic examinations are performed each year, suggests that the annual savings from going filmless would be more than $103 million.

Requirements engineering: the key to designing complex medical systems

A variety of business systems, clinical work systems, instrumentation systems, information systems, infrastructure systems, and management systems interact to make the modern healthcare facility work. The key to designing for such a system is systems engineering, a skill often little appreciated among clinical engineers. At the heart of systems engineering is requirements engineering and management (REAM), which is defined as "the process of discovering, documenting and managing systems requirements." The principal activities of REAM include eliciting, understanding, negotiating, describing, validating, and managing system requirements. When REAM is done improperly, the resulting system will be satisfactory only if chance intervenes. Well-done REAM is likely to bring the project in on time, under budget, and at full performance.

Evaluation of subsecond gated helical CT for quantification of coronary artery calcium and comparison with electron beam CT

OBJECTIVE

Since its introduction early in the 1990s, helical CT has become the predominant technology for obtaining CT images for medical applications. Recent improvements in the temporal resolution of helical CT (subsecond) and the addition of retrospective cardiac gating are combined in this report evaluating cardiac-gated helical CT for quantifying coronary artery calcium. We compare total calcium scores determined on subsecond gated helical CT with the current reference for coronary calcium evaluation, electron beam CT.

MATERIALS AND METHODS

We compared total calcium scores obtained using a general purpose, unmodified helical CT scanner with scores obtained using electron beam CT in 36 individuals who were 68+/-11 years old (age range, 41-85 years).

RESULTS

Correlation coefficients ranged from 0.97 to 0.98 (Pearson's product moment) and from 0.95 to 0.96 (Spearman's rank order), depending on the coronary calcium scoring method used. Agreement in the classification of participants as "healthy" or "diseased" at threshold total calcium scores of 10, 100, 160, 200, 400, and 680 was, respectively, 94%, 97%, 89%, 92%, 94%, and 100% using the conventional electron beam CT scoring method and an equivalent method with helical CT.

CONCLUSION

A general purpose, current generation helical CT scanner equipped for retrospective cardiac gating can accurately quantify coronary calcium, and the results are highly correlated to scores obtained with electron beam CT. As an alternative method for measuring coronary calcium, gated subsecond cardiac helical CT offers greater availability and lower cost, thereby making population-based screening for coronary artery calcium more feasible.

Requirements management: keeping your technology acquisition project under control

Whether you are acquiring clinical or business information systems, patient monitoring systems, or therapeutic and diagnostic systems, the odds are good that the project will be delivered late, will cost far more than predicted, and will not provide all the features promised. The principal reason for project failure is improper management of the requirements of the system. Requirements engineering and management is a skill from the systems engineering profession that can be learned by nearly any professional who is managing a technology acquisition project. The author discusses what requirements engineering and management is and how it is done.

Sonohysterography: the next step in the evaluation of the abnormal endometrium

Sonohysterography is a simple ultrasound (US) procedure that may be used to evaluate the endometrium. The technique involves placement of a 5-F catheter into the endometrial canal with subsequent instillation of sterile saline solution under US guidance. Fifty patients successfully underwent sonohysterography because of apparent abnormal endometrial thickening at transvaginal US, a nonspecific finding. Patients tolerated this procedure well, and no complications were encountered. In the 39 patients who proved to have endometrial pathologic conditions, sonohysterography demonstrated focal processes (polyps, carcinoma, hamartoma) in 15, diffuse processes (hyperplasia, secretory endometrium) in 21, and both focal and diffuse pathologic conditions in three. If a focal process can be delineated, a visually directed biopsy may be necessary. However, if the process is diffuse, a blind aspiration biopsy may be performed on an outpatient basis. In the majority of patients, the diffuse or focal nature of the disease could not be predicted on the basis of initial transvaginal US. Because sonohysterography allows distinction between diffuse and focal abnormalities, it provides physicians with a cost-effective way to plan the next step in case management.

Magnetic resonance contrast agents for neuroimaging. Safety issues

As physicians, we have an obligation to ensure the safety of our patients as well as to inform them of any potential risks associated with diagnostic procedures. The overall safety profile of the magnetopharmaceuticals with current FDA approval is good with regard to acute toxicity. For gadopentetate dimeglumine, toxicity. For gadopentetate dimeglumine, the agent with the greatest clinical experience, the overriding majority of adverse events consists of transient and relatively minor symptoms and reactions. Clinical trials of the newer agents reflect a similar experience but on a much smaller scale. Continued post-marketing surveillance programs should provide more information in the near future. Severe adverse reactions do occur after the administration of magnetopharmaceuticals. These often idiosyncratic and anaphylactoid reactions may cause permanent injury or death. In the two reported cases to date, the patients had a history of reactive airway disease. The incidence of severe reactions is estimated at 1 in 350,000 to 450,000 for gadopentetate dimeglumine. The rate is considerably lower than that for iodinated contrast agents, both ionic and nonionic. Magnetopharmaceuticals should be considered safe but not innocuous. The small risk must be weighed against the additional diagnostic information that is obtained with magnetopharmaceuticals. Radiologists should be aware of potential complications and have on site equipment and skilled personnel for management should an adverse event occur. The benefits to the patient of reduced morbidity and mortality from improved diagnosis with magnetopharmaceuticals will ensure continued use of current agents as well as development of additional agents.

Patient screening prior to MR imaging: a practical approach synthesized from protocols at 15 U. S. medical centers

The article by Boutin et al. [1] in this issue of the AJR documents a surprinsingly great variation in the MR screening procedures used at different academic centers throughout the United States. Although considerable literature now exists concerning the MR imaging of patients with ferromagnetic implants, devices, and foreign bodies [2-4], no uniform screening protocol to identify such patients has yet been adopted. The Safety Committee of the Society for Magnetic Resonance Imaging (SMRI) has recommended that "each imaging site should develop a standardized policy for screening patients with suspected metallic foreign bodies" [5]. To date, however, the SMRI has neither proposed nor endorsed a specific screening protocol for general use.