Doctor of Philosophy (PhD)
Aging and age related disease affects individuals differently. One possible explanation could be free radical production varies among individuals and this variation determines the aging process and the progression of disease. The purpose of this study was to test whether nonagenarians have a relatively low metabolic rate when compared to younger individuals and whether this low metabolic rate is associated with lower levels of oxidative stress and less incidence of disease. Resting metabolic rate (RMR), markers of oxidative stress to lipids, proteins, and DNA, components of the metabolic syndrome, and physical activity level were measured in 3 groups of individuals aged 20-34 (16M/25F), 60-74 (16M/11F), and >90y (23M/25F). RMR, adjusted for fat-free mass, fat mass, and sex was significantly lower in both of the older groups when compared to the younger group (p<0.007). Nonagenarians had significantly (p<0.01) lower DNA damage than the middle-aged subjects (60-74y). However, there were also no significant relationship between RMR and any of the markers of oxidative stress. Nonagenarians had less prevalence of the metabolic syndrome than the aged individuals; however, this was not related to reduced levels of oxidative stress. The current study confirms previous findings of an age related decline in RMR adjusted for body weight and body composition. In addition, nonagenarians appeared to be protected from an age-related increase in DNA damage and development of the metabolic syndrome. However, there was no relationship between the level of oxidative damage and RMR challenging the rate of living/ oxidative stress hypothesis.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Frisard, Madlyn Irene, "Health and lifestyle profiles across the lifespan: results from the Louisiana Healthy Aging Study" (2005). LSU Doctoral Dissertations. 1162.