How obesity and aging interact to create increased risk of osteoarthritis and disability
Abstract/Contents
- Abstract
- Obesity, a condition characterized by excess adipose tissue, is becoming an important public health problem. Not only has the prevalence rate in adults risen steadily since the 1980's, obesity is a strong risk factor for the development of knee osteoarthritis (OA) and general mobility disability. There are currently no disease-modifying treatments for OA, so it is important to develop preventive strategies. However, we must first understand the mechanism of increased risk in the obese population. Knee cartilage and other joint structures respond both to mechanical loads during activities of daily living and to the biological environment within the joint, so the pathway to OA in the obese population therefore likely involves changes in both. The primary goal of this dissertation was to test the hypothesis that aging and obesity are linked to changes in gait mechanics and changes in the relationship between cartilage morphology and joint loads, and that these changes are consistent with increased knee OA risk. We also analyzed whether these changes are also observed in individuals with early asymptomatic knee joint degeneration. Finally, we tested the hypothesis that stair climbing requires adaptive changes that reflect a reduction in muscle strength in the aging obese population and indicate increased mobility disability risk. The results indicate that in obese, but not normal-weight individuals, age was associated with an increased adduction moment, which reflects increased loads on the medial compartment of the knee. Furthermore, the positive relationship between cartilage thickness and ambulatory load in young subjects was significantly weaker in middle-aged obese individuals. The increased OA risk in older obese individuals is therefore likely due to both an increase in ambulatory loads and to a change in the relationship between those ambulatory loads and cartilage properties due to the elevated pro-inflammatory cytokine levels characteristic of obesity. During stair climbing, middle-aged obese individuals also had lower peak knee flexion moments, indicative of quadriceps weakness due to aging and relative to their weight. Finally, the gait and stair climbing mechanics of individuals with early OA were not different from their age- and BMI-matched healthy counterparts, indicating that the gait alterations seen in healthy middle-aged obese individuals are the same as those in obese individuals who have already developed the disease, and are likely risk factors or early functional markers of OA.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Blazek, Katerina |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Andriacchi, Th. P. (Thomas P.) |
| Thesis advisor | Andriacchi, Th. P. (Thomas P.) |
| Thesis advisor | Delp, Scott |
| Thesis advisor | Levenston, Marc Elliot |
| Advisor | Delp, Scott |
| Advisor | Levenston, Marc Elliot |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Katerina Blazek. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Katerina Blazek
- License
- This work is licensed under a Creative Commons Attribution Non Commercial Share Alike 3.0 Unported license (CC BY-NC-SA).
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