- Title
- Diet and weight management in older adults with osteoarthritis
- Creator
- Webb, Emily Jessica
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Background: Osteoarthritis (OA) is a chronic and debilitating musculoskeletal condition, in which tissues in and around the joint are progressively damaged, resulting in poor physical and mental wellbeing. Research has shown a strong association between weight gain, overweight and obesity, and the risk of development or worsening of OA, particularly in the knee. As such, clinical OA management guidelines, within Australia and globally, routinely recommend weight loss of 5% of initial body weight, incorporating a hypocaloric diet and exercise, for those who are overweight or obese. Previous evidence synthesis has demonstrated that weight loss of this magnitude can significantly improve clinical outcomes such as pain, functional status, and quality of life. Further research has demonstrated greater weight loss of up to 20% can induce better improvements in these outcomes. However, extreme weight loss in the older population can have detrimental effects to body composition increasing the risk of frailty and disability. Research Aim: The overall aim of the thesis is to investigate the effect of nutrition and weight loss on physical function, body composition, symptoms and quality of life in overweight and obese older adults with OA. Thesis Study Methods: Study 1 was a systematic review and meta-analysis that investigated the effect of dietary weight loss interventions on physical function, in overweight and obese adults with OA. Study 2 was a second systematic review to further investigate the effect of weight loss on body composition, and the subsequent impact on muscle strength, physical function and biomarkers in knee OA. Study 3 was a cross-sectional study to assess nutrition, health and lifestyle behaviours of older adults with OA and investigate correlations with physical function. Finally, study 4 was a randomised-controlled trial (RCT) to investigate the effect of a Mediterranean style dietary intervention on physical and metabolic markers of health, in older overweight and obese adults with knee OA. This was followed up with an investigation of the feasibility of the study by telephone interviews with participants who completed the study. Findings: Findings of the first systematic review suggest that a conventional diet with partial use of meal replacements (i.e. up to two per day) is as effective as a more restrictive very-low energy diet (VLED) of ≤810 kcal/day using total meal replacements, for weight loss and improvements in physical function. While VLEDs are generally utilised for rapid and short-term weight loss, partial use of meal replacements may be more sustainable for long-term use. Both dietary interventions were more effective than a lifestyle intervention (conventional hypocaloric diet plus exercise) for improved physical function. Further, the second systematic review showed better retention of lean mass (LM) with a higher protein intake (i.e. ≥37% of energy) during dietary weight loss, which tended to show an association with maintenance of knee muscle strength and subsequently improved physical function. With protein intake of this magnitude being much higher than the national recommendations (15-25% of energy) it was imperative to assess dietary intakes of the older OA population. The majority of participants in the cross-sectional study were older than 65 years, over half of the sample had hypertension (54%) and were either overweight or obese (57%). Participants’ diets on average showed poor intakes of vegetables, breads and cereals, and milk and alternatives, compared to the dietary guidelines, and were high in saturated fat, low in carbohydrates, dietary fibre and key micronutrients, including folate, vitamin E and calcium, compared to national nutrient reference values. In comparison to the Australian population, participants had a considerably higher intake of total fat, particularly saturated fat, protein, and lower intake of total carbohydrates. As such, a Mediterranean style dietary intervention was developed with adaptations for older Australian adults to ensure nutritional adequacy. The Mediterranean style diet was chosen based on those “at risk” nutrients highlighted in the cross-sectional study, particularly saturated fat, carbohydrates and fibre, and observational studies showing potential benefit of dietary fat modification on joint health. With the exception of dietary intake, there were no significant differences between the treatment and control groups for most measures. Still, participants in the intervention group lost more weight and reported noticeable improvements in physical function, pain and emotional health. The feasibility study component highlighted participants’ satisfaction with the study, in particular the practicality and palatability of the intervention diet. Conclusion: This thesis presents an investigation of the effect of diet and weight management on physical function in older adults with OA. Synthesis of previous research in two systematic reviews demonstrated significant improvements in physical function with reductions in weight and fat mass, while the role of dietary protein for the retention of lean mass and muscle strength was also highlighted. Assessment of nutrition and lifestyle behaviours in the cross-sectional study demonstrated inadequate intake of key foods and nutrients, and as such this informed the development of a therapeutic Mediterranean style dietary intervention. Overall, findings of the thesis demonstrate the potential for a nutrient-rich eating pattern, with a focus on plant-based foods with modification of dietary fats for the management of OA. While weight management in overweight and obese adults with OA is a key treatment strategy, specific dietary strategies need to be further explored to ensure a safe magnitude of weight loss and maintenance of lean and bone mass in this population, to reduce the risk of frailty and disability.
- Subject
- osteoarthritis; physical function; diet; weight management
- Identifier
- http://hdl.handle.net/1959.13/1468184
- Identifier
- uon:48017
- Rights
- Copyright 2020 Emily Jessica Webb
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 5 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 402 KB | Adobe Acrobat PDF | View Details Download |