Progression of coronary artery calcium in type 1 diabetes mellitus

Epicardial and intra-thoracic adipose tissue and cardiovascular calcifications in type 1 diabetes (T1D) in epidemiology of diabetes Interventions and Complications (EDIC): A pilot study

Objective

Coronary artery, aortic valve, and descending aorta calcification (CAC, AVC, DAC) are manifestations of atherosclerosis, and cardiac epicardial adipose tissue (EAT) indicates heart adiposity. This study explored the association between cardiac adipose tissue and cardiovascular calcification in participants with long-standing T1D.

Methods

EAT and intra-thoracic adipose tissue (IAT) were measured in 100 T1D subjects with cardiac computed tomography (CT) scans in the EDIC study. Volume analysis software was used to measure fat volumes. Spearman correlations were calculated between CAC, AVC, DAC with EAT, and IAT. Associations were evaluated using multiple linear and logistic regression models.

Results

Participants ranged in age from 32 to 57. Mean EAT, and IAT were 38.5 and 50.8 mm3, respectively, and the prevalence of CAC, AVC, and DAC was 43.6 %, 4.7 %, and 26.8 %, respectively. CAC was positively correlated with age (p-value = 0.0001) and EAT (p-value = 0.0149) but not with AVC and DAC; IAT was not associated with calcified lesions. In models adjusted for age and sex, higher levels of EAT and IAT were associated with higher CAC (p-value < 0.0001 for both) and higher AVC (p-values of 0.0111 and 0.0053, respectively), but not with DAC. The associations with CAC remained significant (p-value < 0.0001) after further adjustment for smoking, systolic blood pressure, BMI, and LDL, while the associations with AVC did not remain significant.

Conclusion

In participants with T1D, higher EAT and IAT levels are correlated with higher CAC scores. EAT and IAT were not independently correlated with DAC or AVC.

Screening for Subclinical Atherosclerosis and the Prediction of Cardiovascular Events in People with Type 1 Diabetes

People with type 1 diabetes (T1D) have a high cardiovascular disease (CVD) risk, which remains the leading cause of death in this population. Despite the improved control of several classic risk factors, particularly better glycaemic control, cardiovascular morbidity and mortality continue to be significantly higher than in the general population. In routine clinical practice, estimating cardiovascular risk (CVR) in people with T1D using scales or equations is often imprecise because much of the evidence comes from pooled samples of people with type 2 diabetes (T2D) and T1D or from extrapolations of studies performed on people with T2D. Given that T1D onsets at a young age, prolonged exposure to the disease and its consequences (e.g., hyperglycaemia, changes in lipid metabolism or inflammation) have a detrimental impact on cardiovascular health. Therefore, it is critical to have tools that allow for the early identification of those individuals with a higher CVR and thus be able to make the most appropriate management decisions in each case. In this sense, atherosclerosis is the prelude to most cardiovascular events. People with diabetes present pathophysiological alterations that facilitate atherosclerosis development and that may imply a greater vulnerability of atheromatous plaques. Screening for subclinical atherosclerosis using various techniques, mainly imaging, has proven valuable in predicting cardiovascular events. Its use enables the reclassification of CVR and, therefore, an individualised adjustment of therapeutic management. However, the available evidence in people with T1D is scarce. This narrative review provides and updated overview of the main non-invasive tests for detecting atherosclerosis plaques and their association with CVD in people with T1D.

Autoimmune diseases and their prevalence in Saudi Arabian patients with type 1 diabetes mellitus

OBJECTIVES

To evaluate the prevalence of autoimmune disorders among young and adult populations diagnosed with type 1 diabetes mellitus (T1DM) in Al-Madinah Al-Munawarah, Saudi Arabia, and assess the potential impact of these conditions on other comorbidities.

METHODS

A retrospective, descriptive study examined autoimmune disorders in T1DM youth and adults. A total of 2258 verified T1DMs were tested. Analyzed hospital and laboratory data. Autoimmune T1DM was investigated clinically and laboratory.

RESULTS

A total of 2258 T1DM adults, adolescents, and children were investigated; 500 (22.2%) were under 12, 540 (23.9%) were 13-17, and 1218 (53.9%) were 18 plus. Autoimmune with T1DM was 67.4%. Gender and age affect prevalence. 25.7% of adult females had autoimmune thyroiditis. Children and adolescents have greater rates of celiac disease than adults of both genders. Adrenal insufficiency was more frequent in adults. Adult males had 28.5% polyglandular autoimmune diseases, and women had 19.7%. Type 1 DM and other autoimmune illnesses increase the risk of nephropathy, CVD, and hypoglycemia. Bloodstream biomarkers linked to these disorders corroborate this.

CONCLUSION

Autoimmune diseases in Saudi patients with T1DM exhibited specificity with respect to gender and age. Al-Madinah Al-Munawwarah have a heightened prevalence of autoimmune diseases among young individuals diagnosed with T1DM, such as celiac disease and autoimmune thyroiditis. Conversely, older individuals in the region have been observed to exhibit a greater incidence of adrenal failure and polyglandular autoimmune disorders. Autoimmune diseases that result in nephropathy, CVD, and hypoglycemia are highly prevalent based on biomarker levels.

Hemoglobin A1c Variability Metrics Predict Coronary Artery Calcium and Cardiovascular Events in Type 1 Diabetes: The CACTI Study

CONTEXT

Interventions that decrease mean glucose have reduced rates of micro- and macrovascular complications in type 1 diabetes (T1D). However, the difference in cardiovascular risk between people with T1D and the general population endures, suggesting that factors beyond hemoglobin A1C (HbA1c) normalization drive cardiovascular outcomes.

OBJECTIVE

To determine whether various HbA1c metrics predict anatomic cardiovascular disease (CVD) risk factors and/or CVD events in people with T1D.

METHODS

We used linear regression to analyze the relationship of several HbA1c metrics to anatomic CVD risk factors and then used Cox regression to model their relationship to incident CVD events in the CACTI Study (ClinicalTrials.gov Identifier: NCT00005754).

RESULTS

In linear regression models adjusted for age, sex, and T1D duration, baseline Hba1c (b = 0.3998, P = 0.0236), mean HbA1c (b = 0.5385, P = 0.0109), and HbA1c SD (b = 1.1521, P = 0.0068) were each positively associated with square root transformed coronary artery calcium volume. Conversely, only mean HbA1c (b = 1.659, P = 0.0048) positively associated with pericardial adipose tissue volume. In survival models adjusted for age, sex, and T1D duration, baseline HbA1c [hazard ratio (HR): 1.471, 95% CI: 1.257-1.721], mean HbA1c (HR: 1.850, 95% CI: 1.511-2.264), time-varying HbA1c (HR: 1.500, 95% CI: 1.236-1.821), and HbA1c SD (HR: 1.665, 95% CI: 1.022-2.711) each independently predicted CVD events over 14.3 ± 5.2 person-years of follow-up.

