Correlates of coronary artery calcified plaque in blacks and whites with type 2 diabetes

Dual-Energy Computed Tomography-Guided Assessment of Visceral Adiposity and Its Correlation With Lipid Function Test: A Retrospective Study

Introduction Obesity, a prevalent global health concern, is associated with various chronic conditions, including cardiovascular diseases and metabolic syndrome. Visceral adiposity, the accumulation of fat around internal organs, has a more significant impact on metabolic health compared to subcutaneous fat. Accurate assessment of visceral fat is critical for predicting metabolic risks. Dual-Energy Computed Tomography (DECT) is emerging as an effective tool for quantifying visceral adiposity, allowing for enhanced tissue differentiation. This study aims to assess visceral adiposity using DECT and explore its correlation with lipid function tests, including cholesterol and triglyceride levels, in a cohort of patients. Materials and methods This retrospective observational study was conducted in the Department of Radiology at Saveetha Medical College and Hospital, Chennai. Data from 100 patients aged 25 to 75 years with a BMI of 25 kg/m² or higher, were analyzed. DECT scans were performed using a Siemens SOMATOM go.Top 128-slice CT scanner (Siemens, Munich) to quantify visceral fat, particularly mesenteric fat. Lipid function tests were conducted to measure total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. Pearson's correlation coefficient was used to analyze the relationship between visceral fat volume and lipid profile components. Results The study found significant correlations between visceral adiposity and lipid profile components. Total Visceral Fat Area (VFA) volume positively correlated with total cholesterol (r = 0.65, p < 0.01), LDL cholesterol (r = 0.58, p < 0.01), and triglycerides (r = 0.52, p < 0.05). An inverse relationship was observed between VFA volume and HDL cholesterol (r = -0.48, p < 0.05). Regression analysis confirmed that VFA volume is an independent predictor of these lipid levels after adjusting for age, gender, and BMI. The study also reported the prevalence of hepatomegaly in 11 (36.6%) cases and fatty liver in nine (30%) cases in the study population, underscoring the metabolic implications of visceral fat accumulation. Conclusion This study highlights the significant role of visceral adiposity in influencing lipid metabolism and associated cardiovascular risks. DECT proved to be a precise and reliable tool for assessing visceral fat and its metabolic implications. The findings suggest that increased visceral fat is associated with adverse lipid profiles, contributing to a higher risk of metabolic disorders. These results emphasize the need for incorporating advanced imaging techniques like DECT in clinical practice for better risk stratification and personalized treatment strategies in patients with obesity and related metabolic conditions.

Prevalence of coronary artery calcification in a multiethnic population in Angola

This article aims to study the prevalence of coronary artery calcification and associated factors in a multiethnic population in Angola.

METHODS

A descriptive, cross-sectional observational study was carried out in a private clinic in Angola. For this purpose, information was collected from sociodemographic and biological data. The selected variables were; history of arterial hypertension, diabetes mellitus, smoking (current and past), alcohol consumption, family history of coronary disease, and coronary calcium score. Independent Mann-Whitney test, Student's t-test and chi-square test were used as appropriate.

RESULTS

The sample consisted of 211 individuals: 156(73.9%) of black race, 37(17.4%) of mixed race and 18(8.4%) of Caucasian race. 126(59.7%) were male. The average age was 56.7 ± 9.3 years. Of the total sample, 158 (74.9%) had a history of hypertension, 50 (23.7%) of diabetes mellitus, and 138 (65.4%) of dyslipidemia. Of the total number of individuals, 21(10.0%) were smokers and 38(18.0%) were ex-smokers, 137 (64.9%) were social drinkers and 44(20.9%) were obese. A significant association was found between calcification of the coronary arteries and aging (p <.001), Caucasian race (p =.037), and a history of diabetes mellitus, dyslipidemia and smoking (p <.001, p <.001, p =.012, respectively). Black race and female gender are associated with a lower risk of coronary artery calcification (p =.034 and p =.011, respectively).

CONCLUSION

The present results support the notion that there are racial and ethnic differences in the prevalence of coronary calcification.

