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Macrovascular Residual Risk THROUGH LANDMARK STUDY

5 January 2013
Atherogenic dyslipidemia and arterial stiffness in young subjects

The ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) is an independent determinant of arterial stiffness, indicative of early atherosclerosis, in adolescents and young adults, according to a study in nearly 900 subjects. These findings imply that the use of the TG/HDL C ratio may help to identify young subjects at high risk of accelerated atherosclerosis.

Triglyceride to HDL-C ratio and increased arterial stiffness in children, adolescents, and young adults. Pediatrics;131:e1082-90.
Urbina EM, Khoury PR, McCoy CE, Dolan LM, Daniels SR, Kimball TR.
Summary
Comments & References
STUDY SUMMARY
Objective: To investigate whether the TG/HDL-C ratio is an independent predictor of arterial stiffness, a measure of early atherosclerosis, in otherwise healthy young adults and adolescents
Study design: Pooled data from two population studies
Study population:

893 subjects aged 10-26 years (mean 18.9 years, 39% male, 56% non-Caucasian, mainly African-American). Subjects with diabetes, female subjects who were pregnant and individuals with chronic disease or taking medication affecting carbohydrate metabolism were excluded. All subjects had nondiabetic fasting glucose or normal oral glucose tolerance, as per the American Diabetes Association guidelines.1

Primary variables:

• Arterial stiffness, based on brachial arterial distensibility, augmentation index and carotid-femoral pulse wave velocity measurements
• TG/HDL-C

Methods:

Anthropometric, blood pressure, laboratory and arterial stiffness data were measured after subjects had fasted for 10 hours. The TG/HDL-C ratio was categorised based on race-specific tertiles for subjects with body mass index (BMI) <85th percentile (Table 1). Non-invasive vascular function measurements were the mean of three recordings.

Table 1. Race-specific tertiles for TG/HDL-C ratio

 

Low

Mid

High

Whites

0.83 to <1.28

1.28 to <1.92

³1.92

Blacks

0.78 to <0.90

0.90 to <1.40

³1.40


General linear models were used to investigate if TG/HDL-C was an independent determinant of arterial stiffness. The model included TG/HDL-C, age, anthropometric data, mean arterial pressure, heart rate (except for augmentation index), low-density lipoprotein cholesterol (LDL-C), C-reactive protein, glucose and insulin.
Main results:

There was a progressive increase in arterial stiffness across the TG/HDL-C ratio (Table 2). Arterial stiffness was greatest in the group with high TG/HDL-C ratio. In models adjusted for cardiovascular risk factors, the TG/HDL-C ratio was an independent determinant of arterial stiffness, especially in overweight subjects.

Table 2. Lipids and arterial stiffness by TG/HDL-C ratio*


Variable

Low TG/HDL-C (N=227)

Mid TG/HDL-C
(N=288)

High TG/HDL-C
(N=378)

Lipids (mg/dL)

 

 

 

LDL-C

82 (23)

94 (25)

104 (28)

HDL-C

64 (14)

54 (10)

45 (9)

TG

50 (14)

71 (19)

116 (51)

TG/HDL-C

0.8 (0.2)

1.3 (0.3)

2.7 (1.6)

Augmentation index, %

-1.16 (12.11)

0.60 (11.04)

1.72 (11.11)

Brachial distensibility, %/mmHg

6.76 (1.23)

6.37 (1.26)

5.89 (1.23)

Pulse wave velocity, m/sec

5.60 (0.90)

5.84 (0.87)

6.13 (1.09)


* Mean (SD)

Authors’ conclusion: The use of the TG/HDL-C ratio may be helpful in identifying young adults at an early stage of atherosclerosis who may require intervention to prevent atherosclerotic vascular disease.

COMMENT

Arterial stiffness is a hallmark of early atherosclerosis and a marker for increased cardiovascular disease risk. A complex interaction of changes involving structural and cellular elements of the vessel wall underlies its pathogenesis. Chronic conditions including diabetes mellitus, as well as aging itself, amplify these vascular changes.2

Previous studies have shown an association between TG, HDL-C and arterial stiffness in adults with the metabolic syndrome.3,4 However, information has been lacking for the association of these defining components of atherogenic dyslipidemia to vascular measures in younger subjects.

This study, based on a large sample of nearly 900 subjects, is the first to show that the TG/HDL-C ratio is independently predictive of arterial stiffness in a seemingly healthy adolescent and young adult population. These findings have important implications in the light of the ongoing obesity epidemic, especially among younger individuals, who would be anticipated to exhibit a high prevalence of atherogenic dyslipidemia. Indeed, recent US guidelines have highlighted the importance of screening for dyslipidemias, including elevated TG, in young subjects.5 Computing a ratio from fasting TG (numerator) and fasting HDL-C (denominator) allows for grading atherogenic dyslipidemia as a continuous variable. The results of this study suggest that the TG/HDL-C ratio is an accessible screening measure that may provide incremental information over plasma TG alone, in identifying young subjects at risk of accelerated atherosclerosis who warrant aggressive intervention to improve long-term CV outcomes.

References

1. American Diabetes Association. Standards of medical care in diabetes-2013. Diabetes Care 2013; 36 (Supplement 1): S11-S66.
2. Zieman SJ, Melenovsky V, Kass DA. Mechanisms, pathophysiology, and therapy of arterial stiffness. Arterioscler Thromb Vasc Biol 2005;25:932-43.
3. Roes SD, Alizadeh Dehnavi R, Westenberg JJM et al. Assessment of aortic pulse wave velocity and cardiac diastolic function in subjects with and without the metabolic syndrome: HDL cholesterol is independently associated with cardiovascular function. Diabetes Care 2008;31:1442–4.
4. Legedz L, Bricca G, Lantelme P et al. Insulin resistance and plasma triglyceride level are differently related to cardiac hypertrophy and arterial stiffening in hypertensive subjects. Vasc Health Risk Manag 2006;2:485–490.
5. Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents. Summary Report. Pediatrics 2011;128 Suppl 5:S213–56.

Key words

TG/HDL-C ratio; atherogenic dyslipidemia; arterial stiffness, early atherosclerosis; young subjects