CONCLUSIONS/INTERPRETATION

We found that various HbA1c metrics positively correlated with CAC volume and independently predicted incident CVD events in the CACTI T1D cohort. These associations with CVD events persisted for baseline HbA1c, mean HbA1c, and time-varying HbA1c even after adjustment for numerous CVD risk factors.

Type 1 Diabetes and Associated Cardiovascular Damage: Contribution of Extracellular Vesicles in Tissue Crosstalk

Significance: Type 1 diabetes (T1D) is characterized by the autoimmune destruction of the insulin secreting β-cells, with consequent aberrant blood glucose levels. Hyperglycemia is the common denominator for most of the chronic diabetic vascular complications, which represent the main cause of life reduction in T1D patients. For this disease, three interlaced medical needs remain: understanding the underlying mechanisms involved in pancreatic β-cell loss; identifying biomarkers able to predict T1D progression and its related complications; recognizing novel therapeutic targets. Recent Advances: Extracellular vesicles (EVs), released by most cell types, were discovered to contain a plethora of different molecules (including microRNAs) with regulatory properties, which are emerging as mediators of cell-to-cell communication at the paracrine and endocrine level. Recent knowledge suggests that EVs may act as pathogenic factors, and be developed into disease biomarkers and therapeutic targets in the context of several human diseases. Critical Issues: EVs have been recently shown to sustain a dysregulated cellular crosstalk able to exacerbate the autoimmune response in the pancreatic islets of T1D; moreover, EVs were shown to be able to monitor and/or predict the progression of T1D and the insurgence of vasculopathies. Future Directions: More mechanistic studies are needed to investigate whether the dysregulation of EVs in T1D patients is solely reflecting the progression of diabetes and related complications, or EVs also directly participate in the disease process, thus pointing to a potential use of EVs as therapeutic targets/tools in T1D. Antioxid. Redox Signal. 36, 631-651.

Early Markers of Cardiovascular Disease Associated with Clinical Data and Autosomal Ancestry in Patients with Type 1 Diabetes: A Cross-Sectional Study in an Admixed Brazilian Population

Patients with type 1 diabetes (T1D) have a higher risk of developing cardiovascular disease (CVD), which is a major cause of death in this population. This study investigates early markers of CVD associated with clinical data and autosomal ancestry in T1D patients from an admixed Brazilian population. A cross-sectional study was conducted with 99 T1D patients. The mean age of the study sample was 27.6 years and the mean duration of T1D was 14.4 years. The frequencies of abnormalities of the early markers of CVD were 19.6% in the ankle-brachial index (ABI), 4.1% in the coronary artery calcium score (CACS), and 5% in the carotid Doppler. A significant percentage of agreement was observed for the comparison of the frequency of abnormalities between CACS and carotid Doppler (92.2%, p = 0.041). There was no significant association between the level of autosomal ancestry proportions and early markers of CVD. The ABI was useful in the early identification of CVD in asymptomatic young patients with T1D and with a short duration of disease. Although CACS and carotid Doppler are non-invasive tests, carotid Doppler is more cost-effective, and both have limitations in screening for CVD in young patients with a short duration of T1D. We did not find a statistically significant relationship between autosomal ancestry proportions and early CVD markers in an admixed Brazilian population.

Diabetes Mellitus and Heart Failure

Diabetes mellitus (DM) is a major risk factor for new-onset heart failure (HF) and vice versa. The pathogenesis of new-onset HF in DM is complex and has been largely attributed to the toxic cardiovascular effects of hyperglycemia and relevant metabolic abnormalities (diabetic cardiomyopathy) as well as the frequently coexisting morbidities such as hypertension (HTN), coronary artery disease (CAD), and diabetic nephropathy. In patients with type 1 DM (T1DM), HF develops in the setting of a dysregulated immune response, whereas in most patients with type 2 DM (T2DM), against a background of overweight/obesity. HF prevention in DM is feasible with rigorous treatment of cardiovascular risk factors and selective antidiabetic agents. Conversely, development of new-onset T2DM in HF (cardiogenic DM) is common and has been attributed to an increase in the resistance to insulin, especially in the skeletal muscle, liver, and adipose tissue as well as in diminished insulin secretory response to hyperglycemia by pancreatic β-cells. Cardiogenic DM further deteriorates cardiac dysfunction and adversely affects outcome in HF. Novel lifesaving medications employed in HF management such as sacubitril/valsartan and sodium glucose cotransporter 2 inhibitors (SGLT-2i) have a favorable metabolic profile and lower the incidence of cardiogenic diabetes. Whether mitigation of cardiogenic DM should be a treatment target in HF deserves further investigation.

Cardiovascular Magnetic Resonance as Pathophysiologic Tool in Diabetes Mellitus

Diabetes mellitus can independently contribute to cardiovascular disease and represents a severe risk factor for premature development of cardiovascular disease. A three-fold higher mortality than the general population has been observed in type 1 diabetes mellitus whereas a two- to four-fold increased probability to develop cardiovascular disease has been observed in type 2 diabetes mellitus. Cardiovascular magnetic resonance, a non-radiative modality, is superior to all other modalities in detecting myocardial infarction. The main cardiovascular magnetic resonance sequences used include a) balanced steady-state free precession (bSSFP) for function evaluation; b) T2-W for oedema detection; c) T1 W for ischemia detection during adenosine stress; and d) late gadolinium enhanced T1-W images (LGE), evaluated 15 min after injection of paramagnetic contrast agent gadolinium, which permit the diagnosis of replacement fibrosis, which appears white in the middle of suppressed, nulled myocardium. Although LGE is the technique of choice for diagnosis of replacement fibrosis, it cannot assess diffuse myocardial fibrosis. The application of T1 mapping (native or pre contrast and post contrast) allows identification of diffuse myocardial fibrosis, which is not detectable my other means. Native T1 and Contrast-enhanced T1 mapping are involved in the extracellular volume fraction (ECV) calculation. Recently, 1H-cardiovascular magnetic resonance spectroscopy has been applied to calculate the amount of myocardial triglycerides, but at the moment it is not part of the routine assessment of diabetes mellitus. The multifaceted nature of cardiovascular magnetic resonance has the great potential of concurrent evaluation of function and myocardial ischemia/fibrosis in the same examination and represents an indispensable tool for accurate diagnosis of cardiovascular disease in diabetes mellitus.

