Catherine M. Stoney - US grants

This project assesses the effects of chronic behavioral stress on lipids, lipoproteins, and apolipoproteins in a healthy male, normolipidemic population. It tests several pathways of model proposing that chronic behavioral stress has this effect (a) because of alterations in health behaviors, such as physical activity, body weight, diet and nutritional factors; (b) because of direct effects of stress on lipids; and (c) most notably in a particularly sensitive subset of individuals. To test this model, this project will utilize a chronic occupational stressor, acute laboratory challenges, behavioral assessment, and a dietary challenge. In addition, it will employ state-of-the-art methods of measuring behavioral changes, such as diet, body weight, and physical activity patterns. The project will utilize a sample of health middle-aged males who are known to predictably experience both high and low degrees chronic occupational stress. Subjects will each participate in three health behavior assessments, scheduled during a period of low chronic occupational stress, followed by one of high chronic occupational stress, and concluding With a period of low chronic occupation stress. During these sessions, information regarding physical activity, dietary intake, body weight and several other health behaviors will be collected. The final session will conclude with a laboratory session designed to psychologically and physically challenge the participants, while lipids, lipoproteins, and apolipoproteins are being assessed. Statistical analyses are hypothesis-driven and designed to specifically test several pathways of the proposed model.

DESCRIPTION (provided by applicant): Homocysteine is putative risk factor for coronary heart disease (CHD). It is an amino acid associated with endothelial damage, which may cause direct injury to intimal cells and assist in the deposition of lipoproteins within atherosclerotic lesions. Homocysteine is bound to lipoproteins. Although several psychological characteristics are associated with CHD, few investigations of psychological risk factors and homocysteine exist. We have shown that homocysteine increases during stress, and that hostility is positively associated with resting homocysteine. The major goals of this proposal are to investigate the etiological significance of stress-induced and personality-associated elevations in homocysteine; to evaluate the relationship between lipids and homocysteine during stress; and to test one viable mechanism for homocysteine reactivity. Study 1 will test whether the stress-associated increases in homocysteine are etiologically meaningful, by comparing individuals with above average risk for CHD (based on American Heart Association/American College of Cardiology recommendations and family history), to those at below average risk. This study will also build on our earlier findings, by comparing homocysteine reactivity among high hostile individuals to low hostile individuals. Study 2 will test whether individuals with exaggerated homocysteine reactivity have greater stress-induced alterations in vitamin B6, vitamin B12, and folate than do those with smaller homocysteine reactivity. An additional purpose of this study will be to test whether individuals given B vitamin supplements for 4 weeks prior to an acute stressor display smaller elevations in stress-induced homocysteine, relative to individuals given placebo. Because homocysteine is bound to lipoproteins, and because it appears to modify the atherogenicity of low density lipoprotein, both studies will test the relationships between homocysteine and lipid reactivity. The results of this research will extend the available but limited data testing the impact of stress and hostility on homocysteine concentrations; will allow one test of the etiological significance of stress-related homocysteine elevations; will allow us to examine the relationship between lipid reactivity and homocysteine reactivity; and will test a viable mechanism for the homocysteine elevations.

hypothalamic pituitary adrenal axis; psychological stressor; coping; cardiovascular function; interpersonal relations; emotional dependency; physiology; adult human (21+); psychoanalysis; psychological adaptation; behavioral /social science research tag; human subject; clinical research;