Autonomic function and insulin resistance in a multiethnic population

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DESCRIPTION (provided by the applicant): Autonomic nervous system regulation of heartbeat variability is often disrupted among patients with diabetes. Moreover, reduced heart rate variability has been associated with increased Cardiovascular Disease (CVD) mortality among diabetic and non-diabetic populations. CVD mortality rates differ greatly among many ethnic groups. In Hawaii, Native Hawaiians have been shown to have disproportionately higher CVD mortality than Asian and Caucasian groups. Preliminary data from the Native Hawaiian Health Research Project suggest that conventional risk factors associated with Atherosclerosis may not fully account for ethnic disparities in heart disease and stroke mortality rates in Hawaii. Insulin resistance has been associated with increased CVD incidence and mortality, and has also been associated with reduced heart rate variability. The proposed study will investigate the relationship between insulin resistance and autonomic regulation of cardiac function in a multi-ethnic population. The proposed research will also provide baseline data for future longitudinal studies that will investigate the extent to which these novel risk factors explain ethnic disparities in CVD mortality in Hawaii. The findings of the proposed study may have important implications with regards to the treatment of insulin resistance as an independent CVD risk factor. Specific Aims: Collaborator component (Aim #1). Establish a collaborative laboratory in Hawaii for the evaluation of autonomic function in a multiethnic population. Principal Investigator component (Aim #2). Investigate the relationship between insulin resistance, body-fat distribution, and autonomic function. (Aim #3) Establish a cohort with baseline measures of autonomic function and insulin resistance that will serve as a study population for R01-supported longitudinal studies. Hypotheses: By fulfilling these specific aims, we propose to test the following specific research hypotheses: (1.) Autonomic function will differ significantly by ethnicity, after adjustment for age, gender, body-mass index, and central obesity. (2.) Insulin resistance is independently associated with autonomic function, after an adjustment for age, gender, body-mass index, and central obesity. Secondary Questions: Does insulin resistance and plasma glucose interact, in their effects on autonomic function? What role do plasma lipids, blood pressure, diet, and physical activity have in explaining any observed ethnic disparities in autonomic function? Is the questionnaire-derived Composite Autonomic Symptom Scale (COMPASS) correlated with autonomic function in Hawaii's multiethnic population?