Muscle insulin resistance in type 1 diabetes with coronary artery disease

AIMS/HYPOTHESIS

The risk for coronary artery disease (CAD) is substantially increased in type 1 diabetes and it has been postulated that insulin resistance may contribute to this risk. The current study measured insulin resistance in type 1 diabetes with vs without CAD and with a focus upon skeletal muscle, to test the hypothesis that insulin resistance is more severe in participants who have type 1 diabetes and CAD. Additionally, in type 1 diabetes, we examined the hypothesis that insulin resistance is more severe in soleus (an oxidative type muscle) vs tibialis anterior (a more glycolytic type of muscle).

METHODS

Insulin resistance was measured in participants with type 1 diabetes with (n = 9, CAD+) and without CAD (n = 10, CAD-) using euglycaemic insulin infusions combined with positron emission tomography (PET) imaging of [¹⁸F]fluorodeoxyglucose (FDG) uptake into soleus and tibialis anterior skeletal muscles. Coronary artery calcium (CAC) score was quantified by electron beam tomography.

RESULTS

CAD+ participants with type 1 diabetes had a >100-fold higher CAC score than did CAD- participants with type 1 diabetes but groups did not differ in HbA_1c or insulin dose. During clamp studies, CAD+ and CAD- groups had similar glucose disposal but were insulin resistant compared with historical non-diabetic participants (n = 13). FDG uptake by soleus muscle was similarly reduced, overall, in individuals with type 1 diabetes with or without CAD compared with non-diabetic individuals. However, FDG uptake by tibialis anterior muscle was not reduced in CAD- participants with type 1 diabetes while in CAD+ participants with type 1 diabetes it was 75% greater (p < 0.01). Across all participants with type 1 diabetes, FDG uptake by tibialis anterior muscle correlated positively with CAC severity.

CONCLUSIONS/INTERPRETATION

Our study confirms that systemic and skeletal muscle-specific insulin resistance is seen in type 1 diabetes but found that it does not appear to be more severe in the presence of CAD. There were, however, sharp differences between soleus and tibialis anterior muscles in type 1 diabetes: while insulin resistance was clearly manifest in soleus muscle, and was of equal severity in CAD+ and CAD- participants, tibialis anterior did not suggest insulin resistance in participants with type 1 diabetes, as FDG uptake by tibialis anterior correlated positively with CAC severity and was significantly increased in participants with type 1 diabetes and clinical CAD. Graphical abstract.

Cardiovascular Risk in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is associated with premature cardiovascular disease (CVD), but the underlying mechanisms remain poorly understood. The American Diabetes Association and the European Association for the Study of Diabetes recently updated their position statement on the management of type 2 diabetes mellitus (T2DM) to include additional focus on cardiovascular risk; improved management of risk factors in T1DM is also needed. There are important differences in the pathophysiology of CVD in T1DM and T2DM. Hyperglycaemia appears to have a more profound effect on cardiovascular risk in T1DM than T2DM, and other risk factors appear to cause a synergistic rather than additive effect, so achievement of treatment targets for all recognized risk factors is crucial to reducing cardiovascular risk. Here we discuss the evidence for addressing established cardiovascular risk factors, candidate biomarkers and surrogate measurements, and possible interventions.

Ultrasound Tissue Characterization of Carotid Plaques Differs Between Patients with Type 1 Diabetes and Subjects without Diabetes

The aim of the study was to investigate ultrasound tissue characterization of carotid plaques in subjects with and without diabetes type 1 (T1D). B-mode carotid ultrasound was performed to assess the presence and type of plaque in a group of 340 subjects with and 304 without T1D, all of them without cardiovascular disease. One hundred and seven patients with T1D (49.5% women; age 54 ± 9.8 years) and 67 control subjects without diabetes who had at least one carotid plaque were included in the study. The proportion of subjects who had only echolucent plaques was reduced in the group of patients with T1D (48.6% vs. 73.1%). In contrast, the proportion with only echogenic (25.2% vs. 7.5%) and calcified plaques (9.4% vs. 1.5%) was increased compared with subjects without diabetes. Moreover, having at least one echogenic plaque was more frequent in T1D patients compared with subjects without diabetes (49.5% vs. 26.9% p = 0.005). In addition to diabetes (OR 2.28; p = 0.026), age (OR 1.06, p = 0.002) was the other variable associated with echogenic plaque existence in multiple regression analysis. Patients with T1D exhibit a differential pattern of carotid plaque type compared with subjects without diabetes, with an increased frequency of echogenic and extensively calcified plaques.

The role of coronary artery calcification testing in incident coronary artery disease risk prediction in type 1 diabetes

AIMS/HYPOTHESIS

We sought to assess the role of coronary artery calcification (CAC) and its progression in predicting incident coronary artery disease (CAD) in individuals with type 1 diabetes using data from the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study.

METHODS

The present study examined 292 participants who had at least one CAC measure and were free from CAD at baseline; 181 (62%) had repeat CAC assessments 4-8 years later and did not develop CAD between the two CAC measures. The HRs of incident CAD events were estimated using Cox models in categorised or in appropriately transformed CAC scores. C statistics and net reclassification improvement (NRI) were used to assess the added predictive value of CAC for incident CAD.

RESULTS

At baseline, the mean age of participants was 39.4 years and the mean diabetes duration was 29.5 years. There were 76 participants who experienced a first incident CAD event over an average follow-up of 10.7 years. At baseline, compared with those without CAC (Agatston score = 0), the adjusted HR (95% CI) in groups of 1-99, 100-399 and ≥400 was 3.1 (1.6, 6.1), 4.4 (2.0, 9.5) and 4.8 (1.9, 12.0), respectively. CAC density was inversely associated with incident CAD in those with CAC volume ≥100 (HR 0.3 [95% CI 0.1, 0.9]) after adjusting for volume score. Among participants with repeated CAC measures, annual CAC progression was positively associated with incident CAD after controlling for baseline CAC. The HR (95% CI) for above vs below the median annual CAC volume progression was 3.2 (1.2, 8.5). When compared with a model that only included established risk factors, the addition of CAC improved the predictive ability for incident CAD events in the whole group.

CONCLUSIONS/INTERPRETATION

CAC is strongly associated with incident CAD events in individuals with type 1 diabetes; its inclusion in CAD risk models may lead to improvement in prediction over established risk factors.

Possible early detection of coronary artery calcium progression in type 1 diabetes: A case-control study of normoalbuminuric type 1 diabetes patients and matched controls

AIMS

Coronary artery calcium (CAC) is associated with cardiovascular (CV) disease and progression of CAC is an independent predictor of mortality. Type 1 diabetes is associated with increased CV risk, especially in persons with cardiovascular autonomic neuropathy (CAN). This study aimed to examine whether short-term progression of CAC is increased in persons with type 1 diabetes compared to matched controls and if CAN increases risk of CAC progression.

