Serum lipids and apolipoproteins and their relationship with macrovascular disease in type 1 diabetes

Lipid profile and correlation to cardiac risk factors and cardiovascular function in type 1 adolescent diabetics from a developing country

Objective. The adverse role of dyslipidemia in predicting cardiovascular outcomes has not been elucidated extensively among type 1 diabetics in the literature. Methods. We assessed dyslipidemia and its correlation to other cardiac risk factors in adolescents with type 1 diabetes. Total thirty type 1 adolescent diabetics were evaluated for their metabolic profile, including serum lipids and echocardiography was performed. Results. The average age of the cohort was 14.3 ± 3.09 yr with disease duration of 5.35 ± 2.94 yr. The mean HbA1C was 8.01%. The mean serum cholesterol, LDL, HDL, and triglyceride were normal. Serum cholesterol was high in patients with longer disease duration (P = 0.011, r = 0.41), high systolic blood pressure (P = 0.04, r = 0.32), and elevated HbA1C > 8% (P = 0.038, r = 0.33). Higher lipid values were associated with poorer carotid artery distensibility (P > 0.05) and higher carotid artery intimomedial thickness (cIMT) (P < 0.05 for cholesterol and LDL). Hyperglycemia adversely affected ejection fractions, though serum lipids did not show any significant effect on left ventricular parameters. Conclusions. Dyslipidemia and hyperglycemia can serve as biomarkers for cardiovascular dysfunction in at-risk adolescents with type 1 diabetes. Carotid artery parameters are adjunctive tools which may be affected early in the course of macrovascular disease.

Are Your Arteries Older Than Your Age?

PURPOSE

To determine the effect of age and atherosclerotic risk factors on the carotid intima-media layer thickness and morphology characteristics.

PATIENTS AND METHODS

Three groups of subjects were included in the study: Individuals with atherosclerotic risk factors including a family history of CHD, hypertension, hyperlipidemia, diabetes, and/or smoking (group A, n=180), age- and sex-matched healthy subjects without risk factors (group B, n=60) and a group of significantly younger volunteers (group C, n=25). The carotid artery was imaged longitudinally with B-mode ultrasound. Intima media thickness (IMT) was measured in the common (CCA) and internal carotid (ICA) arteries. Surface irregularity and continuity of the intima-media layer (IML) were assessed by high definition imaging. Echogenicity of the wall was quantified using Adobe Photoshop. The presence of calcium deposits was recorded. The double line wall pattern seen in young healthy people was used as a control to assess patterns and texture of the carotid IML. Fifteen subjects had their measurements repeated for intraobserver variability.

RESULTS

IMT measurements were reproducible in both the CCA and ICA (coefficient of variation 6% and 9%). IMT increased linearly with age (adjusted R(2)=0.72, p<0.0001), which was also an independent risk factor for increased IMT. All the risk factors had a significant association with increased IMT. In the lowest (third) decade the wall/blood interface was smooth and the double line was visualized with an echolucent center. With increased age and number of risk factors present, the wall/blood interface became more irregular (p<0.01), the double line was distorted (p<0.01) and the IML was more echogenic (p<0.01). The increase in IMT and the changes in the echogenicity of the IML were more pronounced in the ICA.

CONCLUSIONS

Age is an independent risk factor for increased IMT. Atherosclerotic risk factors are associated with the age-related changes seen in the IML. Such changes are also seen in younger asymptomatic volunteers with risk factors indicating that their arteries are older than their age.

High cumulative insulin exposure: a risk factor of atherosclerosis in type 1 diabetes?

BACKGROUND

Since insulin therapy might have an atherogenic effect, we studied the relationship between cumulative insulin dose and atherosclerosis in type 1 diabetes. We have focused on patients with type 1 diabetes instead of type 2 diabetes to minimise the effect of insulin resistance as a potential confounder.

METHODS

An observational study was performed in 215 subjects with type 1 diabetes treated with multiple insulin injection therapy. Atherosclerosis was assessed by measurement of carotid intima-media thickness (CIMT).

RESULTS

The cumulative dose of regular insulin showed a positive and significant relation with CIMT: increase of 21 microm in CIMT per S.D. of insulin use (95% CI: 8-35 adjusted for gender and age), which remained unchanged after adjustment for duration of diabetes, HbA1c, BMI, pulse pressure, physical activity and carotid lumen diameter. A similar relation was found for intermediate-acting insulin: 15.5 microm per S.D. (2-29), which was no longer present after further adjustment.

CONCLUSIONS

These findings provide evidence that a high cumulative dose of regular insulin is a risk factor for atherosclerosis.

Glycaemic control and familial factors determine hyperlipidaemia in early childhood diabetes. Oxford Regional Prospective Study of Childhood Diabetes

AIMS

To determine whether abnormal lipid levels in children with Type 1 diabetes mellitus are the result of poor metabolic control or may in part be determined by genetic factors.

METHODS

Non-fasting lipid levels were measured in 141 children with Type 1 diabetes (age range 7.7-19 years) 3 years after diagnosis, and in 192 of their parents. Glycosylated haemoglobin and the urinary albumin-creatinine ratio (three urine samples) were estimated in each child annually.

RESULTS

The children had a mean total cholesterol of 4.46 +/- 1.25 mmol/l (+/- SD) and a median triacylglycerol of 1.18 mmol/l (range 0.32-4.7). A total of 15.3% of the population had a total cholesterol > 5.2 mmol/l and 17.9% had a triacylglycerol > 1.7 mmol/l; in 5.6% both total cholesterol and triacylglycerol were greater than these cut-off points. Total cholesterol, triacylglycerol and very low density lipoprotein-cholesterol were significantly correlated to glycaemic control. However, total cholesterol was also significantly related to parental total cholesterol either as analysed separately or as mean parental total cholesterol (r = 0.37, P = 0.0001). In stepwise multiple regression analysis both mean parental total cholesterol (P = 0.001) and HbA1c (P = 0.015) were significant determinants of the child's total cholesterol. The children studied were being followed prospectively for the development of microalbuminuria and there was a weak association across tertiles of total cholesterol, linking higher levels to the development of microalbuminuria (P < 0.05).

CONCLUSIONS

We conclude that both glycaemic control and familial factors may be important determinants of lipid levels in young people with diabetes. Both may contribute to the subsequent risk of cardiovascular disease and possibly the development of incipient diabetic nephropathy.