Race, Interleukin-6, TMPRSS6 Genotype, and Cardiovascular Disease in Patients With Chronic Kidney Disease

Background Differences in death rate and cardiovascular disease (CVD) between Black and White patients with chronic kidney disease is attributed to sociocultural factors, comorbidities, genetics, and inflammation. Methods and Results We examined the interaction of race, plasma IL-6 (interleukin-6), and TMPRSS6 genotype as determinants of CVD and mortality in 3031 Chronic Renal Insufficiency Cohort study participants. The primary outcomes were all-cause mortality and a composite of incident myocardial infarction, peripheral artery disease, stroke, and heart failure. During the median follow-up of 10 years, Black patients with chronic kidney disease experienced a significantly higher mortality (34% versus 26%) and CVD composite (41% versus 28%) compared with White patients. After adjustment, TMPRSS6 genotype did not associate with the outcomes. The adjusted hazard ratio for mortality (4.11 [2.48-6.80], P<0.001) and CVD composite (2.52 [1.96-3.24], P<0.001) were higher for the highest versus lowest IL-6 quintile. The adjusted hazards for death per 1-quintile increase in IL-6 in White and Black individuals were 1.53 (1.42-1.64) versus 1.29 (1.20-1.38) (P<0.001), respectively. For CVD composite they were 1.61 (1.50-1.74) versus 1.30 (1.22-1.39) (P<0.001), respectively. In Cox proportional hazard models that included IL-6, there was no longer a racial disparity for death (1.01 [0.87-1.16], P=0.92), but significant unexplained mediation remained for CVD (1.24 [1.07-1.43]; P=0.004). Path models that included IL-6, diabetes, and urine albumin to creatinine ratio were able to identify variables responsible for racial disparity in mortality and CVD. Conclusions Racial differences in mortality and CVD among patients with chronic kidney disease could be explained by good-fitting path models that include selected mediator variables including diabetes and plasma IL-6.

Racial Disparities in the Cardiac Computed Tomography Assessment of Coronary Artery Disease: Does Gender Matter

Coronary heart disease (CHD) represents a significant healthcare burden in terms of hospital resources, morbidity, and mortality. Primary prevention and early detection of risk factors for the development of CHD are pivotal to successful intervention programs and prognostication. Yet, there remains a paucity of evidence regarding differences in the assessment of these risk factors and the tools of assessment among different ethnicities. We conducted a narrative review to assess the utility of cardiac computed tomography, particularly coronary artery calcification (CAC), in different ethnicities. We also looked to see whether age, sex, comorbidities, and genetic background have peculiar influences on CAC. In this review, we highlight some of the pivotal studies regarding the question of CAC in relation to the development of CHD among different ethnicities. We identify several key trends in the literature showing that although African Americans have high rates of CHD, their risk of CAC may be relatively lower compared with other ethnicities. Similarly, South Asian patients may be at a high risk for adverse cardiac events due to elevated CAC. We also note that several studies are limited by small sample size and were based on 1 large cohort study. Future studies should include a large international prospective cohort to truly evaluate the effects of ethnicity on CAC and CHD risk. To appropriately apply CAC in the clinical practice, the variations in its scoring based on a subject's age, sex, comorbidity, and ethnicity should be addressed and interpreted beforehand.

Diabetes and Subclinical Coronary Atherosclerosis

It is well known that diabetic patients have a high risk of cardiovascular events, and although there has been a tremendous effort to reduce these cardiovascular risks, the incidence of cardiovascular morbidity and mortality in diabetic patients remains high. Therefore, the early detection of coronary artery disease (CAD) is necessary in those diabetic patients who are at risk of cardiovascular events. Significant medical and radiological advancements, including coronary computed tomography angiography (CCTA), mean that it is now possible to investigate the characteristics of plaques, instead of solely evaluating the calcium level of the coronary artery. Recently, several studies reported that the prevalence of subclinical coronary atherosclerosis (SCA) is higher than expected, and this could impact on CAD progression in asymptomatic diabetic patients. In addition, several reports suggest the potential benefit of using CCTA for screening for SCA in asymptomatic diabetic patients, which might dramatically decrease the incidence of cardiovascular events. For these reasons, the medical interest in SCA in diabetic patients is increasing. In this article, we sought to review the results of studies on CAD in asymptomatic diabetic patients and discuss the clinical significance and possibility of using CCTA to screen for SCA.

