Frailty, nutrition & healthy ageing : evaluating nutrition risk in support of healthy ageing : the enrich study towards enriching life in older age : thesis submitted in partial fulfilment of the requirements of Doctor of Philosophy in Nutritional Sciences, Massey University, New Zealand

Abstract

Background: New Zealand is one of the countries experiencing a significant change in the population pyramid, characterised by an increase in the number of older adults (≥65 years old) compared to younger age groups. Worldwide, increases in the number of older adults is associated with increases in national health costs, and currently nearly half (42%) of the New Zealand’s district health board expenses are being used for support services of older adults. This begs the question whether healthy ageing is being attained; and which strategies can be employed to prevent health loss with advancing age. The evidenced based literature presents an undebatable association between malnutrition (undernutrition) and adverse health outcomes among older adults, which calls for research to identify ways to prevent malnutrition. Aim and objectives: The overarching aim of this research was to obtain evidence-based data that will help inform policy and practice on the importance of routine screening for malnutrition (risk); and to inform intervention planning towards preventing malnutrition and associated adverse health outcomes among older adults. After identifying research gaps in New Zealand, specific objectives of this thesis were 1) To investigate the associations between malnutrition risk status, body composition and physical performance among community-dwelling older New Zealanders – [study 1]; 2) To investigate the magnitude and potential predictors of malnutrition risk in older adults, at hospital admission – [study 2]. 3) To report the overlapping prevalence of malnutrition and frailty at admission to Residential Aged Care (RAC), and to evaluate the prevalence and factors associated with malnutrition and frailty – [study 3]. 4) To explore older adults’ perspectives and experiences of food and nutrition intake, to gain new insights to factors that influence vulnerability to malnutrition risk– [study 4]. The findings of the four studies were then synthesised to inform recommended intervention strategies to prevent malnutrition with advancing age [discussion]. Methods: This research used a mixed methodology design including three cross-sectional quantitative studies and one qualitative. The three quantitative studies involved assessment of malnutrition status using the Mini Nutritional Assessment Short Form (MNA®SF) and several potential risk factors (Assessment procedure) for malnutrition including body composition (Bio-impedance analysis scale), upper body muscle strength (Hand grip strength), lower body muscle strength and mobility (Five times sit to stand test and Gait speed), Frailty status (Fried phenotype model), dental status (Dentate, non-dentate or use of dental appliances), dysphagia risk (Eating Assessment Tool EAT-10) and cognitive status (Montreal cognitive assessment tool). In the comprehensive qualitative study, an in-depth interview lasting about an hour per participant was conducted. The in-depth interviews were recorded and transcribed verbatim. Thematic content analysis of the transcripts was conducted using the integrated approach. Results: We found the prevalence of malnutrition and malnutrition risk respectively of 1% and 11% in the community, 26.9% and 46.6% at admission to the hospital, and 48% and 45% at admission to RAC. Nearly half (43%) of the participants were both frail and malnourished at admission to RAC. From the quantitative work [studies 1-3], the key predictors or risk factors identified for malnutrition were related to physiological frailty –Fried phenotype model, low muscle strength, muscle mass, gait speed, dysphagia risk, and psychological frailty – low cognition. From the qualitative work [study 4], thematic analysis of the participants’ perspectives and experiences of food intake identified six main themes which contribute to understanding the increasing vulnerability to malnutrition with advancing age. A synthesis of the six themes indicated that the key factors that potentially increase risk of malnutrition encompasses all the three dimensions of frailty i.e. physiological – low appetite, comorbidities imposing food restrictions and physical challenges restraining food procurement, preparation or eating; psychological & social frailty – loneliness, living alone, carer stress and symptoms of depression, which altogether promote low food intake. Conclusion: The central thesis of this research indicates malnutrition risk is highly prevalent across New Zealand settings, and may be prevented or treated through timely screening and person-centred interventions. Although a lower prevalence of malnutrition is recorded in the community, the quantitative data collected across settings provide evidence that the risk of malnutrition starts in the community, and early intervention is paramount in institutions as several older people enter hospital and RAC when already malnourished or at risk. Analysis of the qualitative data collected from older adults provided unique perspectives on factors that shape older New Zealanders eating habits. These support international recommendations for researchers to pay attention to older adults’ perspectives towards designing appropriate interventions. Overall, the thesis findings indicate that policy and practice interventions should be aimed at preventing or reducing the prevalence of all three dimensions of frailty, in order to attain both optimal nutrition intake and healthy ageing. Mandatory screening for malnutrition (targeted in the community and routinely in institutions) is the first step to ensure timely intervention.