METHODS

Fifty-three normoalbuminuric persons with long-term type 1 diabetes (20 with CAN) were matched in a 1:2 ratio with 106 controls without diabetes according to age, sex and baseline CAC. All were examined twice with cardiac computed tomography scans. Progression of CAC was defined as a value ≥2.5 between the square root-transformed values of follow-up and baseline CAC volume scores.

RESULTS

The participants were examined median (interquartile range) of 25 (23-27) months (type 1 diabetes) and 29 (25-33) months (controls) apart. In multivariable logistic regression, participants with type 1 diabetes had an odds ratio of 3.3 (95% CI 1.3-8.2, p = 0.01) for CAC progression. CAN did not increase progression of CAC (p = 0.64).

CONCLUSIONS

Progression of CAC was increased in well-treated, normoalbuminuric persons with type 1 diabetes compared to matched controls without diabetes, suggesting that type 1 diabetes is a risk factor for short-term progression. This finding could explain some of the increased morbidity and mortality observed in persons with type 1 diabetes, but it does not specifically explain the increased CV risk in persons with CAN.

Coronary artery calcium may stabilize following islet cell transplantation in patients with type 1 diabetes

Islet cell transplantation can functionally cure type 1 diabetes and also improve carotid intima-media thickness. This study provides a preliminary description of changes in coronary artery calcium following islet transplantation, and associated factors. Coronary artery calcium was measured in 14 patients with type 1 diabetes (11 had measures both pre- and post-transplant [mean 2.3 years]) in the University of Illinois at Chicago's clinical trial. Multivariable mixed-effects linear regression of repeated measures was used to quantify calcium change and determine if this change was longitudinally associated with risk/protective factors. Thirteen of the patients were female, with mean baseline age, diabetes duration, and BMI of 47.6 and 28.7 years, and 23.1, respectively. Over half (57%) had detectable coronary artery calcium pre-transplant. Minimal change (0.39 mm³ /y, P = .02) occurred in coronary artery calcium levels pre- to post-transplant. No patient met criteria for calcium progression. Coronary artery calcium was positively associated with total and small VLDL particles (P ≤ .02), statin dose (P = .02), and urine albumin-to-creatinine ratio (P = .04) and negatively associated with free fatty acids (P = .03), total HDL (P = .03), large HDL particles (P = .005), and tacrolimus dose (P = .02). Islet transplant may stabilize coronary artery calcium, with optimal management of lipids and kidney function remaining key therapeutic targets. [NCT00679041].

Relation of Risk Factors and Abdominal Aortic Calcium to Progression of Coronary Artery Calcium (from the Framingham Heart Study)

Coronary artery calcium (CAC) and abdominal aortic calcium (AAC) on multidetector computed tomography (MDCT) permit assessment of the presence and burden of coronary and systemic atherosclerosis. Risk factors for progression of CAC and AAC and the association of AAC with CAC progression have not been well characterized in a community-dwelling cohort. We studied 1,959 asymptomatic participants from the Framingham Heart Study who underwent serial MDCT scans with a median interval of 6.1 years. Primary outcomes were (a) the incidence of CAC and AAC (CAC >0 and AAC >0 with baseline CAC = 0 and AAC = 0) and (b) absolute progression of CAC (CAC > baseline CAC and AAC > baseline AAC). Covariates were collected at adjacent cycle examinations and included age, gender, use of antihypertensive therapy, use of lipid-lowering therapy, cigarette smoking, and total and high-density lipoprotein cholesterol. Predictors for CAC and AAC progression included baseline CAC, baseline AAC, lipid-lowering therapy, diabetes, high-density lipoprotein cholesterol, BMI, and serum creatinine. Multivariable stepwise logistic and linear regression models were used to test the association of these risk factors with CAC and AAC. Those who developed incident CAC on follow-up scanning comprised 18.8% of 1,124 participants, and 84.9% of 780 participants, with detectable baseline CAC, had further progression. Baseline AAC was a predictor of both CAC incidence and progression, independent of other risk factors. In stepwise models, addition of baseline AAC slightly improved the area under the curve from 0.72 (0.68 to 0.76) to 0.74 (0.70 to 0.78). In conclusion, standard cardiovascular disease risk factors are associated with incidence and progression of CAC and AAC, and AAC augments CAC incidence and progression above cardiovascular disease risk factors.

Lipoprotein composition in patients with type 1 diabetes mellitus: Impact of lipases and adipokines

OBJECTIVE

High cardiovascular mortality in patients with type 1 diabetes (T1DM) is widely recognized. Paradoxically, these patients have been shown to have elevated HDL-C and reduced apoB-containing lipoproteins. The purpose of this investigation was to further characterize the lipoprotein composition in T1DM and to assess the role that lipases and adipokines may play in these differences.

METHODS

T1DM patients (89) attending the Diabetes Clinic at the University of Miami and 42 healthy controls were recruited. Clinical characteristics, lipoprotein composition (by ultracentrifugation and HPLC), leptin, and adiponectin were measured in the full cohort, while a subgroup had LPL and hepatic lipase measured.

RESULTS

Subjects were predominately Caucasian and Hispanic. HgbA1c's were above goal while their mean duration of diabetes was >20 years. LPL was 2-fold elevated in diabetic women versus controls (+107%{p=0.001}) with no difference in men. Hepatic lipase was reduced 50% {p<0.001} in women but increased 50% {p=0.079} in men. Leptin was similar to controls in women but reduced in men (-60%{p<0.001}). Adiponectin was elevated in both genders (men: +55%{p=0.018}; women: +46%{p=0.007}). LDL-C was reduced in both diabetic men (-33%{p<0.001}) and women (-24%{p<0.001}) while HDL-C trended higher only in men (+13%{p=0.064}). Both total apoB (men: -31%{p<0.001}; women: -17%{p=0.016}) and triglycerides (men: -49%{p<0.001}; women: -31%{p=0.011}) were reduced in both genders while total apoA-I was increased in both (men: +31%{p<0.001}; women: +19%{p=0.008}). Both men and women had increases in LpA-I (+66%{p<0.001}; +40%{p=0.001}) which accounted for essentially the entire increase in HDL mass. VLDL lipids (men: -53→70%; women: -31→57%) were lower as was apoB (particle number) in men (-51{p<0.001}) with a similar trend in women (-35%{p=0.066}). Cholesterol esters in the particle core were depleted in both genders relative to both apoB (men: -41%; women: -37%) and triglycerides (men: -38%; women: -34%) (all{p<0.009}). There were similar differences in IDL. HDL-L lipids (except triglycerides) (men: +45→74%; women: +49→77%{p<0.006}), apoA-1 (men: +162%; women: +117%{p<0.001}), and apoA-II (men: +64%{p=0.008}; women: +55%{p=0.014}) were higher in T1DM patients. These differences produced dramatic increases in LpA-I (men: +221%; women +139%{p<0.001}) and total HDL-L mass (men: +85%; women: +78%{p<0.001}). ApoM (men: +190%; women: +149%{p<0.001}) was also dramatically increased. Conversely, HDL-D lipids were lower in both genders (-20%→50%) while apoA-I was not different in either. ApoA-II was lower only in the diabetic women (-25%{p=0.015}). LPL activity correlated primarily with IDL(-), LDL(-), HDL-L(+), and HDL-D(-) only in the women. HL correlated weakly with VLDL(+), LDL(+), HDL-L(-), and HDL-D(+) in women but had much stronger correlations with VLDL(-), IDL(-), and HDL-L(+). Adiponectin correlated with VLDL(-), IDL(-), LDL(-), HDL-L(+), and HDL-D(-) in women but only HDL-L(+) and HDL-D(-) in men. Leptin correlated with very few parameters in women but did correlate weakly with several HDL-L(-) and HDL-M(-) parameters.

