죽상동맥경화증의 위험인자로서 경동맥 내중막 두께에 대한 공복혈당장애의 역할

Abstract

Background: The Expert Committee of the American Diabetes Association(ADA) proposed a new category, but that was similar to the imparied glucose tolerance(IGT), that being the impaired fasting glucose(IFG). It was confirmed that the IGT is a fatal risk factor associated with cardiovascular disease. However, it is not know whether the IFG is a risk factor for atherosclerosis, as is IGT. In this study, we investigated the role of the IFG on the carotid artery intima-media thickness(IMT) as a risk factor for atherosclerosis.

Methods: The analyses were based on the data abtained from the medical checkups of 944 subjects. Subjects with a previous history of coronary heart disease or cerebral vascular disease, or who had been treated with antihypertensive of hypolipidemic agents, were excluded. For the analysis, the classifications of diabetes and IFG were based on the recent ADA recommendations. Diabetes was diagnosed on the basis of a fastion plasma glucose(FPG) ≥ 7.0 m㏖/ℓ, or current treatment with oral hypoglycemic agents or insulin. IFG was defined as a FPG ≥ 6.1 m㏖/ℓ but < 7.0 m㏖/ℓ, and a normal glucose tolerance(NGT) as a FPG < 6.1 m㏖/ℓ. The body mass index(BMI), waist-to-hip ratio(WHR), systolic and diastolic blood pressures(SBP and DBP), serum fasting glucose, insulin, total cholesterol, triglyceride and HDL-cholesterol were measured in all participants. High-resolution B-mode ultrasonography was performed to determine the mean and maximal carotid IMT.

Results: 1) There were significant differences in the age, WHR and triglyceride between the NGT, IFG, and diabetic groups. 2) After adjustment of age, sex, smoking history(packs/year), BMI, WHR, SBP, DBP, serum triglyceride, and HDL-cholesterol, the mean carotid IMT was significantly increased in the diabetic group(0.77±0.20 ㎜) compared to the NGT(0.66±0.16 ㎜, P<0.001) and IFG(0.68±0.20 ㎜ p<0.05) groups. The maximal carotid IMT was significantly increased in the diabetic group compared to the NGT group (0.84±0.26 ㎜ vs. 0.71±0.20 ㎜, p<0.01), but not the IFG group(0.74±0.30 ㎜, p=0.07). However, there were no significant association between the IFG and NGT groups in terms of the mean or maximal carotid IMT.

3) We divided all the participants, which no history of diagnosis or treatment for diabetes, into five classes according to their fasting glucose levels (Class Ⅰ: ≤ 4.72 m㏖/ℓ, class Ⅱ: >4.72 m㏖/ℓ and 5.5 m㏖/ℓ, class Ⅲ: >5.5 m㏖/ℓ and < 6.1 m㏖/ℓ, class Ⅳ : ≥ 6.1 m㏖/ℓ and < 7.0 m㏖/ℓ, and class Ⅴ: ≥ 7.0 m㏖/ℓ). After adjusting for age, sex, smoking history, BMI, WHR, SBP, DBP, triglyceried and HDL-cholesterol, the mean carotid IMT in class Ⅴ was significantly increased compared to those in classes Ⅰ,Ⅱ and Ⅲ (0.74±0.15 ㎜ vs 0.65±0.15 ㎜, 0.67±0.16 ㎜ and 0.68±0.15 ㎜, p<0.05, respectively). The maximal carotid IMT for class Ⅴwas significantly increased compared to classes Ⅰand Ⅱ(0.79±0.17 ㎜ vs. 0.69±0.17 ㎜ and 0.73±0.17 ㎜, p<0.05, respectively). However, there were no significant differences in both the mean and maximal carotid IMT in class Ⅳ compared to the IFG and the other classes.

4) In the five classes above, we assessed the insulin resistance using the HOMA method. The insulin resistance in class Ⅴ(4.23±2.38) was significantly increased compared to classes Ⅰand class Ⅱ which were 1.84±1.05 and 2.48±1.60(p<0.001), respectively. In classes Ⅲ and Ⅳ, the insulin resistances were 3.42±2.60 and 3.31±1.89, respecitvely, which were higher than classes Ⅰ(p<0.001) and Ⅱ(p<0.001 and p<0.05, respectively).

Conclusion: There were significant differences between the diabetic and NGT groups for the mean and maximal IMT. However, for the IFG group, there were no significant differences with respect to the mean and maxima IMT compared to the NGT or diabetic groups. Therefore, IFG may not be a risk factor for atherosclerosis, but as the FPG level was increased, the insulin resistance also increased. Therefor subjects with normal fasting blood glucose levels, which have risk factors for atherosclerosis, need to be thoroughly screened by oral glucose tolerance tests to exclude the possibility of IGT, a risk factor of cardiovascular disease.