The Analysis Of The Relationship Between Metabolic Syndrome And The Cerebrovascular Atherosclerosis Disease

Objective: The Metabolic syndrome (MS) consists of a combination of metabolic abnormalities, including abdominal obesity, high blood pressure, dyslipidemia and impaired glucose metabolism. In recent years, with population aging, excess food intake and sedentary lifestyle, the prevalence of the metabolic syndrome has gradually increased in all populations worldwide. According to the National Cholesterol Education Program Adult Treatment PanelⅢdefinition(NCEP ATPⅢ) ,the age-adjusted prevalence of MS among US adults in the National Health and Nutrition Examination Survey reports reached 23.1%[3].The existed studies indicate that MS is a risk factor for both diabetes mellitus(DM) and cardiovascular disease. The MS that accompanies DM is associated with an increased risk for morbility and mortality of coronary heart disease[1,2,5]. The research on the relationship between MS and cerebrovascular disease is rare. Recent studies suggested that MS was an important risk factor of stroke, but there were also the opposite results[7]. Stenosis or occlusion of cerebrovascular atherosclerosis in advanced stage is the main pathophysiological foundation for ischemic stroke and transient ischemic attack. Previous studies showed that cerebralvascular stenosis or occlusion account for 39%~70.98% of ischemic strokes[8,26]. Based on above all, we observed the prevalence of MS and its individual components in a cohort of hospitalized patients with high risk of cerebrovascular atherosclerosis to explore the relationship between MS and cerebrovascular atherosclerosis disease.Methods: We studied patients with acute ischemic stroke or with risk factors of cardiovascular disease, who were consecutively hospitalized from December 2006 to December 2007. All patients underwent Transcranical Doppler (TCD) and/or Magnetic Resonance Angiography (MRA) in the third hospital of hebei medical university to screen the cerebrovascular atherosclerosis stenosis or occlusion. Information obtained from all the subjects including demographic features, medical history and laboratory investigation was recorded.The diagnosis of acute ischemic stroke was based on history such as clinical course, associated signs and radiologic examination (Computerized Tomography, CT and/or Magnetic Resonance Imaging, MRI). According to TOAST classification [33], excluding the ischemic stroke of cardiac embolism and other undetermined etiology, only small artery occlusion(lacunar stroke)and large artery atherosclerosis stroke was remained.The risk factors of cardiovascular disease in our study such as hypertension, diabetes mellitus and hyperlipemia fulfilled their respective homologous criterions[16-18].We adopted the criteria of MS published by International Diabetes Federation (IDF),The study cohort was divided into two groups(MS group and non-MS group). We compared the mobidity of cerebrovascular atherosclerosis stenosis in MS group and non-MS group to evaluate the relationship of MS and its individual components and cerebrovascular atherosclerosis.According to fasting glucose and DM history, the MS subjects were classified into three subgroups: 1. MS with Normal Glucose Tolerance (NGT): fasting blood glucose level<5.6mmol/l and have no DM history; 2. MS with Impaired Fasting Glucose, IFG): fasting blood glucose level≥5.6mmol/l and<7.0mmol/l, have no DM history; 3. MS with Diabetes mellitus(DM): fasting blood glucose level≥7.0mmol/l or have DM history.We calculated the mobidity of cerebrovascular stenosis or occlusion among these subgroups,and Logistic regression models were used to determine the associations of differents level of fasting glucose and MS with stenosis.According to risk factors which constituted MS such as abdominal obesity, hypertension, high fasting glucose, high level of triglyceride, low level of high-density lipoprotein-cholesterol, The subjects were classified into five subgroups with different number of MS components.The relationship between different number of risk factors and stenosis were examined by logistic regression analysis.Result: 638 patients initially were enrolled, those were excluded if they had poor acoustic windows and lacked the results of MRA. Finally, 596 subjects were selected. Of the 596 subjects, the prevalence of MS was 62.75% (374/596). And the morbidity of cerebrovascular atherosclerosis stenosis was 47.86% in MS group, which is higher than those without MS(34.23%),the difference was statistically significant (χ2=10.5672,P=0.0012).Multiple logistic regression analysis for cerebrovascular atherosclerosis stenosis was performed using sex, age, smoking and MS as variables in these subjects, MS was significantly associated with cerebrovasculer stenosis, Odds ratio(OR) was 1.812.