CONCLUSION

Lipoprotein composition and adipokine concentrations in both genders as well as lipase activities in the women would be expected to reduce the atherosclerotic risk in these patients with T1DM. These data suggest that there are functional lipoprotein abnormalities responsible for their CV risk that are not reflected in their plasma concentrations.

MENSTRUAL AND REPRODUCTIVE FUNCTION IN WOMEN WITH TYPE 1 DIABETES

OBJECTIVE

Menstrual irregularities, reproductive abnormalities, and androgen excess are reported to be more prevalent in women with type 1 diabetes (T1D). The objective of this study was to investigate the prevalence of menstrual irregularities, reproductive abnormalities, and androgen excess among women with T1D and their age-matched controls.

METHODS

A survey requesting information regarding menstrual and reproductive histories was administered to all participants. Results were stratified according to age (18 to 40, 40 to 50, and >50 years).

RESULTS

There were no significant differences between women with and without diabetes in age at menarche, cycle length, or androgen excess in any group. Women who self-reported difficulty with glycemic control were more likely to report irregular menses than controls (P = .04). Among women who reported ever being pregnant, there were fewer pregnancies (P = .02) and live births (P = .002) in women with T1D. Women with T1D reported a lower frequency of oral contraceptive use (P = .003), despite being less likely to smoke (P = .016).

CONCLUSION

Menstrual and reproductive abnormalities were not observed more frequently in women with T1D in this study. Subtle but measurable differences in menstrual and reproductive function were confined to the subgroup of women who perceived poor control of their diabetes. Additional prospective studies of T1D and menstrual and reproductive function would be useful.

Below-knee arterial calcification in type 2 diabetes: association with receptor activator of nuclear factor κB ligand, osteoprotegerin, and neuropathy

CONTEXT

Calcification of the arterial wall in diabetes contributes to the arterial occlusive process occurring below the knee. The osteoprotegerin (OPG)/receptor activator of nuclear factor κB ligand (RANKL) system is suspected to be involved in the calcification process.

OBJECTIVE

The aim of the study was to investigate whether there is a link between arterial calcification in type 2 diabetes and 1) conventional cardiovascular risk factors, 2) serum RANKL and OPG levels, and 3) neuropathy.

PATIENTS AND METHODS

We objectively scored, in a cross-sectional study, infrapopliteal vascular calcification using computed tomography scanning in 198 patients with type 2 diabetes, a high cardiovascular risk, and a glomerular filtration rate >30 mL/min. Color duplex ultrasonography was performed to assess peripheral arterial occlusive disease, and mediacalcosis. Peripheral neuropathy was defined by a neuropathy disability score >6. RANKL and OPG were measured in the serum by routine chemistry.

RESULTS

Below-knee arterial calcification was associated with arterial occlusive disease. In multivariate logistic regression analysis, the variables significantly and independently associated with the calcification score were age (odds ratio [OR] = 1.08; 95% confidence interval [CI] = 1.04-1.13; P < .0001), male gender (OR = 3.53; 95% CI = 1.54-8.08; P = .003), previous cardiovascular disease (OR = 2.78; 95% CI = 1.39-5.59; P = .005), and neuropathy disability score (per 1 point, OR = 1.21; 95% CI = 1.05-1.38; P = .006). The association with ln OPG, significantly associated with calcification score in univariate analysis (OR = 3.14; 95% CI = 1.05-9.40; P = .045), was no longer significant in multivariate analysis. RANKL and OPG/RANKL were not significantly associated with the calcification score.

CONCLUSIONS

Below-knee arterial calcification severity is clearly correlated with peripheral neuropathy severity and with several usual cardiovascular risk factors, but not with serum RANKL level.

Progression of coronary artery calcification in living kidney donors: a follow-up study

BACKGROUND

Data on the long-term mortality and morbidity of living kidney donors are scarce. In the general population, coronary artery calcification (CAC) and progression of CAC are predictors of future cardiac risk. We conducted a study to determine the progression of CAC in renal transplant donors.

METHODS

We used multidetector computed tomography to examine CAC in 75 former renal transplant donors. A baseline and a follow-up scan were performed and changes in CAC scores were evaluated in each subject individually to calculate the incidence of CAC progression.

RESULTS

Baseline CAC prevalence was 16% and the mean CAC score was 5.3 ± 25.8. At the follow-up scan that was performed after an average of 4.8 ± 0.3 years, CAC prevalence increased to 72% and the mean CAC score to 12.5 ± 23.4. Progression of the individual CAC score was found between 18.7 and 26.7%, depending on the method used to define progression. In patients with baseline CAC, the mean annualized rate of CAC progression was 2.1. Presence of hypertension, high systolic blood pressure and an increase in BMI were the determinants of CAC progression.

CONCLUSIONS

The rate of CAC progression does not seem to be high in carefully selected donors.

Circulating vitamin D metabolites and subclinical atherosclerosis in type 1 diabetes

OBJECTIVE

People with type 1 diabetes are at high risk of premature atherosclerosis. Existing evidence suggests that impaired vitamin D metabolism may contribute to the development of atherosclerosis. We tested associations of circulating vitamin D metabolite concentrations with subclinical atherosclerosis among 1,193 participants with type 1 diabetes in the DCCT/EDIC study.

RESEARCH DESIGN AND METHODS

We measured plasma concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D by mass spectrometry at the end of the DCCT. In a staggered cross-sectional design, we tested associations with coronary artery calcium (CAC), measured by computed tomography a median of 10 years later, and with common and internal carotid intima-media thickness (IMT), measured by B-mode ultrasonography on two occasions a median of 4 years later and a median of 10 years later. We hypothesized that lower concentrations of each vitamin D metabolite would be associated with increased risk of CAC and greater carotid IMT. RESULTS At the time metabolites were measured, mean age was 32.4 years and mean duration of diabetes was 7.5 years. The prevalence and severity of CAC tended to be lower-not higher-with lower concentrations of each vitamin D metabolite. For instance, in a fully adjusted multinomial logistic model, a 25 nmol/L lower 25-hydroxyvitamin D was associated with a 0.8-fold decrease in the odds of having higher CAC (95% CI 0.68-0.96, P = 0.01). No vitamin D metabolite was associated with either common or internal mean IMT.