APOL1 nephropathy risk variants do not associate with subclinical atherosclerosis or left ventricular mass in middle-aged black adults

Prior studies reported associations of APOL1 nephropathy risk variants with subclinical atherosclerosis. However, these findings were limited to older individuals with high comorbidities. To evaluate this in younger individuals, we calculated associations of APOL1 risk variants (high risk [2 risk variants] vs. low risk [0-1 risk variant]) with prevalent, incident, or progressive coronary artery calcification, a carotid intima media thickness over the 90th percentile, and left ventricular hypertrophy in 1315 black participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study. The mean age of this cohort was 44.6 years and their mean estimated glomerular filtration rate was 102.5 ml/min/1.73m2. High-risk participants were found to be younger and have a higher prevalence of albuminuria than low-risk participants. In Poisson regression models adjusted for comorbidities and kidney function, the risk of prevalent coronary artery calcification (relative risk [95% confidence interval] 1.12 [0.72,1.71]), the incident coronary artery calcification (1.50 [0.87,2.59]), and the progression of coronary artery calcification (1.40 [0.88,2.23]) did not significantly differ in high vs. low-risk participants. Furthermore, the risk of carotid intima media thickness over the 90th percentile (1.28 [0.78,2.10]) and left ventricular hypertrophy (1.02[0.73,1.43]) did not significantly differ in high vs. low-risk participants in fully-adjusted models. Thus, APOL1 risk variants did not associate with subclinical markers of atherosclerosis or left ventricular hypertrophy in middle-aged black adults with preserved kidney function.

Genome-wide association study of coronary artery calcified atherosclerotic plaque in African Americans with type 2 diabetes

Background

Coronary artery calcified atherosclerotic plaque (CAC) predicts cardiovascular disease (CVD). Despite exposure to more severe conventional CVD risk factors, African Americans (AAs) are less likely to develop CAC, and when they do, have markedly lower levels than European Americans. Genetic factors likely contribute to the observed ethnic differences. To identify genes associated with CAC in AAs with type 2 diabetes (T2D), a genome-wide association study (GWAS) was performed using the Illumina 5 M chip in 691 African American-Diabetes Heart Study participants (AA-DHS), with replication in 205 Jackson Heart Study (JHS) participants with T2D. Genetic association tests were performed on the genotyped and 1000 Genomes-imputed markers separately for each study, and combined in a meta-analysis.

Results

Single nucleotide polymorphisms (SNPs), rs11353135 (2q22.1), rs16879003 (6p22.3), rs5014012, rs58071836 and rs10244825 (all on chromosome 7), rs10918777 (9q31.2), rs13331874 (16p13.3) and rs4459623 (18q12.1) were associated with presence and/or quantity of CAC in the AA-DHS and JHS, with meta-analysis p-values ≤8.0 × 10⁻⁷. The strongest result in AA-DHS alone was rs6491315 in the 13q32.1 region (parameter estimate (SE) = −1.14 (0.20); p-value = 9.1 × 10⁻⁹). This GWAS peak replicated a previously reported AA-DHS CAC admixture signal (rs7492028, LOD score 2.8).

Conclusions

Genetic association between SNPs on chromosomes 2, 6, 7, 9, 16 and 18 and CAC were detected in AAs with T2D from AA-DHS and replicated in the JHS. These data support a role for genetic variation on these chromosomes as contributors to CAC in AAs with T2D, as well as to variation in CAC between populations of African and European ancestry.

Electronic supplementary material

The online version of this article (10.1186/s12863-017-0572-9) contains supplementary material, which is available to authorized users.

