| dc.contributor.author | Wong, Julia. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:35Z | |
| dc.date.available | 1997 | |
| dc.date.issued | 1997 | en_US |
| dc.identifier.other | AAINQ24766 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55506 | |
| dc.description | The main purpose of the present investigation was to examine the effects of age on blood pressure, arterial vasculature, and the heart. The pulse transit time and wave reflections were used as proxies for arterial stiffness, and the electrocardiographic estimate of the left ventricular mass index as the end point of age effects on the heart. Data were drawn from one of the five Yugoslavian male cohorts (Velika Krsna, n = 511), and one of the two Japanese male cohorts (Tanushimaru, n = 508) of the Seven Countries Study. The current study employed an epidemiological rather than clinical approach to investigate the age effects because the epidemiological approach could capture the widest possible spectrum of the aging phenomena and offer a powerful tool to discover associations among the biological and environmental variables related to cardiovascular aging. The clinical approach examines the relationship between age and variables of interest as they exist in a defined population at one particular time. | en_US |
| dc.description | Several linear regression models were introduced to assess the age effects on blood pressure, pulse transit time, pressure wave contour, and the left ventricular mass index. A small upward trend due to cohort-period effect, and a modest age increase were observed in blood pressure of the Yugoslavian cohort (systolic: 0.8 mmHg/year, diastolic: 0.2 mmHg/year, pulse pressure: 0.7 mmHg/year). The Japanese cohort showed a downward trend owing to cohort-period effect, but a steep upward age trend in blood pressure (systolic: 1.7 mmHg/year, diastolic: 0.6 mmHg/year, pulse pressure: 1.0 mmHg/year). Population stroke mortality is associated with blood pressure trends ascribable to cohort-period effect, and cohort stroke mortality is associated with blood pressure age trends, thus supporting the method of separating these two blood pressure trends. | en_US |
| dc.description | The pulse transit time was inversely correlated with age in the Yugoslavian (r = $-$0.38, p $<$ 0.001), but not Japanese cohorts. Blood pressures and heart rate were statistically significant determinants of pulse transit time in both cohorts. An analysis of the pooled sample indicated an inverse relationship between timing of wave reflections and age (r = $-$0.23, p $<$ 0.01). These findings suggest that increased arterial stiffness can be triggered by degenerative age changes in the arterial walls, or by augmented distending blood pressure. | en_US |
| dc.description | Age has a differential effect on the cardiac mass in these two cohorts; age and pulse pressure correlated significantly with the left ventricular mass index in the Japanese cohort, whereas body mass index and the systolic pressure load, but not age, were statistically significant determinants of the cardiac mass in the Yugoslavian cohort. These analyses suggest that increased cardiac mass is not a universal aging phenomenon. Other factors besides age participate in the development and/or maintenance of cardiac hypermoral. In conclusion, findings of the present investigation indicate that the vascular and cardiac responses to aging do not appear to be uniform in these two ethnically different populations. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1997. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Gerontology. | en_US |
| dc.subject | Sociology, Ethnic and Racial Studies. | en_US |
| dc.subject | Health Sciences, Human Development. | en_US |
| dc.subject | Biophysics, Medical. | en_US |
| dc.title | Effects of age on the arterial system and the heart. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