CONCLUSIONS

We did not find evidence linking impaired vitamin D metabolism with increased subclinical atherosclerosis in type 1 diabetes.

Obesity and coronary artery calcium in diabetes: the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study

BACKGROUND

The aim was to examine whether excess weight is associated with coronary artery calcium (CAC), independent of metabolic parameters in adults with type 1 diabetes (T1D).

METHODS

Subjects between 19 and 56 years of age with T1D (n=621) from the Coronary Artery Calcification in Type 1 Diabetes study were classified as abnormal on four metabolic parameters: blood pressure ≥130/85 mm Hg or on antihypertensive treatment; high-density lipoprotein-cholesterol of <40 mg/dL for men or <50 mg/dL for women; triglycerides of ≥150 mg/dL; or C-reactive protein of ≥3 μg/mL. Study participants with two or more abnormal parameters were classified as metabolically abnormal. Weight categories by body mass index were normal (<25 kg/m(2)), overweight (25 to <30 kg/m(2)), and obese (≥30 kg/m(2)). CAC was measured at two visits 6.0±0.5 years apart. Progression of CAC was defined as an increase in square root transformed CAC volume of ≥2.5 mm(3) or development of clinical coronary artery disease.

RESULTS

Among subjects with T1D, 48% of normal, 61% of overweight, and 73% of obese participants were classified as metabolically abnormal (P<0.0001). Overweight and obesity were independently associated with presence of CAC, independent of presence of metabolically abnormal. Obesity but not overweight was associated with CAC progression, independent of the other cardiovascular risk factors.

CONCLUSIONS

Although obesity is known to increase cardiovascular disease risk through inducing metabolic abnormalities such as dyslipidemia, hypertension, and inflammation, it is also a strong predictor of subclinical atherosclerosis progression in adults with T1D independent of these factors.

Predictors of progression in atherosclerosis over 2 years in systemic lupus erythematosus

OBJECTIVES

Cardiovascular disease remains the major cause of death in SLE. We assessed the degree to which cardiovascular risk factors (CVRFs) and disease activity were associated with 2-year changes in measures of subclinical atherosclerosis.

METHODS

One hundred and eighty-seven SLE patients participating in a placebo-controlled trial of atorvastatin underwent multi-detector CT [for coronary artery calcium (CAC)] and carotid duplex [for carotid intima-media thickness (IMT) and carotid plaque] twice, 2 years apart. During the 2 years, patients were assessed every 3 months for CVRF. Both groups were combined for analysis, as atorvastatin did not differ from placebo in preventing progression of coronary calcium. We examined the correlation between these clinical measures and progression of CAC, IMT and plaque during the follow-up period.

RESULTS

In an analysis adjusting for age, gender and ethnicity, CAC progression was positively associated with total serum cholesterol measured over the 2-year period (P = 0.04) and smoking (P = 0.003). Carotid IMT progression was associated with systolic BP (P = 0.003), high-sensitivity CRP (hsCRP) (P = 0.013) and white blood cell (WBC) count (P = 0.029). Carotid plaque progression, defined as patients without carotid plaque at baseline with subsequent development of plaque at follow-up, was associated with systolic BP (P = 0.003), WBC count (P = 0.02), physician's global assessment (P = 0.05), blood lymphocyte count (P = 0.048), urine protein (P = 0.017) and duration of SLE (P = 0.019).

CONCLUSION

Our data did not provide evidence of an association between measures of SLE disease activity (SLEDAI, anti-dsDNA, anti-phospholipid and treatment) and progression of subclinical atherosclerosis. Age and hypertension were associated with the progression of carotid IMT and plaque. Age, smoking and cholesterol were associated with progression of CAC.

Progression of coronary artery calcium in men affected by human immunodeficiency virus infection

Cardiovascular risk is increased in HIV infected patients. We assessed progression of coronary artery calcium (CAC) in patients with HIV infection to identify factors that may help explain progression of atherosclerosis. Prospective, observational study of 132 HIV-infected men receiving chronic antiretroviral therapy (ART); we measured traditional atherosclerosis risk factors and assessed progression of CAC on sequential 64-slice CT scans at an average interval of 11 months (range 6-36). CAC score progression was defined as absolute and percentage change from baseline. During follow-up 45 patients (34%) showed absolute progression of CAC and 34 of them showed >15% yearly progression, a threshold previously associated with a high risk of myocardial infarction. Age, LDL cholesterol, visceral abdominal fat and current T-helper (CD4+) cell count were significantly associated with absolute CAC progression. Progression of subclinical atherosclerosis in HIV patients is associated with traditional coronary risk factors as well as HIV related factors such as the CD4+ cell count. Therefore, immunologic perturbations secondary to HIV infection may contribute to atherosclerosis progression.

Relationship between cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC) in patients with type 2 diabetes mellitus

Early detection of atherosclerosis is important for patients with type 2 diabetes mellitus because cardiovascular disease (CVD) is a main cause of death in these people. In this study, we investigated the relationship between an arterial stiffness parameter called cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC). We performed a cross-sectional study in 371 type 2 diabetic patients with clinical suspicion of coronary heart disease (CHD). We evaluated the relationships between CAVI and CAC score determined by multislice computed tomography as well as major cardiovascular risk factors, including age, body mass index, hemoglobinA1c and the Framingham CHD risk score. CAVI was correlated with age (r = 0.301, p < 0.0001), uric acid (r = 0.236, p < 0.0001), estimated glomerular filtration rate (r = -0.145, p = 0.0166), CHD risk score (r = 0.327, p < 0.0001) and log (CAC + 1) (r = 0.303, p < 0.0001). The area under the receiver operating characteristic curve for CAVI was higher than that of CHD risk score in predicting CAC >0, CAC >100, CAC >400, or CAC >1000. CAVI is positively correlated with CAC, and is considered to be a useful method to detect CAC.

Rates and determinants of coronary and abdominal aortic artery calcium progression in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE

To determine the predictors of progression of calcified atherosclerosis and the effect of intensive glycemic control on this process in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

As part of the Risk Factors, Atherosclerosis, and Clinical Events in Diabetes (RACED) substudy of the Veterans Affairs Diabetes Trial (VADT), 197 and 189 individuals with type 2 diabetes received baseline and follow-up computed tomographic scans for measurement of coronary and abdominal artery calcium, respectively. Standard and novel risk factors were assessed at baseline, and progression of calcified atherosclerosis was determined by several methods. Progression was defined both as a categorical (square root increase of volumetric scores ≥ 2.5 mm(3)) and continuous variable. In addition, annualized percent change of volume scores was determined.