Diabetes and Clinical and Subclinical CVD

Diabetes mellitus is a major cardiovascular risk factor and its prevalence has been increasing globally. This review examines the contributions of the MESA (Multi-Ethnic Study of Atherosclerosis), a diverse American cohort (6,814 adults ages 45 to 84, recruited from 2000 to 2002, 50% female, 62% nonwhite) toward understanding the relationship between diabetes and clinical and subclinical cardiovascular disease. People with diabetes have a high burden of subclinical vascular disease as measured by coronary artery calcification (CAC), carotid artery intima-media thickness, valvular calcification, and alterations in left ventricular structure. CAC substantially improves cardiovascular risk prediction. Among adults with diabetes, 63% had CAC >0; above CAC >400 Agatston units the event rate was 4% annually, whereas an absence of CAC was a marker of a very low cardiovascular disease rate (0.4% to 0.1% annually). These stark differences in rates may have implications for screening and/or targeted prevention efforts based on CAC burden. MESA has also provided insight on diabetes epidemiology.

Vitamin D Associations With Renal, Bone, and Cardiovascular Phenotypes: African American-Diabetes Heart Study

CONTEXT

Vitamin D binding protein (DBP) is an important determinant of bioavailable vitamin D (BAVD) and may provide clues to racial variation in osteoporosis and atherosclerosis.

OBJECTIVE

The objective was to assess relationships between DBP, BAVD, 25-hydroxyvitamin D (25OHD), and 1,25 di-hydroxyvitamin D (1,25OH2D) with kidney, bone, adipose, and atherosclerosis phenotypes in African Americans with type 2 diabetes.

DESIGN

Cross-sectional (N = 545) and longitudinal (N = 288; mean 5.1 ± 0.9-year follow-up) relationships between vitamin D concentrations with renal phenotypes, vertebral bone mineral density, aorto-iliac, coronary artery, and carotid artery calcified plaque (CP), and adipose tissue volumes were studied.

SETTING

African American-Diabetes Heart Study.

PATIENTS

Participants were 56.7% female with mean ± standard deviation (sd) age 55.6 ± 9.6 years, diabetes duration 10.3 ± 8.2 years, and eGFR 90.9 ± 22.1 ml/min/1.73 m(2).

INTERVENTIONS

None.

MAIN OUTCOMES AND MEASURES

Associations tested between vitamin D and the previously mentioned phenotypes adjusting for age, sex, African ancestry proportion, diabetes duration, statins, smoking, changes in estimated glomerular filtration rate, body mass index, hemoglobin A1c, and blood pressure.

RESULTS

1,25OH2D was inversely associated with change in coronary artery CP (parameter estimate [β] -0.005, standard error [SE] 0.002; P = .037), with a trend for change in carotid artery CP (β -0.007, SE 0.004; P = .074). Further adjustment for renin-aldosterone-system blockade revealed inverse association between 1,25OH2D and change in albuminuria (β -0.004, SE 0.002; P = .037). DBP, BAVD, and 25OHD did not associate significantly with changes in albuminuria, CP, or bone mineral density. BAVD was inversely associated with visceral, subcutaneous, intermuscular, and pericardial adipose volumes.

CONCLUSIONS

In contrast to BAVD and 25OHD, only 1,25OH2D levels were significantly and inversely associated with changes in subclinical atherosclerosis and albuminuria in African Americans, suggesting potential beneficial effects.

Relations between subclinical disease markers and type 2 diabetes, metabolic syndrome, and incident cardiovascular disease: the Jackson Heart Study

OBJECTIVE

The presence of subclinical disease measures has been directly associated with the development of cardiovascular disease (CVD) in whites. African Americans (AAs) in the U.S. are at higher risk of CVD compared with non-Hispanic whites; however, data on the prevalence of subclinical disease measures in AAs and their association to CVD remain unclear and may explain the higher CVD risk in this group.

RESEARCH DESIGN AND METHODS

We evaluated 4,416 participants attending the first examination of the Jackson Heart Study (mean age 54 years; 64% women) with available subclinical disease measures.

RESULTS

There were 1,155 participants (26%) with subclinical disease, defined as the presence of one or more of the following: peripheral arterial disease, left ventricular hypertrophy, microalbuminuria, high coronary artery calcium (CAC) score, and low left ventricular ejection fraction. In cross-sectional analyses using multivariable-adjusted logistic regression, participants with metabolic syndrome (MetS) or diabetes (DM) had higher odds of subclinical disease compared with those without MetS and DM (odds ratios 1.55 [95% CI 1.30-1.85] and 2.86 [95% CI 2.32-3.53], respectively). Furthermore, the presence of a high CAC score and left ventricular hypertrophy were directly associated with the incidence of CVD (265 events) in multivariable-adjusted Cox proportional hazards regression models (P < 0.05). In prospective analyses, having MetS or DM significantly increased the hazard of incident CVD, independent of the presence of subclinical disease (P < 0.001).

