Lack of association of insulin resistance and carotid intimal medial thickness in non-diabetic Asian Indian subjects.
OBJECTIVE
Atherosclerosis is associated with insulin resistance (IR) and dyslipidaemia. Impaired glucose tolerance (IGT) is characterised by IR and is associated with a higher risk of atherosclerosis. The objective of the present study was to test whether early atherosclerosis indicated by intimal medial thickness (IMT) of common carotid artery (CCA) and internal carotid artery (ICA) is higher in IGT than in normoglycaemic subjects (NGT) and to look for an association of IMT with IR and dyslipidaemia.


METHODS
Ninety-nine randomly selected non-diabetic subjects aged >or=35 years (48 NGT and 51 IGT) were studied. Measurements of body mass index (BMI), waist/hip ratio (WHR), blood pressure, cholesterol-total, HDL, LDL, VLDL, triglycerides (TG), lipoprotein (a), apolipoprotein-A1 (Apo A1) and apolipoprotein-B (Apo B) and ratio of Apo A1/Apo B were estimated. Insulin resistance (HOMA-IR) was calculated using the fasting plasma insulin and glucose values. IMT of CCA and ICA were measured using high-resolution beta-mode ultrasonography.


RESULTS
Subjects with IGT and NGT were matched for BMI and WHR; HOMA-IR was higher in IGT vs NGT (7.92+/-4.2 vs 6.07+/-3.76, p = 0.028). Age-adjusted IMT values were similar in NGT and IGT (CCA 0.59+/-0.17 and 0.63+/-0.22 mm and ICA 0.44+/-0.10 and 0.45+/-0.10 mm, respectively). Further analyses were done in the total group. Multiple linear regression analyses showed that CCA-IMT was significantly associated with age and negatively associated with Apo A1/Apo B ratio. ICA-IMT was associated with age only. IMT was significantly correlated with cholesterol-total and LDL-cholesterol and apolipoproteins. It was not associated with IR.


CONCLUSIONS
In southern Indians, IGT did not influence the IMT. Although insulin resistance was higher in IGT, it was not associated with higher IMT. Conventional risk factors such as cholesterol, LDL-cholesterol and apolipoproteins showed association with IMT in the insulin-resistant population.
Snehalatha
C
C
Diabetes Research Centre, Royapuram, Madras, India.
Vijay
V
V
Suresh Mohan
R
R
Satyavani
K
K
Sivasankari
S
S
Megha
T
T
Radhika
S
S
Ramachandran
A
A
D000328:Adult; D001774:Blood Chemical Analysis; D001786:Blood Glucose / Q000032:analysis; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000502:physiology*; D005951:Glucose Tolerance Test; D006801:Humans; D007194:India; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008875:Middle Aged; D018709:Statistics, Nonparametric; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000502:physiology*; D014463:Ultrasonography
D001786:Blood Glucose; D007328:Insulin