RESULTS

After an average follow-up of 4.6 years, >75% of individuals demonstrated coronary (CAC) and abdominal artery calcification (AAC) progression. Progression increased with higher baseline calcium categories but was not influenced by standard risk factors. However, the albumin-to-creatinine ratio (ACR) (P = 0.02) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) (P = 0.01) predicted progression of CAC, and these results were not altered by adjustment for age and other traditional risk factors. Treatment assignment (intensive versus standard) within the VADT did not influence CAC or AAC progression, irrespective of baseline calcium category.

CONCLUSIONS

In patients with long-standing type 2 diabetes, baseline CAC, Lp-PLA(2), and ACR predicted progression of CAC. Intensive glycemic control during the VADT did not reduce progression of calcified atherosclerosis.

Glycaemic variability is associated with coronary artery calcium in men with Type 1 diabetes: the Coronary Artery Calcification in Type 1 Diabetes study

AIMS

We investigated coronary artery calcium in association with glucose levels and variability measured using continuous glucose monitoring in adults with Type 1 diabetes in the Coronary Artery Calcification in Type 1 Diabetes study.

METHODS

Coronary artery calcium was measured by electron beam tomography. The presence of any coronary artery calcium was analysed with respect to glucose levels [mean(T) (mean glucose), % of values < 3.9 mmol/l, > 10 mmol/l and either < 3.9 or > 10 mmol/l] and glycaemic variability [sd(T) (sd of all glucose values); sd(dm) (sd of the daily mean glucose levels) and sd(hh:mm) (glucose sd for a specified time of day, over all days)] using 3-5 days of continuous glucose monitoring from 75 subjects (45 women, 30 men), age 42 ± 9 years (mean ± sd) and diabetes duration of 29 ± 8 years using logistic regression.

RESULTS

We observed significant associations between coronary artery calcium and mean(T) (OR = 4.4, 95% CI 1.1-18.6), % of values > 10 mmol/l (OR = 5.5, 95% CI 1.3-22.6), % of measures < 3.9 or > 10 mmol/l (OR = 5.7, 95% CI 1.3-24.9), sd(T) (OR = 4.7, 95% CI 1.1-19.7), sd(dm) (OR = 6.0, 95% CI 1.2-30.4) and sd(hh:mm) (OR = 4.0, 95% CI 1.1-15.4), among men, but none of these variables were associated with the presence of coronary artery calcium in women.

CONCLUSIONS

We report the novel finding that subclinical atherosclerosis is associated with glucose levels and variability in men with Type 1 diabetes. The relationship of coronary artery calcium and glucose variability in Type 1 diabetes, and potential gender differences in this association, deserve further study.

Association between coronary artery calcification progression and microalbuminuria: the MESA study

OBJECTIVES

This study sought to evaluate the relationship between microalbuminuria (MA) and the development and progression of atherosclerosis, as assessed by incident and progression of coronary artery calcification (CAC).

BACKGROUND

MA is associated with an increased risk of cardiovascular disease, but the mechanism by which MA imparts this increased risk is not known.

METHODS

The MESA (Multi-Ethnic Study of Atherosclerosis) study is a prospective cohort study of 6,814 self-identified White, African-American, Hispanic, or Chinese participants free of clinical cardiovascular disease at entry. Of the 6,775 individuals with available urine albumin data, we excluded 97 subjects with macroalbuminuria and 1,023 with missing follow-up CAC data. The final study population consists of 5,666 subjects.

RESULTS

At baseline, individuals with MA were more likely to have CAC >0 compared with those without MA (62% vs. 48%, p < 0.0001). During a mean follow-up of 2.4 +/- 0.8 years, those with MA and no CAC at baseline were more likely to develop CAC (relative risk [RR]: 2.05, 95% confidence interval [CI]: 1.41 to 3.02, p < 0.0001) as compared with those without MA in demographic-adjusted analyses. After multivariant adjustment, the relationship was attenuated but remained statistically significant (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005). Among those with CAC at baseline, those with versus those without MA had a 15 (95% CI: 8 to 22, p < 0.0001) volume units higher median increase in CAC in demographic-adjusted analyses. After multivariant adjustment, MA remained associated with incident CAC (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005) and with progression of CAC (median increase in CAC volume score of 9 [95% CI: 2 to 16, p = 0.009]), relative to those without MA.

CONCLUSIONS

This large multiethnic, population-based study of asymptomatic individuals demonstrates an increased risk of incident CAC as well as greater CAC progression among those with MA. Further study is needed to determine the degree to which MA precedes and predicts progression of atherosclerosis and how this information can be used to reduce cardiovascular events.

Pulse wave analysis and prevalent cardiovascular disease in type 1 diabetes

OBJECTIVE

Type 1 diabetes (T1D) is associated with a high risk for and mortality from premature coronary artery disease (CAD), including coronary artery calcification (CAC), a subclinical marker, and lower extremity arterial disease (LEAD). Pulse wave analysis (PWA) arterial stiffness indices have been associated with cardiovascular disease (CVD) risk factors and outcomes in various populations, but little is known regarding these relationships in T1D.

METHODS

PWA was performed using the SphygmoCor Px device on 144 participants in the Pittsburgh EDC Study of childhood-onset T1D. The cross-sectional associations between arterial stiffness indices, augmentation index (AIx) and augmentation pressure (AP), and subendocardial viability ratio (SEVR), an estimate of myocardial perfusion, with prevalent CAD, electron beam computed tomography-measured CAC and low (<0.90) ankle-brachial index (ABI) were examined.

RESULTS

Higher AP (but not AIx) and lower SEVR were univariately associated with prevalent CAD, high CAC score, and low ABI. AP and SEVR's association with CAD and CAC did not, however, remain significant after adjustment for age. In individuals not using nitrates, which profoundly affect PWA measures, AP was significantly higher in those with CAD events and explained more of the variance than either age or brachial blood pressure measures. SEVR was associated with low ABI in multivariable models.

CONCLUSIONS

Greater augmentation pressure is independently associated with prevalent CAD and estimated myocardial perfusion with low ABI in type 1 diabetes. These measures may thus help to better characterize CVD risk in type 1 diabetes and need to be examined prospectively.

