By posing fundamental questions about differences in rates and risks for pathological conditions associated with aging, studying groups with diverse racial, ethnic, and economic origins, we hope to understand the significance of environmental and genetic risk factors for disease. We have implemented a new study, Healthy Aging in Nationally Diverse Longitudinal Samples (HANDLS), to address these issues. We have also established a new paradigm for this type for research in making participation more likely by using a mobile medical research vehicle (MRV) to go where potential volunteers live. The vehicle, a 47-foot customized semi-trailer, has three working areas: an examination room with blood donor station; a cardiovascular fitness and muscle strength testing area; and a bone density and vascular studies testing area. The fundamental question posed by HANDLS is whether health disparities among minority and lower socioeconomic status subgroups are due to differences in socioeconomic status, differences in race, or their interaction. HANDLS focuses primarily on cerebrovascular health, cardiovascular health, and age-associated changes in cognition, psychophysiology, and strength and physical functioning. Using a longitudinal design with a representative sample from the Baltimore metropolitan area, we are examining whether there are differences in rates and risks for pathological conditions associated with aging that are associated with differences in socioeconomic status and race. The pilot phase of HANDLS, which began in October 2000, has the goal of the examining the feasibility of doing community-based clinical research in a mobile medical research vehicle. To this end, we have recruited a small sample of convenience from West Baltimore neighborhoods that range in age from 19-88. There are 358 active participants to date. The domains of the study are cardiovascular disease, cerebrovascular disease, age-associated changes in cognition, strength and physical functioning, and psychophysiology. The pilot phase of this study has been successful in addressing its primary goal assessing the feasibility of conducting a community-based study using a mobile medical research vehicle. The pilot has allowed us to refine the logistical requirements for the conduct of clinical research focused on several scientific and clinical domains among a diverse socioeconomic sample. The second goal of the pilot was to begin to collect data that would expand our understanding about the possible causes of health disparities in the African American community and the effect of race and socioeconomic status on health and the development of age-related disease and disability. Preliminary analyses of our psychophysiological data suggests important differences in blood pressure responses to certain stimuli among African American subjects that may be tied to differences in control of mechanisms of blood pressure. In addition our initial studies of affect suggest a higher rate of depressive symptomatology as measured by the CESD, a standard screen for depressive symptoms among community dwelling cohorts. This may suggest either a higher rate of depressive symptoms in the cohort we have studied and/or suggest that this widely used instrument is less accurate for screening in low SES and minority cohorts. We are presently pursuing this finding. Since accrual began we have obtained data on the beat-to-beat blood pressure and heart period during the completion of a psychological task. The task is designed to elicit information concerning the perception of emotion and consists of a baseline physiological recording period followed in counter-balanced order by the rating of pictures of facial emotions and the rating of emotion-descriptive sentences. These periods are followed by a recovery period identical to the baseline period. In addition, participants completed a number of questionnaires designed to measure aspects of psychosocial functioning including depression. Preliminary data analyses support the notion that there is a delay in cardiovascular recovery among African Americans that may be a potential factor in the cardiovascular health disparity between Blacks and Whites. In this sample of African Americans, blood pressures and heart rate increased from the baseline to the faces task and from the faces task to the sentences task. Importantly, during the recovery period blood pressure remained elevated. We were able to examine the physiological components of blood pressure, cardiac output and total peripheral resistance, and found evidence of elevated peripheral resistance during the recovery period. Previous research by NIA and IRP investigators has shown vascular hyper-reactivity among African Americans and the present results support these previous findings. However, in the present study we have also found evidence that this may be associated with important psychosocial factors. In the total sample, depression was positively correlated with cardiovascular reactivity to the tasks. In addition, in females we found a significant correlation between an item on the depression inventory measuring loneliness and the peripheral resistance response to the task. Specifically, increased loneliness was associated with increased vascular resistance. These results serve to highlight the multiple levels of system functioning that may contribute to the very significant health disparity in cardiovascular disease, especially hypertension. Further analyses will address the relationship between these findings and heart period and blood pressure variabilities. Analyses of the data in other domains of this study are currently underway and too preliminary to submit with this report. The current challenge to moving this study from its pilot (feasibility) phase to full operation is the design of the sampling frame that takes into account the need to develop a representative sample across SES strata among African Americans in Baltimore as well as to identify and include low SES whites of Baltimore in the cohort without making the study impractical to do from an operational standpoint.
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