Insulin resistance and not BMI is the major determinant of early vascular impairment in patients with morbid obesity.

AIM: Several factors contribute to the development of atherogenesis in patients with obesity. The aim of our study was to evaluate the different roles of insulin resistance, strictly correlated to visceral adiposity, and the body mass index (BMI), an estimate of overall adiposity, on early vascular impairment in patients with morbid obesity. METHODS: We enrolled 65 morbidly obese subjects (BMI 44.6 ± 7 kg/m(2)) who were free of previous cardiovascular events and 28 nonobese subjects (control group) in a cross-sectional study. The presence of glycemia and insulinemia, the levels of lipids and liver parameter and the ultrasonographic assessment of the flow-mediated dilatation (FMD), carotid intima-media thickness (IMT) and visceral fat area (VFA) were evaluated in all subjects. RESULTS: In the obese patients with a median HOMA value of ≥ 3.5, the FMD was significantly lower (p < .05) and the left carotid maximum-IMT was significantly higher (p < .05) than those observed in the group with lower HOMA values. No vascular differences were found between the two groups that were subdivided according to the BMI median value. Both the left max-IMT and FMD exhibited a significant correlation with HOMA-IR ("ρ" .292, p=0.02 , "ρ"-.292, p=0.02 respectively) but not with BMI. According to a multivariate analysis, the VFA was an independent predictor of a reduced FMD (ß - .541, p.002; p of the model .002), while age (ß .611 p < .0001) and HOMA-IR (ß .399 p < .001) were independent predictors of the left max-IMT (p of the model .002). CONCLUSIONS: The HOMA-IR, which is strictly related to visceral fat and is an index of metabolic impairment, and not BMI, which reflects of global adiposity, can be used to identify early vascular impairment in patients with morbid obesity.

Association of parathyroid hormone and 25-OH-vitamin D levels with arterial stiffness in postmenopausal women with vitamin D insufficiency.

AIM: Vitamin D insufficiency and increased parathyroid hormone (PTH) levels have been suggested as prognostic indices for cardiovascular disease. Arterial stiffness, a surrogate marker for cardiovascular disease, is often increased in patients with primary hyperparathyroidism. PTH levels increase in patients with low 25-OH-vitamin D levels, but the influence of such an increase on arterial stiffness has not been investigated in postmenopausal women with reduced 25-OH-vitamin D levels. We therefore investigated the association between PTH and aortic stiffness in postmenopausal women with reduced 25-OH-vitamin D levels. METHODS: One hundred fifty postmenopausal women with 25-OH-vitamin D insufficiency (<30 ng/mL) were recruited. Aortic pulse wave velocity (aPWV), a measure of arterial stiffness, PTH and 25-OH-vitamin D levels were measured. Cardiovascular risk factors and markers of bone formation were evaluated. RESULTS: The 25-OH-vitamin D levels were associated with aPWV (rho=-0.23, p=0.006), but the association was not significant when controlling for PTH. Significant correlates of aPWV included age, body mass index, mean arterial pressure and PTH (rho=0.39, p<0.001). Arterial stiffness was predicted by logarithmically transformed PTH levels (ß=0.23, p=0.007), independent of traditional cardiovascular risk factors and factors involved in bone formation. Increased PTH levels (>62 pg/mL) were associated with a 3.0-5.4-fold increased probability of having a mild-severe increase in aortic stiffness, irrespective of confounders. CONCLUSION: Among postmenopausal women with reduced 25-OH-vitamin D levels, elevated PTH levels were a significant predictor of aortic stiffness, irrespective of cardiovascular risk factors and of factors involved in bone formation. PTH accounted for the association between 25-OH-vitamin D levels and aortic stiffness.