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About 1,100,000 Americans have first or second heart attack each year, and one third of the heart attack is fatal. Stroke affects 500,000 Americans, and it kills 150,000 men and women each year. Heart attack and stroke combined are the leading cause of death and disability in the United States.
Atherosclerosis, which involves arterial (large blood vessel) wall thickening and hardening, often with thrombosis, which involves obstruction of the blood supply, has been shown to be the common disease process leading to heart attack and stroke.
Scientific studies suggest that cigarette smoking is an important cause of heart attack and stroke. Although the causal link between smoking and these atherosclerotic diseases has been well established over the past 30 years, less is known on how cigarette smoking impacts the development of atherosclerosis.
Metabolic syndrome, which is a group of metabolic variables including high blood insulin level, high glucose level, obesity, abdominal obesity, low good cholesterol, and high blood fat, is also found to increase the risk of atherosclerosis.
Smokers demonstrate many features that are similar to the metabolic syndrome. These similarities indicated that smoking might be related to increased risk of the metabolic syndrome. This theory is supported by some scientific studies. However, conflicting evidence also exists. The relationship between metabolic syndrome and cigarette smoking is worthy of further investigation, especially in middle-aged adults who are more likely to develop metabolic syndrome and atherosclerosis.
The following specific objectives are proposed: (1) assess the utility of arterial wall thickness and arterial wall stiffness measured by ultrasound as the indices of atherosclerosis; (2) examine sex differences in relating smoking and the metabolic syndrome to atherosclerosis in middle-aged adults; (4) determine whether smoking worsens the effects of the metabolic syndrome on atherosclerosis; (5) investigate whether part of the adverse effects of smoking on atherosclerosis is mediated by metabolic syndrome. The data was obtained from an ongoing study, Los Angeles Atherosclerosis Study (LAAS), which include assessment of health-related behaviors, physiological and metabolic measures, and surrogate measures of atherosclerosis among middle-aged adults (304 men and 269 women). Three exams with 18- month intervals will be included in the analyses.
This study will improve our understanding of the causes of the tobacco-related disease that has the largest impact on the health of Californians. Moreover, the application of structural equation model and Mixed model allow examination of effects of several risk factors and outcomes simultaneously, and using the data from three exams in an efficient way. Finally, since ultrasonic detection of early atherosclerosis used in this study is convenient and relatively low-cost, positive findings would enable physicians assess the risk of heart attack and stroke far prior to the occurrence of fatal events. This early detection facilitates primary prevention and smoking cessation efforts. |
