AbstractBackground: There are a number of factors that can negatively influence dietary intake and nutritional status amongst the older adult population, both nationally and globally. These can have clear consequences, not only for the individual, but also on a wider scale. It is well recognised that oral health can affect nutritional status and dietary intake, however the exact nature of this relationship and whether or not oral health would have a similar effect on dietary change, is unclear. A number of methods exist to improve nutritional status and modify energy intake. These include methods that can be targeted to specific population groups, such as prosthodontic rehabilitation, which can improve masticatory performance and overall oral health. There is also the need for methods which can be targeted to and implemented by the general population, such as modification of eating rate to slow down eating speed. However, whether these methods can influence a number of nutritional parameters including energy and nutrient intake, nutritional status and appetite measures, is not known.
Aims: This thesis set out to examine the factors affecting dietary intake, dietary change, nutritional status and appetite in older adults, and in particular how oral health status can influence nutritional status, dietary change and appetite measures. This main aim was broken down into five aims; to examine factors affecting diet in older people; to examine the effect of oral health on dietary change; to examine methods of improving and evaluating masticatory performance; to examine the relationship between masticatory performance and nutritional status; and to examine the effect of manipulating oral processing behaviours on appetite and energy intake.
Methods: This PhD involved:
1. Exploration of factors influencing dietary intake and adherence to dietary patterns amongst older adults in Northern Ireland participating in wave one of
the NICOLA study
2. Investigation, amongst adults at a high risk of cardiovascular disease in Northern Ireland, of how self-reported oral health status can influence dietary change and consumption of Mediterranean Diet-associated nutrients as part of a 12-month dietary intervention study (the TEAM-MED Extend study) to promote adherence to a Mediterranean Diet
3. Comparison of two tooth replacement strategies for partially dentate older patients, Conventional removable partial dental prosthesis treatment and functionally orientated shortened dental arch treatment, in terms of improving masticatory performance
4. Examination of correlations between objective, obtained using a two-colour chewing gum test, and subjective, using a self-report questionnaire, methods of evaluating masticatory performance
5. Investigation of how improvements in masticatory performance, as a result of removable partial dental prosthesis treatment or shortened dental arch methods of prosthodontic rehabilitation, can affect aspects of nutritional status as part of a randomised controlled trial in partially dentate older adults
6. Exploration of the relationship between masticatory performance, measured objectively and subjectively, and self-reported appetite measures
7. Investigation of whether there is a combined effect of manipulating oral processing behaviours, through consumption of foods differing in texture classified as “fast” or “slow” foods, and verbal instructions to chew slowly, on self-reported appetite measures and energy intake later in the day as part of a randomised crossover breakfast study
Results: A number of factors were found to be associated with lower fruit and vegetable intakes, lower adherence to healthy dietary patterns and higher adherence to unhealthy dietary patterns in a cross-sectional analysis of wave one data from the NICOLA study. These included being male, aged under 65, having a lower level of education, having a higher BMI, smoking, not being married, living alone, being widowed, having poor self-reported health or a long-term condition. However, the relationship between these factors and their influence on dietary intake and adherence to dietary patterns was not consistent (Chapter 2). Methods of improving and evaluating masticatory performance were compared; functionally oriented prosthodontic rehabilitation based on the shortened dental arch method was shown to
improve masticatory performance to an equivalent standard as the more commonly used conventional removable partial dental prosthesis treatment (Chapter 4), however no correlation was observed between objective (two-colour chewing gum) and subjective (self-report questionnaire) methods of evaluating masticatory performance (Chapter 5). Self-reported oral health status was shown to have an influence on daily intakes of Mediterranean Diet-associated nutrients in response to an intervention to promote adherence to a Mediterranean Diet, including fat and monounsaturated fatty acids, but not Mediterranean Diet Score (Chapter 3). Associations were observed between methods of evaluating masticatory performance, and certain appetite measures (Chapter 5). Improved masticatory performance, through prosthodontic rehabilitation, was not a predictor of improved nutritional status, however certain nutritional parameters did improve 12 months post-prosthodontic rehabilitation (Chapter 4). Combining methods to manipulate oral processing behaviours, such as bite size and number of chews per bite, was not found to have an effect on appetite measures or daily intakes of energy or nutrients, however associations were observed between these and specific oral processing behaviours (Chapter 5).
Conclusion: There are a number of factors that can influence dietary intake and adherence to dietary patterns amongst older adults in Northern Ireland. However, these factors may not have a consistent effect across both dietary intake and adherence to dietary patterns, and different measurements of the same age-related factor can result in varying degrees of influence on diet. Prosthodontic rehabilitation according to the shortened dental arch, which has been shown to improve oral health related quality of life and is acceptable to both clinicians and patients, was shown to improve masticatory performance to an equal standard as removable partial dental prostheses, and as these have a number of limitations, the adoption of shortened dental arch-based treatment in future clinical practice should be encouraged. As no correlations were observed between objective and subjective methods of evaluating masticatory performance, it would call into question the effectiveness of subjective methods in future work. Inconsistent relationships between oral health status and dietary change were observed, with self-reported oral health status influencing intakes of certain Mediterranean Diet-associated nutrients but not Mediterranean Diet Score. Prosthodontic rehabilitation was shown to improve masticatory performance; however, this was not a predictor of improved nutritional status, highlighting the potential need for a combined approach of dental treatment and dietary counselling. Although there was no observed combined effect of manipulating oral processing behaviours, through verbal instruction to chew slowly and modifying food texture, on energy intake and appetite measures, associations were observed between specific oral processing behaviours and certain appetite measures and nutrient intakes, therefore these should be the focus of future work in this area. The exact nature of the relationship between masticatory performance, oral health status, nutritional status and dietary change still remains unclear, and highlights the need for future intervention studies, carried out amongst older adults, incorporating multiple tools to assess oral health and diet.
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|Date of Award||Jul 2020|
|Sponsors||Northern Ireland Department for the Economy|
|Supervisor||Jayne Woodside (Supervisor) & Gerry McKenna (Supervisor)|
- oral health