The ageing population is predicted to exceed two billion by 2050; maintaining good health in older age has, thus, become a major global health priority. Ageing involves physiological changes, impairment in digestive function and the increased need for the use of prescribed drugs which can lead to lower status of folate and the metabolically related B-vitamins (vitamins B I2, B6, riboflavin). Deficiencies in these vitamins are increasingly linked with a number of chronic diseases of ageing. In particular, dementia affects 46.8 million globally, figures that are expected to triple by 2050, generating substantial societal and economic impacts. One-carbon metabolism is proposed as a critical pathway associated with health throughout life, especially in ageing. However, studies considering the association of one-carbon metabolism tend to focus on folate and vitamin B 12, few have considered all the relevant B-vitamins which are interlinked within one-carbon metabolism. The overall aim of this thesis therefore, was to investigate the causes, consequences and public health implications of low B-vitamin status in ageing with a particular focus on cognitive health. Results arising from new analysis of the Trinity, Ulster and Department of Agriculture (TUDA) Ageing cohort study (n 5186) indicated that the use of proton pump inhibitors (PPI), widely taken by older people, is associated with significantly lower status of B12 as previously reported, but also with lower status of vitamin B6 and riboflavin, vitamins which have not previously been linked with PPI use. Likewise, metformin use was associated with a significant increase in the risk of vitamin B12 deficiency and more than doubled the risk of vitamin B6 deficiency, in older people with or at-risk of diabetes (HbAic<42mmol/mol). The thesis showed that older adults with or at-risk of diabetes were at a 25% higher risk of vitamin B6 deficiency, and a 67% increased risk of cognitive dysfunction, with some evidence that low status of vitamin B6 may be driving the cognitive dysfunction in these patients. In a follow up study of almost 600 participants, 5 years after the initial investigation (i.e. TUDA+5), low status of vitamin B6 (OR: 1.75, P 0.008) and riboflavin (OR 1.63, P 0.018) were found to be significant predictors of accelerated cognitive decline, as measured by RBANS. The totality of the evidence in this thesis supports the wider public health benefits of optimising B-vitamin status, through natural food sources, fortified foods and supplements, to alleviate B-vitamin depletion in those on long term prescribed drugs and as a means of maintaining cognitive health in ageing. In conclusion, results from this thesis suggest that updating food fortification policies worldwide to optimise all the relevant B-vitamins could offer a cost-effective strategy for maintaining better health in ageing and preventing adverse outcomes.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:763930 |
| Date | January 2017 |
| Creators | Porter, Kirsty Michelle |
| Publisher | Ulster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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