CONCLUSIONS

In our community-based sample of AAs, we observed a moderately high prevalence of subclinical disease, which in turn translated into a greater risk of CVD, especially in people with MetS and DM.

Population ancestry and genetic risk for diabetes and kidney, cardiovascular, and bone disease: modifiable environmental factors may produce the cures

Variable rates of disease observed between members of different continental population groups may be mediated by inherited factors, environmental exposures, or their combination. This article provides evidence in support of differential allele frequency distributions that underlie the higher rates of nondiabetic kidney disease in the focal segmental glomerulosclerosis spectrum of disease and lower rates of coronary artery calcified atherosclerotic plaque and osteoporosis in populations of African ancestry. With recognition that these and other common complex diseases are affected by biological factors comes the realization that targeted manipulation of environmental exposures and pharmacologic treatments will have different effects based on genotype. The present era of precision medicine will couple one's genetic makeup with specific therapies to reduce rates of disease based on the presence of disease-specific alleles.

The influence of subclinical cardiovascular disease and related risk factors on cognition in type 2 diabetes mellitus: The DHS-Mind study

We hypothesized that measures of coronary artery calcified plaque (CAC) collected at baseline from the Diabetes Heart Study (DHS) would explain associations between cognition and diabetes collected at follow-up approximately 7 years later. The DHS is a sibling study of cardiovascular disease (CVD) in a cohort with a high prevalence of type 2 diabetes (~80%). Associations between baseline CAC and cognitive performance were tested using generalized estimating equations and mixed effects models to adjust for familial relationships. Diabetes status was associated (p<0.05) with poorer performance on tests of verbal memory, processing speed, and semantic fluency adjusting for age, sex, education, and hypertension status. As hypothesized, including CAC in the statistical model attenuated this association. Additionally, CAC and fasting glucose predicted performance in tasks not associated with diabetes status in this study (Stroop Task, Phonemic Fluency). These results confirm work attributing the heterogeneity of cognitive outcomes in type 2 diabetes to subclinical risk factors that combine to affect different aspects of brain function. Importantly, these results imply that risk factor intervention should begin before comorbidities, particularly CVD, become clinically apparent.

Vascular calcification in South African dialysis patients: ethnic variation, prevalence, detection and haemodynamic correlates

AIM

Studies from the US have shown little effect of ethnicity on vascular calcification in dialysis patients. This has not been examined in the multi-ethnic population of South Africa where genetic and environmental differences may exist. We assessed the extent and severity of vascular calcification in South African dialysis patients according to race and known risk factors. We further evaluated the association of abdominal aorta calcification with coronary artery calcification.

METHOD

Seventy-five CKD-5D patients and 20 healthy controls were enrolled consecutively. All subjects underwent chest computed tomography for coronary calcium score and abdominal X-ray for abdominal aorta calcium score. Ambulatory blood pressure monitoring was generated via radial artery applanation tonometry.

RESULTS

Coronary calcification was present in 38.6% of patients and was associated with age and prior cardiovascular disease on multivariate analyses. The median coronary calcium score in black patients was 0 (IQR 0) and 66 in non-Blacks (IQR 383, P < 0.001); controls had a coronary calcium score of 0 (IQR 0). Black race remained a significant negative predictor for coronary calcification after adjustment, prevalence ratio = 0.14 and 95% confidence interval (CI): 0.0-0.53. Vascular calcification was not associated with any ambulatory blood pressure parameter. Using receiver operator characteristic curves, an abdominal aorta calcification score of ≥1 showed an area under the curve of 0.83 to predict a coronary calcium score ≥ 10.

CONCLUSION

Black race appears to protect from vascular calcification in South African CKD-5D patients and this warrants further study regarding the underlying mechanism. The abdominal X-ray is a useful screening tool for coronary calcification.