( 95%CI , 1.281~2.562 , P=0.0008). After adjusting ischemic stroke history, coronary heart disease, family history of stroke disease, hypercholesteremia, elevated serum low-density lipoprotein cholesterol level and MS parameters, MS was not an independent risk factor of cerebrovascular stenosis. (OR 0.780, 95%CI 0.407~1.493,P=0.4533). The risk factors significantly associated with cerebrovascular stenosis were as follows: ischemic stroke history (OR 2.342,95%CI,1.652~3.318,P<0.0001), hypercholesteremia(OR 1.970,95%CI,1.236~3.140,P=0.0044), hypertension or hypertension history(OR 1.960,95%CI,1.107~3.470,P=0.0209), hyperglycaemia or DM(OR 1.874 , 95%CI , 1.324~2.654 , P=0.0004),lowered serum high-density lipoprotein cholesterol level(OR 1.501,95%CI,1.061~2.123,P=0.0216). The presense of abdominal obesity(OR 0.862,95%CI,0.340~2.185,P=0.7541), hypertriglyceridemia (OR 0.573,95%CI,0.232~1.417,P=0.2281),and elevated serum low-density lipoprotein cholesterol level (OR 0.722, 95%CI 0.367~1.42,P=0.3458)didn't increase the risk of cerebrovascular stenosis after multivariate logistic regression analysis.Based on different fasting glucose levels and DM history, we divided the subjects with MS into MS with NGT, IFG and DM. The morbidity of cerebrovascular stenosis or occlusion respectively was 37.3%(47/126), 40.4%(19/47) and 56.2% (113/201).In logistic regression analysis, after adjusting for sex, age, smoking, ischemic stroke, coronary heart disease, family history of stroke disease, hypercholesteremia, elevated serum low-density lipoprotein cholesterol level and MS parameters, the association between MS with DM and cerebrovascular stenosis risk was strongly significant(OR 2.122,95%CI,1.471~3.061,P<0.0001).But MS with NGT and IFG were not independent risk factors for cerebrovascular stenosis. The OR of cerebrovascular stenosis associated with MS with NGT and IFG respective were 0.664(95%CI, 0.277~1.593, P=0.3596), 0.554(95%CI,0.283~1.082,P=0.0839).The morbidity of cerebrovascular stenosis among five subgroups which were classified with different number of MS components were in order as follows: 25.8%(16/62), 34.7%(50/144), 42.9%(79/184), 50.7%(75/148), 60.34%(35/59). The results suggested that patients with more number of MS components were more likely to have cerebrovascular atherosclerosis stenosis. In multivaviate logistic regression analysis, Only subjects with four or five MS components significantly increased the risk of cerebrovascular stenosis, after adjusting for age, sex, smoking, ischemic stroke , coronary heart disease, family history of stroke disease. The odds ratio for those with four or five MS components respectively was 1.577(95%CI , 1.075~2.311 , P=0.0197) , 2.210(95%CI, 1.255~3.892, P=0.006).The subjects with zero or one MS component (OR0.442, 95%CI 0.242~0.809,P=0.0081),with two MS components (OR0.625, 95%CI 0.420~0.932,P=0.0210),with three MS components (OR0.989, 95%CI 0.689~1.420, P=0.9526),didn't increase the risk of the cerebrovascular stenosis.Conclusion: MS was significantly associated with cerebrovascular atherosclerosis stenosis, but the association of MS and cerebrovascular atherosclerosis stenosis reply on individual components of MS. MS is not an independent risk factor for cerebrovascular stenosis. The risk factors significantly associated with cerebrovascular stenosis were as follows: ischemic stroke history, hypercholesteremia, hypertension or hypertension history, hyperglycaemia or DM, lowered serum high-density lipoprotein cholesterol level. Furthermore, the subjects with both MS and DM increased the risk of cerebrovascular stenosis more than those MS or MS but without DM, which did not depend on the individual components of MS. The subjects with four or five MS components significantly increased the risk of cerebrovascular stenosis.