Free fatty acids are associated with pulse pressure in women, but not men, with type 1 diabetes mellitus

Cardiovascular disease (CVD) is the leading cause of death in type 1 diabetes mellitus (T1D). Pulse pressure, a measure of arterial stiffness, is elevated in T1D and associated with CVD. Free fatty acids (FFAs), elevated in women and abdominal adiposity, are also elevated in T1D and CVD. We thus examined the association of fasting FFAs with pulse pressure and coronary artery calcification (CAC, a marker of coronary atherosclerotic burden) in an adult population (n = 150) of childhood-onset T1D and whether any such associations varied by abdominal adiposity and sex. Mean age and diabetes duration were 42 and 33 years, respectively, when CAC, visceral abdominal adiposity (VAT), and subcutaneous abdominal adiposity (SAT) were determined by electron beam tomography. Free fatty acids were determined by in vitro colorimetry. Pulse pressure was calculated as systolic blood pressure minus diastolic blood pressure. Free fatty acids were log transformed before analyses, and all analyses were controlled for serum albumin. Free fatty acids were associated with pulse pressure in women (r = 0.24, P = .04), but not in men (r = 0.07, P = .55). An interaction for the prediction of pulse pressure was noted between FFAs and both VAT (P = .03) and SAT (P = .008) in women, but only a marginal interaction with SAT (P = .09) and no interaction for VAT (P = .40) with FFAs were observed in men. In multivariable linear regression analysis allowing for serum albumin, age, height, heart rate, albumin excretion rate, hemoglobin A(1c), high-density lipoprotein cholesterol, hypertension medication use, FFAs, SAT, and the interaction between FFAs and SAT, the interaction between FFAs and SAT remained associated with pulse pressure in women (FFAs, P = .04; interaction term, P = .03), but not men (FFAs, P = .32; interaction term, P = .32). FFAs showed no association with log-transformed CAC. Although FFAs were not associated with CAC in either sex, they were associated with pulse pressure in women and their effect appeared to vary by abdominal adiposity, particularly SAT. This finding might help explain the loss of the sex difference in CVD in T1D.

Insulin resistance independently predicts the progression of coronary artery calcification

BACKGROUND

Change in coronary artery calcification is a surrogate marker of subclinical coronary artery disease (CAD). In the only large prospective study, CAD risk factors predicted progression of coronary artery calcium (CAC).

METHODS

We measured CAC at enrollment and after 24 months in a community-based sample of 869 healthy adults aged 60 to 72 years who were free of clinical CAD. We assessed predictors of the progression of CAC using univariate and multivariate models after square root transformation of the Agatston scores. Predictors tested included age, sex, race/ethnicity, smoking status, body mass index, family history of CAD, C-reactive protein and several measures of diabetes, insulin levels, blood pressure, and lipids.

RESULTS

The mean age of the cohort was 66 years, and 62% were male. The median CAC at entry was 38.6 Agatston units and increased to 53.3 Agatston units over 24 months (P < .01). The CAC progression was associated with white race, diabetes, dyslipidemia, hypertension, lower diastolic blood pressure, and higher pulse pressure. After controlling for these variables, higher fasting insulin levels independently predicted CAC progression.

CONCLUSIONS

Insulin resistance, in addition to the traditional cardiac risk factors, independently predicts progression of CAC in a community-based population without clinical CAD.

Glycemia and cardiovascular disease in type 1 diabetes mellitus

OBJECTIVE

To evaluate the role of glycemic control in the development of cardiovascular disease (CVD) in type 1 diabetes mellitus (DM).

METHODS

We review the literature regarding coronary atherosclerosis, coronary artery calcification, and the epidemiologic studies related to the role of glycemia and the classic risk factors for coronary artery disease (CAD) in type 1 DM.

RESULTS

Four prospective studies (Wisconsin Epidemiologic Study of Diabetic Retinopathy, EURODIAB, Steno Diabetes Center Study of Adults With Type 1 DM, and Pittsburgh Epidemiology of Diabetes Complications study) do not show that glycemic control predicts CAD occurrence. Findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study show that compared with conventional insulin therapy, intensive insulin therapy reduces CVD among patients with type 1 DM and is associated with lower prevalence of coronary artery calcification. The discrepancies between the findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study and the Pittsburgh Epidemiology of Diabetes Complication study are likely due to differences between the study populations and the lower prevalence of renal disease in the former study. Besides duration of DM and albuminuria/overt nephropathy, insulin resistance is a major determinant of CAD associated with type 1 DM.

CONCLUSIONS

Discrepant study results regarding the relationship between glycemia and CAD/coronary artery calcification may be related to the prevalence of renal disease and the presence of the metabolic syndrome. Published data suggest that addressing traditional risk factors including albuminuria, the metabolic syndrome, and inflammatory markers is better for preventing and treating CAD than focusing exclusively on glycemic control, which is still necessary for preventing microvascular complications. Furthermore, there is a synergistic effect of glycemic control and albuminuria on the development of CVD.

[Cardiovascular disease in type 1 diabetes mellitus]

The association between type 1 diabetes and coronary heart disease has become very clear since the late 1970. It has been demonstrated that there is an important increased risk in morbidity and mortality caused by coronary artery disease in young adults with type 1 diabetes compared with the non diabetic population. The underlying pathogeneses is still poorly understood. While the role of glycemic control in the development of microvascular disease complication is well established its role in CVD in patients with DM1 remains unclear with epidemiologic studies reporting conflicting data. Recent findings from the DCCT/EDIC showed that prior intensive diabetes treatment during the DCCT was associated with less atherosclerosis, largely because of reduced level of HbA1c during the DCCT. The improvement of glycemic control itself appeared to be particularly effective in younger patients with shorter duration of the disease. Other analyses suggested the glycemia may have a stronger effect on CAD in patients without than in those with albuminúria. Other major determinants of coronary artery disease are the components of metabolic syndrome and the surrogate measure of insulin resistence: eGDR. It is proposed that patients with DM1 should have aggressive medical therapy, risk factor modification and careful monitoring not only of his blood sugar but also of the other processes involved in the atherosclerotic process, mostly the ones with family history of type 2 diabetes.

Type 1 diabetes, hyperglycaemia, and the heart

Type 1 diabetes is associated with a substantially increased risk of cardiovascular disease that might not always be appreciated in view of the fairly young age of patients with this condition. In fact, in type 1 diabetes, the heart is subject to a variety of pathological insults, including accelerated atherosclerosis, cardiac autonomic neuropathy, and possibly intrinsic cardiomyopathy. Although the relation between hyperglycaemia and microvascular complications has been well established, a direct effect of hyperglycaemia on cardiovascular disease in type 1 diabetes has long been debated. More recently, several studies, most notably the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications, have clarified this issue and provided conclusive evidence that hyperglycaemia is indeed a mediator of cardiovascular risk in type 1 diabetes and that intensive diabetes therapy can reduce cardiovascular disease outcomes. We review current concepts in type 1 diabetes and the heart, focusing on recent insights into the central role of hyperglycaemia.