Admixture mapping of coronary artery calcified plaque in African Americans with type 2 diabetes mellitus

BACKGROUND

The presence and severity of coronary artery calcified plaque (CAC) differs markedly between individuals of African and European descent, suggesting that admixture mapping may be informative for identifying genetic variants associated with subclinical cardiovascular disease.

METHODS AND RESULTS

Admixture mapping of CAC was performed in 1040 unrelated African Americans with type 2 diabetes mellitus from the African American-Diabetes Heart Study, Multi-Ethnic Study of Atherosclerosis and Family Heart Study using the Illumina custom ancestry informative marker panel. All cohorts obtained computed tomography scanning of the coronary arteries using identical protocols. For each ancestry informative marker, the probability of inheriting 0, 1, and 2 copies of a European-derived allele was determined. Linkage analysis was performed by testing for association between each ancestry informative marker using these probabilities and CAC, accounting for global ancestry, age, sex, and study. Markers on 1p32.3 in the GLIS1 gene (rs6663966, logarithm of odds [LOD]=3.7), 1q32.1 near CHIT1 (rs7530895, LOD=3.1), 4q21.2 near PRKG2 (rs1212373, LOD=3.0), and 11q25 in the OPCML gene (rs6590705, LOD=3.4) had statistically significant LOD scores, whereas markers on 8q22.2 (rs6994682, LOD=2.7), 9p21.2 (rs439314, LOD=2.7), and 13p32.1 (rs7492028, LOD=2.8) manifested suggestive evidence of linkage. These regions were uniformly characterized by higher levels of European ancestry associating with higher levels or odds of CAC. Findings were replicated in 1350 African Americans without diabetes mellitus and 2497 diabetic European Americans from Multi-Ethnic Study of Atherosclerosis and the Diabetes Heart Study.

CONCLUSIONS

Fine mapping these regions will likely identify novel genetic variants that contribute to CAC and clarify racial differences in susceptibility to subclinical cardiovascular disease.

Relationships between serum MCP-1 and subclinical kidney disease: African American-Diabetes Heart Study

Background

Monocyte chemoattractant protein-1 (MCP-1) plays important roles in kidney disease susceptibility and atherogenesis in experimental models. Relationships between serum MCP-1 concentration and early nephropathy and subclinical cardiovascular disease (CVD) were assessed in African Americans (AAs) with type 2 diabetes (T2D).

Methods

Serum MCP-1 concentration, urine albumin:creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and atherosclerotic calcified plaque (CP) in the coronary and carotid arteries and infrarenal aorta were measured in 479 unrelated AAs with T2D. Generalized linear models were fitted to test for associations between MCP-1 and urine ACR, eGFR, and CP.

Results

Participants were 57% female, with mean ± SD (median) age 55.6±9.5 (55.0) years, diabetes duration 10.3±8.2 (8.0) years, urine ACR 149.7±566.7 (14.0) mg/g, CKD-EPI eGFR 92.4±23.3 (92.0) ml/min/1.73m², MCP-1 262.9±239.1 (224.4) pg/ml, coronary artery CP 280.1±633.8 (13.5), carotid artery CP 47.1±132.9 (0), and aorta CP 1616.0±2864.0 (319.0). Adjusting for age, sex, smoking, HbA_1c, BMI, and LDL, serum MCP-1 was positively associated with albuminuria (parameter estimate 0.0021, P=0.04) and negatively associated with eGFR (parameter estimate −0.0003, P=0.001). MCP-1 remained associated with eGFR after adjustment for urine ACR. MCP-1 levels did not correlate with the extent of CP in any vascular bed, HbA_1c or diabetes duration, but were positively associated with BMI. No interaction between BMI and MCP-1 was detected on nephropathy outcomes.

Conclusions

Serum MCP-1 levels are associated with eGFR and albuminuria in AAs with T2D. MCP-1 was not associated with subclinical CVD in this population. Inflammation appears to play important roles in development and/or progression of kidney disease in AAs.

Prevalence and progression of peripheral vascular calcification in type 2 diabetes subjects with preserved kidney function

AIMS

To determine predictors of prevalence and progression of peripheral vascular calcification (VC) in type 2 diabetes (DM) subjects with preserved kidney function.

METHODS

Fifty-eight subjects (age 63 ± 11.6 years) with type 2 DM and serum creatinine <125 μmol/l were studied. A CT scan of femoral, posterior tibial and dorsalis pedis arteries was carried out at baseline and at one year. Serum osteoprotegerin (OPG) and RANKL were measured along with routine biochemistry.

RESULTS

Seventy-eight percent of patients had baseline VC, 47% with femoral VC, 49% with VC at two sites - femoral and foot, and 4% foot VC alone. Age, ethnicity, peripheral neuropathy and eGFR were independent predictors of baseline VC. Baseline calcification was the most important predictor of VC progression and was present in all subjects with progression compared to 35% of non-progressors (p < 0.001). Exclusion of demographic factors from models revealed neuropathy and serum OPG levels as independent predictors of both; baseline VC and progression.

CONCLUSIONS

Subjects with type 2 DM and well-preserved renal function had a high prevalence of VC, which was rapidly progressive especially in those with baseline VC. Age, ethnicity, neuropathy, smoking and eGFR were predictors of baseline VC and progression.

Effect of race and genetics on vitamin D metabolism, bone and vascular health

The pathophysiology of chronic kidney disease-mineral and bone disorder accounts for an inverse relationship between bone mineralization and vascular calcification in progressive nephropathy. Inverse associations between bone mineral density (BMD) and calcified atherosclerotic plaque are also observed in individuals of European and African ancestry without nephropathy, suggesting a mechanistic link between these processes that is independent of kidney disease. Despite lower dietary calcium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, African Americans have higher BMD and develop osteoporosis less frequently than do European Americans. Moreover, despite having more risk factors for cardiovascular disease, African Americans have a lower incidence and severity of calcified atherosclerotic plaque formation than do European Americans. Strikingly, evidence is now revealing that serum 25(OH)D and/or 1,25 dihydroxyvitamin D levels associate positively with atherosclerosis but negatively with BMD in African Americans; by contrast, vitamin D levels associate negatively with atherosclerosis and positively with BMD in individuals of European ancestry. Biologic phenomena, therefore, seem to contribute to population-specific differences in vitamin D metabolism, bone and vascular health. Genetic and mechanistic approaches used to explore these differences should further our understanding of bone-blood vessel relationships and explain how African ancestry protects from osteoporosis and calcified atherosclerotic plaque, provided that access of African Americans to health care is equivalent to individuals of European ethnic origin. Ultimately, in our opinion, a new mechanistic understanding of the relationships between bone mineralization and vascular calcification will produce novel approaches for disease prevention in aging populations.

Ethnic differences in the development of albuminuria: the DISTANCE study

OBJECTIVES

To determine whether ethnic differences in the incidence of albuminuria are present in patients with diabetes, and to identify social, behavioral, and provider factors that explain ethnic differences.

STUDY DESIGN

Survey follow-up design with a race-stratified baseline survey (2005-2006) in diabetic patients from a nonprofit, fully integrated healthcare system in Northern California. We followed the 10,596 respondents (30% whites, 20% blacks, 23% Hispanics, 14% Asians, and 13% Filipinos) without evidence of prevalent albuminuria at baseline.

METHODS

Incident albuminuria was defined by positive dipstick urinalysis (>1) or urine albumin to creatinine level (>30 mg/g), and confirmed with repeat testing at least 3 months later.

RESULTS

The 27,292 person-years of observation yielded 981 incident albuminuria events. Agestandardized rates of albuminuria (per 1000 person-years) ranged from 13.6 (95% confidence interval [CI] 10.5-17.0) in whites to 27.8 (CI 18.2- 38.3) in blacks. In fully adjusted Cox models, the hazard ratio for blacks (1.22, 95% CI 1.09-1.38), Asians (1.35, 95% CI 1.13-1.61), and Filipinos (1.93, 95% CI 1.61-2.32), but not Hispanics, was significantly greater than it was for whites. In some cases, point estimates changed markedly from the base model when fully adjusted for potential confounders. Moreover, adjustment for an array of potentially mediating factors explained only a small proportion of the observed ethnic disparities.

CONCLUSIONS

Despite uniform medical care coverage, Filipinos, blacks, and Asians with diabetes developed albuminuria at higher rates than white and Hispanic adults.